Effect of lung fluid composition on type II cellular activity after tracheal occlusion in the fetal lamb.

BACKGROUND/PURPOSE: Fetal tracheal occlusion (TO) causes accelerated lung growth. However, prolonged TO is associated with a decline in the type II cell number. Type II cell function after TO is unclear. Herein, the authors examine type II cell function after TO and the role of tracheal fluid. METHODS: Fetal lambs (term, 145 days) underwent TO at 122 days. Tracheal pressure was recorded daily. In one group of animals (TF; n = 6), lung fluid was aspirated, measured, and reinfused daily. In their respective twins, NS group, lung fluid was replaced milliliter per milliliter with normal saline (NS; n = 6). At death near term, lung weight was obtained, and tissues were processed for stereologic volumetry. Type II cells were quantitated using antisurfactant protein B immunohistochemistry. Surfactant protein B-mRNA expression was studied by Northern analysis. Wilcoxon signed rank test and single factor analysis of variance (ANOVA) were used for statistical analysis (P<.05 was significant). RESULTS: In both experimental groups, intratracheal pressure rose from 1.9+/-1.0 torr to 3.7 to 4.8 torr by day 1, and remained constant thereafter. Lung fluid volume increased from 11.9+/-4.2 on day 0 to 36.8+/-8.0 mL/kg in TF, and to 28.4+/-9.3 mL/kg in NS by day 1 (P<.05). At death, lung weight/body weight ratio was higher in TF (5.45% +/- 0.91%) than in NS (4.40% +/- 0. 67%) or control (3.83%+/-0.58%; P<.05). Type II numerical density was substantially reduced after TO: 57.7+/-12.8 x 10(6)/mL (TF) and 45.0 +/-25.9 x 10(6)/mL (NS), versus 82.3+/-13.6 x 10(6)/mL in controls. Ultrastructurally, remaining type II cells in TF were enlarged and engorged with lamellar bodies; in NS, they were smaller and contained fewer lamellar bodies. Surfactant protein B mRNA expression was significantly decreased in NS, but not in TF, compared with controls. CONCLUSIONS: Type II cell function as well as overall lung growth are stimulated by TO. Lung growth after TO is therefore not unavoidably detrimental to type II cells. After isobaric saline exchange of lung fluid, type II cell function is severely inhibited, confirming the role of tracheal fluid composition in type II stimulating type II cell function.

Institutional Review Board approval for prospective experimental studies on infants and children.

BACKGROUND/PURPOSE: The Declaration of Helsinki requires Institutional Review Board (IRB) approval for experimental studies on human subjects. The authors questioned whether published prospective surgical experimental studies document IRB approval for infants and children. METHODS: Prospective studies were identified in 5 surgical and 2 major pediatric journals from 1997 through 1999. Documentation of IRB approval was recorded. Results were analyzed using Pearson chi(2) tests and a multivariate regression model. Statistical significance was defined as P less than .05. RESULTS: A total of 149 prospective experimental studies on pediatric subjects were evaluated; the majority being interventional or therapeutic studies (105 of 149). More than 75% were from academic medical centers (125 of 149), grant-supported (110 of 149), and appeared in surgical journals (110 of 149). Slightly less than 25% of studies (40 of 149) documented IRB approval. Observational studies, grant support, and publication in nonsurgical journals all correlated positively with IRB approval and were statistically significant variables (P<.001, P<.001, P<.001, respectively). Interventional or therapeutic, institutionally or privately-funded studies found in surgical journals were most likely to avoid IRB documentation (P<.001). CONCLUSIONS: The majority of prospective pediatric studies in the surgical journals omit IRB documentation. Strict requirements for specific IRB approval and documentation in compliance with the Declaration of Helsinki would allow higher ethical standards for the clinical investigation of infants and children.

Macrophage phenotype during cholestatic injury and repair: the persistent inflammatory response.

BACKGROUND/PURPOSE: Biliary decompression for congenital or acquired obstruction (eg, biliary atresia) does not uniformly lead to liver repair, restore function, or prevent cholangitis. The authors hypothesize that failed repair is caused by altered macrophage (Mo) phenotypes central to an ongoing inflammatory and fibrogenic response. METHODS: In adult rats, biliary obstruction was performed by suspension of the common bile duct for 5 or 7 days. Decompression followed release of the loop until death during the course of liver repair. To determine Mo phenotype in the presence or absence of resident macrophages, animals were either administered gadolinium chloride or saline before injury and repair. At death, hepatic Mo were isolated, stained with MAC-1 (CD11b/CD 18) and OX-3 (MHC class II), and quantified with flow cytometry. Liver sections were immunostained for ED-1 and ED2; positive Mo were counted per square millimeter of tissue. RESULTS: Obstruction led to bile duct proliferation, fibrosis, and inflammation. Decompression relieved jaundice and ductal hyperplasia. After injury, hepatic Mo showed an 80% phenotypic conversion to MAC-1 and OX-3-positive cells. Cells isolated from livers at 9 days of repair persisted with 60% MAC-1 and 77% OX-3 expression. Gadolinium reduced Kupffer cells at all stages of repair. Recruited Mo in treated animals increased 4-fold greater than controls. CONCLUSIONS: Kupffer cells appear to limit the recruitment and persistence of a systemic macrophage phenotype in liver injury and repair. Cell surface markers for systemic macrophages appear after injury and persist during repair, despite adequate biliary decompression. After biliary decompression, this macrophage phenotype accounts for inflammatory complications such as cholangitis and ongoing fibrosis.

