Endovascular model of rabbit hindlimb ischemia: a platform to evaluate therapeutic angiogenesis

PURPOSE: Current animal hindlimb ischemia models involve surgical ligation of the femoral artery and delivery of therapeutic angiogenic agents into the adductor compartment. The authors hypothesize that an endovascular model of hindlimb ischemia would be a more appropriate platform, closely resembling atherosclerosis by occluding the vessel from within, causing less inflammation, wound healing and subsequent collateralization. MATERIALS AND METHODS: The left superficial femoral artery in 17 rabbits was occluded by endovascular coil embolization (n=9) or surgical ligation (n=8). Animals (n=3; in each group) were sacrificed on day 3 to determine the arteriolar luminal area, number of arterioles, microsphere determined perfusion, and degree of inflammation. On day 28, the remaining animals underwent calf blood pressure measurements and angiography to determine the number of collaterals and diameter of vessels supplying the hindlimb. RESULTS: Immediate postprocedure (day 0) and presacrifice (day 3 or 28) occlusion rates were 89% (eight of nine rabbits) and 100% for the endovascular model; 100% and 100% for the surgical model, respectively. Hindlimb paralysis and muscle atrophy was found in one surgical animal. On day 3, there was an increase in hindlimb perfusion (surgery, 0.04+/-0.01; endovascular, 0.02+/-0.01; P=.02), an increase in arteriolar luminal area (surgery, 481 microm+/-240; endovascular, 345 microm+/-151; P=.04), and a trend toward more inflammation (surgery, 5.5+/-3.8; endovascular, 2.5+/-3.0; P=.08) in the surgical group. There was no difference in number of vessels between both groups. On day 28 there was no difference in the calf blood pressure ratios or in the number of collaterals. However, there was enlargement of the distal profunda femoris artery, the vessel closest to the surgical incision, in the surgical group (L/R ratio: immediate post-occlusion, 1.06+/-0.11; day 28, 1.27+/-0.08; P=.02). CONCLUSION: The endovascular model was efficacious in providing occlusion of the superficial femoral artery, and induced less of an arteriogenic response compared with the surgical model. The authors believe that this endovascular model is a superior platform for studying therapeutic angiogenic agents.     

A U.S. Army Forward Surgical Team's experience in Operation Iraqi Freedom

BACKGROUND: The Forward Army Surgical Team (FST) was designed to provide surgical capability far forward on the battlefield to stabilize and resuscitate those soldiers with life and limb threatening injuries. Operation Iraqi Freedom represents the largest military operation in which the FST concept of health care delivery has been employed. The purpose of our review is to describe the experience of the 555FST during the assault phase of Operation Iraqi Freedom. METHODS: During the 23 days beginning 21 March 2003, data on all patients seen by the 555 FST were recorded. These data included combatant status, injuries according to anatomic location, and operative procedures performed. RESULTS: During the twenty-three day period, the 555 FST evaluated 154 patients. There were 52 EPWs, 79 U.S. soldiers, and 23 Iraqi civilians treated. Injuries to the lower extremity and chest (48% and 25%) were the most common in the EPW group. Upper extremity and lower extremity injuries were the most common in the civilian (57% and 39%) and U.S. soldier groups (32% and 30%). The number of injured regions per patient were 1.14 for U.S. soldiers, 1.33 for EPWs, and 1.52 for Iraqi civilians (p < 0.003). EPWs had proportionately more thoracic and abdominal injuries than the other groups (p < 0.05). CONCLUSIONS: Majority of the life threatening injuries evaluated involved EPWs. A combination of body armor and armored vehicles used by U.S. soldiers limited the number of torso injuries presenting to the FST. Early resuscitation and stabilization of U.S. soldiers, EPWs, and civilians can be successfully accomplished at the front lines by FSTs. Further modification of the FST's equipment will be needed to improve its ability in providing far forward surgical care.     

Cell-cycle regulatory proteins in podocyte cell in idiopathic nephrotic syndrome of childhood

