SARS-CoV-2 RNA positive pediatric organ donors: A case report

BACKGROUND

Preliminary evidence suggests that non-lung organ donation from resolved, asymptomatic or mildly symptomatic SARS-CoV-2 infected adults may be safe. However, several biological aspects of SARS-CoV-2 infection differ in children and the risk for transmission and outcomes of recipients from pediatric donors with SARS-CoV-2 infection are not well described.

METHODS

We report two unvaccinated asymptomatic pediatric non-lung organ deceased donors who tested positive for SARS-CoV-2 RNA by RT-PCR. Donor One unexpectedly had SARS-CoV-2 RNA detected in nasopharyngeal swab and plasma specimens at autopsy despite several negative tests (upper and lower respiratory tract) in the days prior to organ recovery. Donor Two had SARS-CoV- 2 RNA detected in multiple nasopharyngeal swabs but not lower respiratory tract specimens (endotracheal aspirate and bronchoalveolar lavage) during routine surveillance prior to organ recovery and was managed with remdesivir and monoclonal antibodies prior to organ recovery.

RESULTS

Two hearts, two livers and four kidneys were successfully transplanted into seven recipients. No donor to recipient transmission of SARS-CoV-2 was observed and graft function of all organs has remained excellent for up to 7 months of followup.

CONCLUSIONS

Due to the persistent gap between organ availability and the number of children waiting for transplants, deceased pediatric patients with non-disseminated SARS-CoV-2 infection, isolated to upper and/or lower respiratory tract, should be considered as potential non-lung organ donors.

Interaction of Critical Care Practitioners With a Decision Support Tool for Weaning Mechanical Ventilation in Children

BACKGROUND

There is evidence that ventilator weaning protocols provide benefit to children receiving mechanical ventilation, but many protocols do not include explicit instructions for decreasing ventilator support from maximal settings. We evaluated care provider opinions on ventilator weaning recommendations made by a computerized decision support tool.

METHODS

Recommendations for ventilator adjustment were generated using a computerized decision support tool based on the ARDSNet protocol using data from children with acute hypoxemic respiratory failure admitted to the pediatric ICU (PICU). Attending physicians, fellows, nurse practitioners, and respiratory therapists (RTs) caring for these patients answered a brief survey to assess whether recommendations were reasonable and whether the practitioner believed they could be implemented.

RESULTS

RTs completed 99 surveys and ICU providers completed 96 surveys based on data from 10 patients. RTs and ICU providers found 63.9% and 65.3% of recommendations reasonable, respectively. There were 5 instances of disagreement between RTs and ICU providers. The percent of recommendations that RTs thought could be implemented was 29.9%, whereas this figure for ICU providers was 26.3%, with 4 instances of disagreement. Free-text responses indicated that many RTs and ICU providers were concerned about disrupting current patient stability and low tidal volumes.

CONCLUSIONS

On initial evaluation, the decision support tool did not appear to be highly acceptable to RTs and ICU providers in our setting because recommendations were rarely implemented. In addition, acceptability did not increase over time as patients generally improved. Most respondents preferred to make no ventilator changes and felt the recommendations were too aggressive. The notable barrier to use was a perception of potential patient instability with weaning.

An Elevated Low Cardiac Output Syndrome Score Is Associated With Morbidity in Infants After Congenital Heart Surgery

OBJECTIVES

To evaluate an empirically derived Low Cardiac Output Syndrome Score as a clinical assessment tool for the presence and severity of Low Cardiac Output Syndrome and to examine its association with clinical outcomes in infants who underwent surgical repair or palliation of congenital heart defects.

DESIGN

Prospective observational cohort study.

SETTING

Cardiac ICU at Seattle Children's Hospital.

