Persistent Brain Connectivity Changes in Healthy Volunteers Following Nitrous Oxide Inhalation

Background

Nitrous oxide holds promise in the treatment of major depressive disorder. Its psychotropic effects and NMDA receptor antagonism have led to comparisons with ketamine. Despite longstanding use, persistent effects of nitrous oxide on the brain have not been characterized.

Methods

Sixteen healthy volunteers were recruited in a double-blind crossover study. In randomized order, individuals underwent a 1-hour inhalation of either 50% nitrous oxide/oxygen or air/oxygen mixtures. At least two 7.5-minute echo-planar resting-state functional magnetic resonance imaging scans were obtained before and at 2 and 24 hours after each inhalation (average 130 min/participant). Using the time series of preprocessed, motion artifact-scrubbed, and nuisance covariate-regressed imaging data, interregional signal correlations were measured and converted to T scores. Hierarchical clustering and linear mixed-effects models were employed.

Results

Nitrous oxide inhalation produced changes in global brain connectivity that persisted in the occipital cortex at 2 and 24 hours postinhalation (p < .05, false discovery rate-corrected). Analysis of resting-state networks demonstrated robust strengthening of connectivity between regions of the visual network and those of the dorsal attention network, across 2 and 24 hours after inhalation (p < .05, false discovery rate-corrected). Weaker changes in connectivity were found between the visual cortex and regions of the frontoparietal and default mode networks. Parallel analyses following air/oxygen inhalation yielded no significant changes in functional connectivity.

Conclusions

Nitrous oxide inhalation in healthy volunteers revealed persistent increases in global connectivity between regions of primary visual cortex and dorsal attention network. These findings suggest that nitrous oxide inhalation induces neurophysiological cortical changes that persist for at least 24 hours.

Protection levels of N95-level respirator substitutes proposed during the COVID-19 pandemic: safety concerns and quantitative evaluation procedures

OBJECTIVE

The COVID-19 pandemic has precipitated widespread shortages of filtering facepiece respirators (FFRs) and the creation and sharing of proposed substitutes (novel designs, repurposed materials) with limited testing against regulatory standards. We aimed to categorically test the efficacy and fit of potential N95 respirator substitutes using protocols that can be replicated in university laboratories.

SETTING

Academic medical centre with occupational health-supervised fit testing along with laboratory studies.

PARTICIPANTS

Seven adult volunteers who passed quantitative fit testing for small-sized (n=2) and regular-sized (n=5) commercial N95 respirators.

METHODS

Five open-source potential N95 respirator substitutes were evaluated and compared with commercial National Institute for Occupational Safety and Health (NIOSH)-approved N95 respirators as controls. Fit testing using the 7-minute standardised Occupational Safety and Health Administration fit test was performed. In addition, protocols that can be performed in university laboratories for materials testing (filtration efficiency, air resistance and fluid resistance) were developed to evaluate alternate filtration materials.

RESULTS

Among five open-source, improvised substitutes evaluated in this study, only one (which included a commercial elastomeric mask and commercial HEPA filter) passed a standard quantitative fit test. The four alternative materials evaluated for filtration efficiency (67%-89%) failed to meet the 95% threshold at a face velocity (7.6 cm/s) equivalent to that of a NIOSH particle filtration test for the control N95 FFR. In addition, for all but one material, the small surface area of two 3D-printed substitutes resulted in air resistance that was above the maximum in the NIOSH standard.

CONCLUSIONS

Testing protocols such as those described here are essential to evaluate proposed improvised respiratory protection substitutes, and our testing platform could be replicated by teams with similar cross-disciplinary research capacity. Healthcare professionals should be cautious of claims associated with improvised respirators when suggested as FFR substitutes.

Quantitative Fit Tested N95 Respirator-Alternatives Generated With CT Imaging and 3D Printing: A Response to Potential Shortages During the COVID-19 Pandemic

Rationale and Objective

Three-dimensional (3D) printing allows innovative solutions for personal protective equipment, particularly in times of crisis. Our goal was to generate an N95-alternative 3D-printed respirator that passed Occupational Safety and Health Administration (OSHA)-certified quantitative fit testing during the COVID-19 pandemic.