BACKGROUND: The podocyte cell is believed to play an important role in idiopathic nephrotic syndrome (INS) of childhood. In adults with cellular and collapsing focal segmental glomerulosclerosis (FSGS), the expression of cell-cycle regulatory proteins such as p27, p57, and cyclin D is decreased and expression of cyclin A, Ki-67, and p21 is observed in podocyte cells suggestive of a dysregulated podocyte phenotype. We investigated for alterations in the expression of cyclin kinase inhibitors, p27, p57, p21, and cyclins D and A in the podocyte cell of children with INS. METHODS: Forty-two kidney biopsies were investigated; 14 with minimal-change disease (MCD), seven with diffuse mesangial hypercellularity (DMH), 12 with FSGS, four with Alport syndrome (AS), and five normal biopsies. The sections were examined by immunohistochemistry using dual staining method. Podocyte cells were first identified by Wilm's tumor-1 staining after which expressions of cell-cycle regulatory proteins were analyzed. A quantitative analysis was performed for the proportion of podocyte cells that expressed each cell cycle regulatory protein. RESULTS: On light microscopy, all podocyte cells expressed p27, while p57 and p21 expression was seen in a portion of podocyte cells in normal kidney biopsies. Cyclin D was expressed in a small percent of podocyte cells though the expression was more marked in mesangial and endothelial cells. Cyclin A expression was not seen in normal biopsies. The mean expression of p27 decreased significantly in order from normal (100%), MCD (45.9%), DMH (22.4%), and FSGS (16.7%), and the difference between MCD and FSGS was significant. p21 was significantly and equally reduced in MCD (2.3%), DMH (0%), and FSGS (0.7%) compared to normal (66.6%). There was no significant difference in expression of p57, cyclin D and cyclin A in the podocyte cells between normal and children with INS. Children with AS showed a significant decrease in p27 and p21 expression, while the expression of p57, cyclin D and cyclin A were unchanged from normal, thus demonstrating a pattern similar to INS. CONCLUSION: The podocyte cell in children with INS down-regulates expression of cyclin kinase inhibitors such as p21 and p27, but not p57, but does not up-regulate cyclin D and cyclin A that are needed to overcome the G1/S transition and move the cell forward in the cell cycle process. Thus, the podocyte cell remains trapped in the G1 arrest phase. In children with INS or AS, the dysregulated podocyte phenotype is different than the one described in adults with cellular or collapsing FSGS.     

The role of bisphosphonates in diseases of childhood

Bisphosphonates are synthetic analogues of pyrophosphate that inhibit bone resorption by their action on osteoclasts. In recent years, bisphosphonates have been used in children for treatment of a growing number of disorders associated primarily with generalized or localized osteoporosis, metabolic bone diseases, heterotopic calcification in soft tissues, and for resistant hypercalcemia. In the present review we discuss the pharmacological aspects of bisphosphonates and related bone pathophysiology, review the pediatric literature on the role of bisphosphonates in childhood diseases and our experience with these drugs. The theoretical concerns of possible adverse effects of these drugs on the growing skeleton have not materialized in the limited pediatric clinical experience. Bisphosphonates provide the pediatrician with an opportunity to treat mineral and bone disorders of childhood which until recently did not have satisfactory therapy, at the same time, being aware of the theoretical concerns on microdamage accumulation in bone, bone quality and teratogenic potential of these drugsSupported by the Sam and Helen Kaplan Research Fund in Pediatric Nephrology     

High incidence of focal segmental glomerulosclerosis in nephrotic syndrome of childhood

In recent adult literature, there have been reports of an increasing incidence of focal segmental glomerulosclerosis (FSGS) among patients with nephrotic syndrome. To examine whether this observation is also relevant to the pediatric population we utilized our hospital computerized database to analyze the data on children with primary nephrotic syndrome seen first between the years 1984 and 1995. A questionnaire was also sent to all metropolitan Kansas City pediatricians to identify possible patients outside the database. The inclusion criteria were clinical nephrotic syndrome or proteinuria with a kidney biopsy. A total of 148 patients (group A) were identified; 86 of them from metropolitan Kansas City (group B). In group A the incidence of minimal change disease (MCD) and FSGS was 52.7% [95% confidence interval (CI) 44%-60%] and 23.0% (95% CI 16-29%), respectively and in group B 54.7% (95% CI 44%-65%) and 24.5% (95% CI 15%-33%), respectively. Those numbers were significantly different from the International Study of Kidney Disease in Children (IS-KDC) reported incidence of 76.4% for MCD and 6.9% for FSGS. Similar to the ISKDC, in our population children over 6 years had a higher incidence of FSGS than younger children (32.8% vs. 16.7%, P = 0.028). The annual incidence rate for nephrotic syndrome in group B was 2.2 cases/10(5) children per year, of which MCD comprised 1.22 cases/10(5) children per year and FSGS 0.5 cases/10(5) children per year. The annual incidence rates of both primary nephrotic syndrome (3.6) and FSGS (1.6) were significantly higher in African-Americans, than Caucasians (1.8 and 0.3 cases/10(5) children per year, respectively). Our study indicates nearly no change in the annual incidence of pediatric primary nephrotic syndrome, but a higher incidence of FSGS with reciprocal decline in the incidence of MCD. The possibility of primary nephrotic syndrome being caused by a non-MCD entity is further raised among African-American and in children over 6 years. We conclude that our perception of primary nephrotic syndrome of childhood as a benign condition has to be carefully reexamined and a more-guarded prognostic approach adopted in our geographic area.     

Cinacalcet as adjunctive therapy in pseudohypoparathyroidism type 1b

Background

In patients with pseudohypoparathyroidism type 1b (PHP1b) due to a tissue-specific imprinting defect in the G-protein α-subunit, skeletal disorders can arise from the bones being sensitive to parathyroid hormone (PTH) while the kidneys remain resistant to this hormone.