PATIENTS

Infants undergoing surgical repair or palliation of congenital heart defects.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Clinical and laboratory data were recorded hourly for the first 24 hours after surgery. A Low Cardiac Output Syndrome Score was calculated by assigning one point for each of the following: tachycardia, oliguria, toe temperature less than 30°C, need for volume administration in excess of 30 mL/kg/d, decreased near infrared spectrometry measurements, hyperlactatemia, and need for vasoactive/inotropes in excess of milrinone at 0.5 μg/kg/min. A cumulative Low Cardiac Output Syndrome Score was determined by summation of Low Cardiac Output Syndrome Score on arrival to cardiac ICU, and 8, 12, and 24 hours postoperatively. Scores were analyzed for association with composite morbidity (prolonged mechanical ventilation, new infection, cardiopulmonary arrest, neurologic event, renal dysfunction, necrotizing enterocolitis, and extracorporeal life support) and resource utilization. Fifty-four patients were included. Overall composite morbidity was 33.3%. Median peak Low Cardiac Output Syndrome Score and cumulative Low Cardiac Output Syndrome Score were higher in patients with composite morbidity (3 [2-5] vs 2 [1-3]; p = 0.003 and 8 [5-10] vs 2.5 [1-5]; p < 0.001)]. Area under the receiver operating characteristic curve for cumulative Low Cardiac Output Syndrome Score versus composite morbidity was 0.83, optimal cutoff of greater than 6. Patients with cumulative Low Cardiac Output Syndrome Score greater than or equal to 7 had higher morbidity, longer duration of mechanical ventilation, cardiac ICU, and hospital length of stay (all p ≤ 0.001). After adjusting for other relevant variables, peak Low Cardiac Output Syndrome Score and cumulative Low Cardiac Output Syndrome Score were independently associated with composite morbidity (odds ratio, 2.57; 95% CI, 1.12-5.9 and odds ratio, 1.35; 95% CI, 1.09-1.67, respectively).

CONCLUSION

Higher peak Low Cardiac Output Syndrome Score and cumulative Low Cardiac Output Syndrome Score were associated with increased morbidity and resource utilization among infants following surgery for congenital heart defects and might be a useful tools in future cardiac intensive care research. Independent validation is required.

Effects of exendin-4, a glucagon like peptide-1 receptor agonist, on neutrophil count and inflammatory cytokines in a rat model of endotoxemia

Background

Sepsis remains a major cause of morbidity and mortality. A variety of strategies targeting modulation of the pro-inflammatory response associated with early sepsis have been reported without clinical success. GLP-1 enhances glucose-stimulated insulin secretion. In addition, it was shown to have anti-inflammatory effects. We hypothesized that treatment with exendin-4, a GLP-1 receptor agonist, would attenuate inflammation and improve glucose control in a lipopolysaccharide (LPS) rat model of inflammation.

Methods

Two-month-old male Wistar rats were randomly assigned to one of the following four groups: 1) treatment: intraperitoneal (IP) injection of LPS 10 mg/kg followed by exendin-4, 30 μg/kg, 10 minutes later; 2) control-1: IP injection of LPS 10 mg/kg, followed by normal saline (NS); 3) control-2: IP NS injection followed by exendin-4; 4) sham: IP injection of NS followed by another NS injection. Glucose concentration, total white blood count with absolute neutrophil count, and pro- and anti-inflammatory cytokine concentrations were measured at 0, 3, 6, and 10 hours following LPS injection.

Results

At 3 hours, rats injected with LPS developed neutropenia, elevated pro- and anti-inflammatory cytokines, and mild hypoglycemia. Treatment with exendin-4 significantly modulated neutropenia, and decreased pro-inflammatory cytokine concentrations (IL-1α, IL-1β, IL-6, TNFα, and IFNγ). However, exendin-4 had no effect on IL-10 concentrations. LPS injection led to mild hypoglycemia, that was not observed in rats treated with exendin-4. Sham animals exhibited no significant change from baseline in all parameters.