Kupffer cell inactivation delays repair in a rat model of reversible biliary obstruction.

BACKGROUND: During cholestatic liver injury, Kupffer cells (KC) and activated macrophages modulate cell proliferation and subsequent matrix deposition. The role of KC in the restoration of cell architecture and matrix metabolism during repair following chronic cholestatic liver injury is unknown. MATERIALS AND METHODS: To determine the effect of KC inactivation, adult male Sprague-Dawley rats underwent bile duct suspension (BDS) for 5 days followed by reversal of the obstruction. Saline (control) and gadolinium chloride (10 mg/kg) were administered 1 day prior to BDS and 1 day prior to reversal, to inactivate KC during both injury and repair. Serum bilirubin and quantitative cell morphometry were compared to verify the reversibility of the model. Collagen content of the liver was measured in trichrome-stained paraffin sections using NIH imaging software. RESULTS: Reversibility of the obstruction was verified by normalization of direct serum bilirubin, which peaked at 8.42 +/- 0.76 mg/dL following 5 days of BDS and returned to sham-operated levels 2 days after reversal, 0.36 +/- 0.15 mg/dL. Hematoxylin and eosin (H&E)-stained paraffin-embedded liver sections from gadolinium-treated animals at 4 and 7 days after reversal exhibited persistent bile duct proliferation, matrix deposition, and inflammation. Gadolinium-treated animals had altered collagen metabolism compared to saline controls. Whereas the collagen content in the saline group slowly returned to sham-operated levels over time, the treatment group demonstrated progressive accumulation of collagen during repair which was statistically significant at 7 days following reversal (8.79%/mm(2) +/- 2.17 in gadolinium group vs 2. 33%/mm(2) +/- 0.34 in saline group, P = 0.0003). CONCLUSIONS: These results demonstrate that inactivation of resident hepatic macrophages during liver repair impairs collagen metabolism, inhibits the resolution of fibrosis, and allows the persistence of inflammatory cell infiltrates in the portal areas. This is the first evidence of profibrogenic responses in the absence of an intact KC compartment during repair after cholestatic injury.

The unpredictable character of congenital cystic lung lesions.

BACKGROUND: The spectrum of congenital cystic disease of the lung ranges from hydrops and neonatal respiratory distress to asymptomatic lesions. Surgical management is dictated by the presence of symptoms, recurrent infection, and the potential risk of malignant transformation. METHODS: Since 1995, all consecutive patients with congenital cystic lung lesions underwent follow-up for symptoms, treatment, and correlation of presumptive with pathological diagnosis. RESULTS: Twelve cystic lung lesions were identified. Seven were diagnosed with mediastinal shift in utero; in 6 of 7, the shift subsequently resolved. Overall, 6 of 7 lesions that were followed up serially decreased in size. Two patients were symptomatic in utero; 1 underwent thoracoamniotic shunting, 1 pleurocentesis for impending hydrops. Postnatally, these 2, and 2 other newborns required urgent surgery. Five of 8 asymptomatic patients had elective resection by 16 months, and 4 await operation. In 6 of the 9 surgical cases (67%), there was a discrepancy between preoperative and pathological diagnosis. There were 4 hybrid congenital cystic adenomatoid malformation (CCAM)/sequestrations. CONCLUSIONS: At least 6 of 7 congenital cystic lung lesions decreased in size regardless of gestational age or presence of mediastinal shift. Antenatal intervention is therefore rarely indicated. Hybrid morphology may necessitate resection of stable, asymptomatic lesions to prevent the theoretical concern for associated malignancies as well as other complications of CCAM.

Subcutaneous forearm transplantation of autologous parathyroid tissue in patients with renal hyperparathyroidism.

BACKGROUND: Parathyroidectomy is required in up to 5% of patients with chronic renal failure. Intramuscular transplantation of autologous parathyroid tissue in the forearm has been the traditional method of transplantation at the time of total parathyroidectomy. The removal of an intramuscular transplantation can be technically difficult should graft-dependent hyperparathyroidism (GRH) occur. This problem resulted in our initiating a study of subcutaneous transplantation with total parathyroidectomy in patients with renal failure. METHODS: Twenty-six patients who were receiving dialysis therapy underwent total parathyroidectomy and subcutaneous transplantation. Parathyroid tissue was diced into 1- to 2-mm pieces, and 6 pieces were grafted into 6 subcutaneous pockets of the forearm. Intact parathyroid hormone was measured within 48 hours of operation and in the bilateral antecubital veins 1 to 24 months after the operation to assess completeness of resection and graft function, respectively. RESULTS: No major surgical complications occurred. Symptoms improved in 24 patients (85%). Graft failure rate was 4.3%. No GRH was observed. Follow-up was 4 to 55 months (mean, 27 months). CONCLUSIONS: This study indicates that the subcutaneous transplantation function is comparable to intramuscular transplantation and suggests a decreased incidence of GRH. Subcutaneous transplantation is technically easier than intramuscular transplantation and has the additional advantage of easy removal should GRH occur.