Case-diagnosis/treatment

We report a 4.8-year-old girl with PHP1b who presented with an abnormal gait, severe skeletal changes and elevated levels of serum PTH (2844 pg/ml), phosphate (7.2 mg/dl) and bone turnover markers. Traditional treatment with calcium and calcitriol failed to suppress PTH secretion, which was still elevated at 2877 pg/ml after 14 months of therapy, nor did it correct the other clinical, biochemical and radiographic abnormalities. The addition of cinacalcet to the treatment regimen over the subsequent 32 months resulted in normalization of serum PTH (58 ng/ml), phosphate (4.9 mg/dl) and bone turnover markers, and resolution of the radiographic changes, with no adverse effects noted.

Conclusions

Due to its ease of administration, we recommend the addition of cinacalcet into the armamentarium of medications available to treat children with PHP1b.

     

Blood brain barrier (BBB) dysfunction associated with increased expression of tissue and urokinase plasminogen activators following peripheral thermal injury

Emerging data suggests the serine proteases, tissue plasminogen activator (tPA), and urokinase plasminogen activator (uPA), may play a detrimental role in traumatic states leading to compromise of the blood brain barrier (BBB). The purpose of our study was to define the role of endogenous tPA and uPA on the BBB following peripheral burn injuries. Adult male Sprague–Dawley rats (n = 46) were studied in control and thermal injury groups. Rats were anesthetized and submerged in 100 °C water for 6 s producing a third degree burn affecting 60–70% of the total body surface area. BBB dysfunction was then evaluated by measuring the amount of Evans blue and by calculating the water content in the brain. Levels of tPA and uPA mRNA in the brain were determined with real-time polymerase chain reaction (PCR) at 3 and 7 h post-injury. Results showed an increase in the brain water content and the presence of Evans blue in the brain tissue of thermally injured rats, temporally associated with an increased expression of endogenous tPA and uPA. Our study demonstrates that peripheral thermal injury does induce an increase in the permeability of the BBB. A possible mechanism may be an increased expression of tPA and uPA.     

Salpingectomy - the laparoscopic surgical choice for ectopic pregnancy

The aim of this study was to assess the fertility outcome afterectopic pregnancy (EP) treated by laparoscopic salpingectomy.Among the 375 patients who underwent this operation betweenJanuary 1983 and December 1993, there were 145 patients whodesired pregnancy and whose contralateral tube was not obstructed.The overall rate of intrauterine pregnancy (IUP) was 50.3%,with an EP rate of 15.2%, These results were analysed accordingto the patients‘ past history together with the conditionof the contralateral tube at the time of the laparoscopy. Wedefined two groups. Group 1 included patients who had no previoushistory of tubal surgery and whose contralateral tube was normal.Group 2 comprised those patients who had a previous historyof tubal surgery and/or those whose tube was pathological, butnot obstructed. Postoperative fertility of the patients in group1 was significantly higher than that of the patients in group2, with IUP rates of 75 and 36.6% respectively (P < 0.001),and a risk of EP recurrence of 9.6 and 183% respectively. Ingroup 1, the actuarial IUP rate at 24 months was significantlyhigher than that for the patients in group 2 (66.7 versus 36.9%;P < 0.001). The patient’s past history and the conditionof the contralateral tube were the two major factors relatedto fertility outcome after laparoscopic salpingectomy for EP.In patients with no past history of tubal surgery or infertilityand whose contralateral tube was normal, the fertility resultsafter laparoscopic salpingectomy appeared comparable to thoseobserved after conservative laparoscopic treatment     

Impact of standardization of creatinine methodology on the assessment of glomerular filtration rate in children

There is a global effort to standardize clinical laboratory serum creatinine measurements to the reference method of isotope-dilution mass spectrometry (IDMS). Creatinine values in serum and urine are frequently used in children to calculate creatinine clearance (mCrCl) or estimate glomerular filtration rate (GFR) by Schwartz's equation (eGFR). The original normative data of mCrCl and eGFR were developed using Jaffe method. To investigate what impact the differences in methodologies of creatinine analysis will have on mCrCl and eGFR, we measured creatinine in random serum and urine samples by three commercially available assays: Jaffe (J), enzymatic (E) and enzymatic method traceable to IDMS (E-IDMS). There was a significant bias in the two enzymatic methods when compared with J method. The theoretical predicted errors in overestimating mCrCl ranged from 1.10 to 1.34 by E and 1.20 to 1.54 by E-IDMS; and in calculating eGFR 1.07-1.16 by E and 1.30-1.46 by E-IDMS, which was further confirmed in children who had formal GFR evaluation. Thus, as the clinical laboratories calibrate their creatinine assays to the gold standard IDMS method, it is important for the pediatric nephrology community to develop new equations for estimation of GFR based on the new creatinine assay.