Conclusion

In this LPS model of acute early phase inflammation, treatment with exendin-4 decreased pro-inflammatory cytokine concentrations without changing IL-10 blood levels and improved neutropenia. Following LPS injection, rats developed a tendency toward hypoglycemia that improved with exendin-4. Overall our data suggest that exogenous exendin-4 mediates anti-inflammatory effects early in this rat model of endotoxin-induced inflammation.

Two pediatric cases of variant neurogenic stress cardiomyopathy after intracranial hemorrhage

Takotsubo cardiomyopathy, also known as stress-induced cardiomyopathy, is an acquired form of left ventricular systolic dysfunction seen in the setting of physiologic stress and the absence of coronary artery disease. It is thought to be caused by excessive sympathetic stimulation. It is well described in the adult literature associated with subarachnoid hemorrhage where it is known as neurogenic stress cardiomyopathy (NSC), but few such pediatric cases have been reported. We describe our experience with 2 children (13- and 10-year-old girls) who presented with spontaneous intracranial hemorrhage followed by pulmonary edema and shock. Echocardiography revealed similar patterns of left ventricular wall motion abnormalities consistent with NSC, inverted Takotsubo variant. One child progressed to death, whereas the other made a remarkable recovery, including significant improvement in cardiac function over the course of 1 week. We argue that at least 1 of these cases represents true stress-induced cardiomyopathy. This report will alert pediatricians to this transient cardiomyopathy that is likely underdiagnosed in pediatric intensive care. We also highlight the challenges of managing both shock and elevated intracranial pressure in the setting of NSC.

Common endocrine issues in the pediatric intensive care unit

Thyroid hormone is central to normal development and metabolism. Abnormalities in thyroid function in North America often arise from autoimmune diseases, but they rarely present as critical illness. Severe deficiency or excess of thyroid hormone both represent life-threatening disease, which must be treated expeditiously and thoroughly. Such deficiencies must be considered, because presentation may be nonspecific.

Repeated lentivirus-mediated granulocyte colony-stimulating factor administration to treat canine cyclic neutropenia

Cyclic neutropenia occurs in humans and gray collie dogs, is characterized by recurrent neutropenia, and is treated by repeated injections of recombinant granulocyte colony-stimulating factor (rG-CSF). As dose escalation of lentivirus may be clinically necessary, we monitored the outcome of four sequential intramuscular injections of G-CSF-lentivirus (3 × 10(7) IU/kg body weight) to a normal dog and a gray collie. In the normal dog absolute neutrophil counts were significantly increased after each dose of virus, with mean levels of 27.75 ± 3.00, 31.50 ± 1.40, 35.05 ± 1.68, and 43.88 ± 2.94 × 10(3) cells/μl, respectively (p<0.001), and elevated neutrophil counts of 31.18 ± 7.81 × 10(3) cells/μl were maintained for more than 6 years with no adverse effects. A gray collie dog with a mean count of 1.94 ± 1.48 × 10(3) cells/μl received G-CSF-lentivirus and we observed sustained elevations in neutrophil levels for more than 5 months with a mean of 26.00 ± 11.00 × 10(3) cells/μl, significantly increased over the pretreatment level (p<0.001). After the second and third virus administrations mean neutrophil counts of 15.80 ± 6.14 and 11.52 ± 4.90 × 10(3) cells/μl were significantly reduced compared with cell counts after the first virus administration (p<0.001). However, after the fourth virus administration mean neutrophil counts of 15.21 ± 4.50 × 10(3) cells/μl were significantly increased compared with the previous administration (p<0.05). Throughout the nearly 3 years of virus administrations the dog gained weight, was healthy, and showed neutrophil counts significantly higher than pretreatment levels (p<0.001). These studies suggest that patients with cyclic and other neutropenias may be treated with escalating doses of G-CSF-lentivirus to obtain a desired therapeutic neutrophil count.