Materials and Methods

3D printed prototypes for N95 solutions were created based on the design of commercial N95 respirators. Computed tomography imaging was performed on an anthropomorphic head phantom wearing a commercially available N95 respirator and these facial contour data was used in mask prototyping. Prototypes were generated using rigid and flexible polymers. According to OSHA standards, prototypes underwent subsequent quantitative respirator fit testing on volunteers who passed fit tests on commercial N95 respirators.

Results

A total of 10 prototypes were 3D printed using both rigid (n = 5 designs) and flexible materials (n = 5 designs), Prototypes generated with rigid printing materials (n = 5 designs) did not pass quantitative respirator fit testing. Three of the five prototypes with flexible materials failed quantitative fit testing. The final two prototypes designs passed OSHA-certified quantitative fit tests with an overall mean fit factor of 138 (passing is over 100).

Conclusion

Through rapid prototyping, 3D printed N95 alternative masks were designed with topographical facial computed tomography data to create mask facial contour and passed OSHA-certified quantitative respiratory testing when flexible polymer was used. This mask design may provide an alternative to disposable N95 respirators in case of pandemic-related shortages. Furthermore, this approach may allow customization for those that would otherwise fail fit testing on standard commercial respirators.

Measuring cerebral hemodynamics with a modified magnetoencephalography system

Magnetoencephalography (MEG) systems are designed to noninvasively measure magnetic fields produced by neural electrical currents. This project examines the possibility of measuring hemodynamics with an MEG system that has been modified with dc electromagnets to measure magnetic susceptibility while maintaining the capability of measuring neural dynamics. A forward model is presented that simulates the interaction of an applied magnetic field with changes in magnetic susceptibility in the brain associated with hemodynamics. Model predictions are compared with an experiment where deionized water was pumped into an inverted flask under the MEG sensor array of superconducting quantum interference device (SQUID) gradiometers (R(2) = 0.98, p < 0.001). The forward model was used to simulate the SQUID readouts from hemodynamics in the scalp and brain induced by performing the Valsalva maneuver. Experimental human subject recordings (N = 10) were made from the prefrontal region during Valsalva using concurrent measurement with the modified MEG system and near-infrared spectroscopy (NIRS). The NIRS deoxyhemoglobin signal was found to correlate significantly with the SQUID readouts (R(2) = 0.84, p < 0.01). SQUID noise was found to increase with the applied field, which will need to be mitigated in future work. These results demonstrate the potential and technical challenges of measuring cerebral hemodynamics with a modified MEG system.

Effect of deep breathing on extracted oxygen and cerebral hemoglobin levels

This study examines the relationship between oxygen expired and functional near infrared spectroscopy (fNIRS) measured hemoglobin levels in the brain. Analysis of these two signals during normal versus deep breathing provides insight into the dynamics of cerebral physiology. Intersubject variation suggests the existence of two distinct groups with respect to oxygen extraction and hemoglobin levels.

BCR-ABL: a multi-faceted promoter of DNA mutation in chronic myelogeneous leukemia

The role of the BCR-ABL oncogene in the progression of chronic myeloid leukemia (CML) to blast crisis (BC) is unknown. The appearance of chromosomal aberrations in patients with CML BC has led to many attempts to elucidate a mechanism whereby BCR-ABL affects DNA damage and repair. BCR-ABL-expressing cells have been found to accumulate genetic abnormalities, but the mechanism leading to this genomic instability is controversial. In this study, we review the effects of BCR-ABL on DNA repair mechanisms, centrosomes, checkpoint activation and apoptosis. BCR-ABL has diverse effects on these mechanisms, but which of these effects are necessary for the progression of CML to BC is still unresolved.