Sustained glucagon-like peptide 1 expression from encapsulated transduced cells to treat obese diabetic rats

Obesity and type 2 diabetes (T2D) are two prevalent chronic diseases that have become a major public health concern in industrialized countries. T2D is characterized by hyperglycemia and islet beta cell dysfunction. Glucagon-like peptide 1 (GLP-1) promotes β cell proliferation and neogenesis and has a potent insulinotropic effect. Leptin receptor deficient male rats are obese and diabetic and provide a model of T2D. We hypothesized that their treatment by sustained expression of GLP-1 using encapsulated cells may prevent or delay diabetes onset. Vascular smooth muscle cells (VSMC) retrovirally transduced to secrete GLP-1 were seeded into TheraCyte(TM) encapsulation devices, implanted subcutaneously and rats were monitored for diabetes. Rats that received cell implants showed mean plasma GLP-1 level of 119.3 ± 10.2pM that was significantly elevated over control values of 32.4 ± 2.9pM (P<0.001). GLP-1 treated rats had mean insulin levels of 45.9 ± 2.3ng/ml that were significantly increased over control levels of 7.3±1.5ng/ml (P<0.001). In rats treated before diabetes onset elevations in blood glucose were delayed and rats treated after onset became normoglycemic and showed improved glucose tolerance tests. Untreated diabetic rats possess abnormal islet structures characterized by enlarged islets with α-cell infiltration and multifocal vacuolization. GLP-1 treatment induced normalization of islet structures including a mantle of α-cells and increased islet mass. These data suggest that encapsulated transduced cells may offer a potential long term treatment of patients.

Prolonged survival and improved glycemia in BioBreeding diabetic rats after early sustained exposure to glucagon-like peptide 1

BACKGROUND

Type 1 diabetes (T1D) in both humans and BioBreeding (BB) rats is an autoimmune disease that results in complete destruction of islets and insulin dependency for life. Glucagon-like peptide 1 (GLP-1) promotes beta cell proliferation and neogenesis and has a potent insulinotropic effect. We hypothesized that the expression of GLP-1 before disease onset would increase islet mass, delay diabetes and prolong survival of BB rats.

METHODS

Vascular smooth muscle cells retrovirally transduced to secrete GLP-1 were seeded into TheraCyte encapsulation devices, implanted subcutaneously, and rats were monitored for diabetes.

RESULTS

In untreated control rats, plasma GLP-1 levels were 34.5-39.5 pmol/l, whereas, in treated rats, plasma levels were elevated, in the range 90-250.4 pmol/l. Hypoglycemia was not detected and this was anticipated from the glucose-regulated action of GLP-1. Diabetes onset (mean + or - SEM) in untreated rats occurred at 56.5 + or - 0.6 days (n = 6) and, in GLP-1-treated rats, was delayed until 76.4 + or - 3.3 days (n = 5) (p < 0.001). After disease onset, untreated control rats showed a rapid weight loss and elevated blood glucose (>650 mg/dl) and did not survive beyond 11 days. At 5 days after diabetes onset, insulin-secreting islets were absent in untreated rats. By contrast, treated rats maintained weight for up to 143 days of age and showed insulin-secreting beta cells.

CONCLUSIONS

Sustained GLP-1 expression delivered by encapsulated cells before diabetes onset in BB rats showed an improved clinical outcome, suggesting the potential for treating patients using long lasting GLP-1 analogs.

Treatment of diabetic rats with encapsulated islets

Immunoprotection of islets using bioisolator systems permits introduction of allogeneic cells to diabetic patients without the need for immunosuppression. Using TheraCyte™ immunoisolation devices, we investigated two rat models of type 1 diabetes mellitus (T1DM), BB rats and rats made diabetic by streptozotocin (STZ) treatment. We chose to implant islets after the onset of diabetes to mimic the probable treatment of children with T1DM as they are usually diagnosed after disease onset. We encapsulated 1000 rat islets and implanted them subcutaneously (SQ) into diabetic biobreeding (BB) rats and STZ-induced diabetic rats, defined as two or more consecutive days of blood glucose >350 mg/dl. Rats were monitored for weight and blood glucose. Untreated BB rats rapidly lost weight and were euthanized at >20% weight loss that occurred between 4 and 10 days from implantation. For period of 30–40 days following islet implantation weights of treated rats remained steady or increased. Rapid weight loss occurred after surgical removal of devices that contained insulin positive islets. STZ-treated rats that received encapsulated islets showed steady weight gain for up to 130 days, whereas untreated control rats showed steady weight loss that achieved >20% at around 55 days. Although islet implants did not normalize blood glucose, treated rats were apparently healthy and groomed normally. Autologous or allogeneic islets were equally effective in providing treatment. TheraCyte™ devices can sustain islets, protect allogeneic cells from immune attack and provide treatment for diabetic-mediated weight loss in both BB rats and STZ-induced diabetic rats.

G-CSF-lentivirus administration in rats provided sustained elevated neutrophil counts and subsequent EPO-lentivirus administration increased hematocrits

BACKGROUND

Towards gene therapy treatment of patients with neutropenia, characterized by neutrophil counts < 500 cells/microl, we investigated the ability of lentivirus vectors to provide sustained granulocyte colony-stimulating factor (G-CSF) delivery and to permit transgene expression from a second virus administration in a preclinical rat model.

METHODS

Rats were injected intramuscularly (IM) with 24 x 10(6) and 9 x 10(6) infectious units (IU) of a VSV-G-pseudotyped self-inactivating (SIN) lentivirus encoding rat G-CSF cDNA and containing cPPT and PRE elements. To determine the effectiveness of a second virus administration treated rats and a naïve rat received erythropoietin (EPO)-lentivirus IM. Rats were monitored for neutrophil and red blood cell production. Lentivirus antibodies were assayed by virus-neutralizing assay and ELISA.

RESULTS

High and low dose virus administration increased neutrophil counts to 5660 +/- 930 cells/microl (mean +/- SD) and 4010 +/- 850 cells/microl, respectively, that were sustained for > 17 months and were significantly higher than controls counts of 1890 +/- 570 cells/microl (p< or =0.0002). Rats treated with EPO-virus produced significantly increased hematocrits (HCT) (63.1 +/- 4.3% vs. 46.0 +/- 3.2%, p < 0.0001) without effect on G-CSF-virus-mediated neutrophil production. Antivirus antibodies were not detectable at serum dilutions > or =1:10 by virus neutralization or ELISA. Lymphocytes and platelets were not significantly different between control and treated animals (p > 0.1). Only genomic DNA from muscle at injection sites was positive for provirus suggesting lack of virus spread.

CONCLUSIONS

G-CSF-lentivirus administered IM provided elevated, sustained neutrophil counts that were unchanged by subsequent EPO-lentivirus administration. Significantly increased hematocrits were obtained following EPO-lentivirus delivery. These data support the treatment of patients with severe chronic neutropenia by dosed lentivirus delivery IM.

An adult dog with cyclic neutropenia treated by lentivirus- mediated delivery of granulocyte colony-stimulating factor

Cyclic neutropenia occurs in humans and gray collie dogs, is characterized by recurrent neutropenia, and is treated by daily injections of recombinant granulocyte colony-stimulating factor (G-CSF). After showing that canine recombinant G-CSF increased neutrophil counts in an affected dog, we administered intramuscularly 2 x 10(9) infectious units (IU) of a lentiviral vector encoding canine G-CSF cDNA. Elevated, therapeutic neutrophil production was obtained for nearly 18 months. Lentiviral vector treatment provided a mean neutrophil count of 29,230 +/- 12,930 cells/microl, which was significantly increased over both the pretreatment value (5,240 +/- 4,800 cells/microl; p < 0.0001) and the neutrophil count during G-CSF administration (17,820 +/- 11,100 cells/microl; p < 0.0001). By systemic infusion of recombinant G-CSF to normal dogs we estimated that 2 x 10(9) IU of lentivirus delivered 3.5 microg of G-CSF per kilogram per day. After lentiviral vector treatment the gray collie gained weight, showed no clinical signs of infection and fever, and no longer needed housing in a pathogen-free environment. Genomic DNA harvested from muscle at the injection sites was positive for provirus, whereas gonad, lung, spleen, heart, liver, kidney, and noninjected muscle samples were negative. These studies show that an adult animal is responsive long-term to lentivirus-mediated G-CSF delivery, suggesting this approach may be applied for treatment of adult patients with cyclic and other neutropenias.