BCR/ABL induces chromosomal instability after genotoxic stress and alters the cell death threshold

Earlier reports have suggested that the BCR/ABL oncogene, associated with chronic myeloid leukemia, induces a mutator phenotype; however, it is unclear whether this leads to long-term changes in chromosomes and whether the phenotype is found in primary chronic myelogeneous leukemia (CML) cells. We have addressed both these issues. BCR/ABL-expressing cell lines show an increase in DNA breaks after treatment with etoposide as compared to control cells. However, although BCR/ABL-expressing cell lines have an equivalent cell survival, they have an increase in chromosomal translocations after DNA repair as compared to control cells. This demonstrates that BCR/ABL expression decreases the fidelity of DNA repair. To see whether this is true in primary CML samples, normal CD34+ progenitor cells and CML progenitor cells were treated with etoposide. CML progenitor cells have equivalent survival but have an increase in DNA double-strand breaks (DSBs). Spectral karyotyping demonstrates new chromosomal translocations in CML cells, but not normal progenitor cells, consistent with error-prone DNA repair. Taken together, these data demonstrate that BCR/ABL enhances the accumulation of DSBs and alters the apoptotic threshold in CML leading to error-prone DNA repair.

Delayed acute renal failure in post-transplant period in young children from unexplained etiology

This report describes six young children (5 male) who developed delayed acute renal failure (DARF) in the early post-kidney-transplant (Tx) period in the absence of acute rejection (AR) or other diagnosable conditions. These young children, aged 16.5 +/- 3.1 (12-21) months [mean +/- SD, (range)] and weighing 8.5 +/- 1.7 (7.1-11.4) kg received a primary renal Tx (5 living-related donor, 1 cadaver) between 1984 and 1992. Immunosuppression included prednisone, azathioprine, and Minnesota antilymphocyte globulin (MALG, n = 5); one patient received cyclosporine and no MALG. Initially, all patients had good urine output (UO). They became systemically ill and abruptly developed diminished UO on post-operative day (POD) 6.5 +/- 1 (4-8). DARF was accompanied by fever (39.1-40.4 degrees C, n = 6), thrombocytopenia (platelets < 100,000/mm3, n = 6), leukocytosis, or leukopenia (white cell count > 20,000/mm3, n = 4 or < 1,000/mm3, n = 1). Four patients had diarrhea. Three had ascites and one was surgically explored for suspected urinary leak. None showed significant urinary obstruction by renal ultrasound. Renograms showed intact blood flow. Renal biopsy showed tubular ectasia (n = 6), vascular congestion (n = 5), focal glomerular endothelial swelling (n = 4), and capillary thrombi (n = 3). None showed AR. Five patients required dialysis for 11 +/- 4 (7-15) days. All patients survived. One patient, treated for suspected AR with the monoclonal antibody OKT3, developed shock and lost her graft on POD 12 due to vascular thrombosis. Renal functional recovery in the remaining five patients took 14 +/- 5 (6-20) days and their serum creatinine at discharge was 0.7 +/- 0.5 (0.3-1.6) mg/dl. We report DARF from undetermined etiology occurring in the first 2 weeks of renal Tx in young children. Treatment is supportive care including dialysis. Recognition of this complication will help avoid risky investigations or unnecessary treatment for rejection.

Recurrence of haemolytic-uraemic syndrome in renal transplants: a single-centre report

BACKGROUND

The incidence of recurrence of haemolytic-uraemic syndrome (HUS) in renal allografts appears to vary by centre, with the highest rates reported from the University of Minnesota. It is possible that the high rate of HUS recurrence at this institution reflects a transplant population skewed towards patients with a form of HUS that is more likely to recur in the allograft.

METHODS

This study examined whether the initial episode of HUS in the native kidneys was preceded by a diarrhoeal prodrome ('classical HUS') or not ('atypical HUS'), and evaluated transplant outcomes in 24 patients who received 36 transplants at the University of Minnesota between 31 May 1972 and 31 December 1994.