Sustained elevation of neutrophils in rats induced by lentivirus-mediated G-CSF delivery

BACKGROUND

Patients with severe chronic and cyclic neutropenia, characterized by neutrophil numbers <500 cells/microl, are treated daily with recombinant granulocyte colony-stimulating factor (G-CSF). As an alternative delivery approach we investigated the ability of lentivirus vectors to provide sustained G-CSF expression.

METHODS

Fischer rats were injected intramuscularly (IM) with vesicular stomatitis virus G (VSV-G)-pseudotyped lentivirus pRRL-CMV-G-CSF-SIN that encoded rat G-CSF cDNA regulated by the human cytomegalovirus (CMV) promoter and incorporated a self-inactivating (SIN) construct in the 3' long terminal repeat (LTR). Control rats received normal saline or lentivirus encoding the enhanced green fluorescent protein (eGFP). Rats were serially monitored for blood cell production and tissues assayed for provirus distribution.

RESULTS

Rats receiving a single IM injection of lentivirus exhibited elevated neutrophil counts for 14 months. Virus administration of 6 x 10(7) infectious units induced sustained levels of neutrophil production having a mean +/- standard deviation (SD) of 5650 +/- 900 cells/microl and rats that received a 10-fold lower dose of virus showed mean neutrophil counts of 3340 +/- 740 cells/microl. These were significantly higher than the mean of control animals receiving saline or control lentivirus (1,760 +/- 540 cells/microl, P < 0.0001). White blood cell (WBC) counts were significantly elevated in treated over control animals (P < 0.0001). Hematocrits (P > 0.3), lymphocytes (P > 0.2) and platelets (P > 0.1) were not significantly different between control and treated animals. Genomic DNA from muscle at the injection sites was positive for provirus, whereas lung, spleen, liver, kidney and non-injected muscle samples were all negative, suggesting lack of virus spread.

CONCLUSIONS

These studies indicate that lentivirus vectors administered IM provide sustained, therapeutic levels of neutrophils and suggest this approach to treat patients with severe and cyclic neutropenia.

Continuous pentobarbital infusion in children is associated with high rates of complications

PURPOSE

To evaluate the incidence and severity of complications related to continuous pentobarbital (PB) infusion for sedation in the Pediatric Intensive Care Unit (PICU).

MATERIALS AND METHODS

We conducted a retrospective, chart review study. All patients admitted to the PICU from January 1997 through June 1998 who received continuous IV PB infusion for sedation (n = 8) were included.

RESULTS

All patients were intubated and mechanically ventilated prior to PB infusion. PB was used only as a second line sedative after a combination of an opioid and benzodiazepine failed to achieve adequate sedation. After initiation of PB, we were able to decrease or discontinue benzodiazepines and/or opioid doses and discontinue neuromuscular blocking drugs in all patients. We observed a high incidence of complications (62.5%) related to PB or the phenobarbital treatment used for barbiturate weaning, including blood pressure instability (25%), oversedation (12.5%), drug reaction (12.5%) and neurologic sequelae (12.5%). Discontinuation of the drug was required in 25% of the cases.

CONCLUSIONS

We found continuous PB infusion to be an effective sedative for children when other drugs fail. However, we observed a high rate of clinically significant complications requiring discontinuation of the drug.

Long-Term Erythropoietin Gene Expression from Transduced Cells in Bioisolator Devices

Recombinant erythropoietin (EPO) is widely administered for long-term treatment of anemia associated with renal failure and other chronic diseases. The ability to deliver EPO by gene therapy would have clinical and economic benefit. We compared autologous and allogeneic transduced primary vascular smooth muscle cells for their ability to provide sustained EPO gene expression when encapsulated in TheraCyte devices implanted subcutaneously (SQ) or intraperitoneally (IP) in rats. Cells were transduced with retrovirus vector LrEpSN encoding rat EPO cDNA. Rats that received either autologous or allogeneic transduced cells showed elevated hematocrits (HCTs) ranging from 50 to 79% that were sustained for more than 12 months. The HCT of control rats remained at baseline (45.8%). Rats that received second SQ implants of either autologous or allogeneic cells showed elevations in hematocrit that were sustained for up to 12 months, suggesting the absence of immunological responses to transduced cells or implant material. All experimental groups had statistically significant elevated HCT (p < 0.001) when compared with controls. Both SQ and IP implantation were equally effective in delivering EPO long term. There were no significant differences in white blood cell (WBC) or platelet (PLT) values between treated and control animals. Implantation of TheraCyte devices was well tolerated and histological evaluation of the devices up to 12 months after surgery revealed a high degree of vascularization and no evidence of host immune response. TheraCyte devices offer a simple and safe gene delivery system that provides sustained therapeutic gene expression, permit removal and implantation of new devices, and do not require immunosuppression of the host.

Treatment of canine cyclic neutropenia by lentivirus-mediated G-CSF delivery

Cyclic neutropenia is a rare disease that occurs both in humans and gray collie dogs and is characterized by recurrent severe neutropenia leading to bacterial infections and shortened life expectancy. Daily injections of recombinant granulocyte colony-stimulating factor (rG-CSF) are effective in shortening the period of severe neutropenia and reducing infections. After demonstrating that rG-CSF induced elevated neutrophil production in an affected dog, cytokine administration was stopped and 109 infectious units (IUs) of a lentivirus pseudotyped with vesicular stomatitis virus G protein (VSV-G) encoding canine G-CSF cDNA was administered intramuscularly. Serial blood cell counts showed elevated neutrophil production for longer than 17 months. Although neutrophil counts continued to cycle, the range at nadirs was from 3710 to 5300 cells/microL, well above the nadirs before lentivirus administration. After the injection of lentivirus, mean neutrophil counts +/- SD were 12 460 +/- 4240 cells/microL, significantly increased over both pretreatment values of 3040 +/- 2540 cells/microL(P <.0001) and neutrophil counts during G-CSF administration of 10 290 +/- 4860 cells/microL(P <.007). The changes in blood counts from lentivirus injection were associated with absence of clinical signs of infection and fever. The gray collie continued to gain weight and was no longer housed in a pathogen-free environment. Genomic DNA from muscle at injection sites was positive for provirus, whereas gonad, lung, spleen, heart, liver, kidney, leukocytes, and noninjected muscle samples were all negative for provirus. Thus, intramuscular administration of lentivirus encoding G-CSF provided sustained therapeutic levels of neutrophils, suggesting this approach may be applied for long-term treatment of patients with cyclic and other neutropenias.

Retained wooden foreign body in a child's thigh complicated by severe necrotizing fasciitis: a case report and discussion of imaging modalities for early diagnosis

Soft tissue foreign bodies (FB) represent a common cause for emergency department visits. Diagnosis may be difficult especially with non-radiopaque FB. The clinical course may be complicated by superficial or deep tissue infection. Use of imaging modalities such as ultrasound may be important for early diagnosis. We report a case of retained foreign body with a complicated clinical course and discuss imaging modalities that may have aided in the early diagnosis.