RESULTS

Eighteen of the 24 patients had atypical HUS, three had classical HUS, and in three patients the presence or absence of a diarrhoeal prodrome could not be determined. Recurrent HUS, defined as microangiopathic haemolytic anaemia, thrombocytopenia, renal insufficiency, and allograft biopsy findings compatible with HUS, occurred 16 times in 14 grafts in 11 patients. Nine of these patients had atypical HUS, one had classical HUS, and in one the nature of the prodrome could not be determined. Eleven of the 14 initial recurrences took place within 2 months of transplant. Recurrence was not more frequent in patients who received cyclosporin or antilymphocyte preparations. Actuarial analysis using matched controls showed poorer graft survival in patients with a primary diagnosis of HUS (P = 0.007), due to the high frequency of graft loss in HUS patients with recurrence.

CONCLUSION

Based upon these data and a review of the literature, it can be concluded that the risk of recurrence of HUS in the allograft is confined almost entirely to patients with atypical forms of HUS.

Chronic renal allograft rejection in the first 6 months posttransplant

Between May 1, 1986 and May 31, 1992 at the University of Minnesota, we interpreted 129 renal allograft biopsy specimens (done in 48 grafts during the first 6 months posttransplant) as showing changes consistent with chronic rejection. For this retrospective analysis, we reexamined these biopsies together with clinical information to determine: (a) whether a diagnosis other than chronic rejection would have been more appropriate, (b) how early posttransplant any chronic rejection changes occurred, and (c) if the diagnosis correlated with outcome. We found that (1) chronic rejection is uncommon in the first 6 months posttransplant; it was documented in only 27 (2.4%) of 1117 renal allografts and was preceded by acute rejection in all but 3 recipients (for these 3, the first biopsy specimen showed both acute and chronic rejection). (2) Chronic vascular rejection was seen in 1 recipient as early as 1 month posttransplant; the incidence increased over time and was associated with an actual graft survival rate of only 35%. (3) The most frequent cause of arterial intimal fibrosis in the first 6 months posttransplant was arteriosclerotic nephrosclerosis (ASNS) of donor origin. Long-term graft function for recipients with ASNS was 67%. (4) Early-onset ischemia or thrombosis was seen in 14 recipients and predicted poor outcome: only 35.7% of these recipients had long-term graft function. (5) Cyclosporine (CsA) toxicity was implicated in only 3 recipients, who had mild diffuse interstitial fibrosis in association with elevated CsA levels. Other variables (including systemic hypertension, urinary tract infection, obstructive uropathy, neurogenic bladder, cobalt therapy, and recurrent disease) were not significantly associated with chronic renal lesions in the first 6 months posttransplant. A significant number of biopsies were originally interpreted as showing chronic rejection, but the diagnosis was changed upon reevaluation in conjunction with clinical data. We conclude that many factors coexist to produce chronic lesions in biopsies during the first 6 months posttransplant, so clinical correlation is needed before establishing a diagnosis of chronic rejection.

Inherited factor H deficiency and collagen type III glomerulopathy

A non-immune complex-mediated glomerulonephritis associated with persistent hypocomplementemia occurred in a young boy. Measurement of complement components revealed complete factor H deficiency, inherited as an autosomal recessive trait. Evaluation of the renal lesion revealed extensive deposition of type III collagen suggestive of collagen type III glomerulopathy, a recently identified cause of chronic renal insufficiency in children and adults. This report represents the first association of inherited factor H deficiency with collagen type III glomerulopathy.

Antineutrophil cytoplasmic autoantibody-positive crescentic glomerulonephritis as a complication of treatment with propylthiouracil in children

Propylthiouracil, which is commonly used in the treatment of hyperthyroidism, has been associated in adults with antineutrophil cytoplasmic autoantibody, a serologic marker of vasculitis. Severe renal disease has not been reported as a complication of therapy with this drug. We report severe antineutrophil cytoplasmic autoantibody-positive vasculitis in children receiving propylthiouracil, as well as rapidly progressive crescentic glomerulonephritis after administration of this drug.

Juxtaglomerular body abnormalities in youth-onset diabetic subjects

Abnormal microalbuminuria in insulin-dependent diabetic subjects (IDDS) is significantly associated with pre-clinical nephropathy. In youth-onset IDDS declining plasma renin activity is significantly associated with improved albumin excretion, while persistently elevated renin activity is associated with continued abnormal microalbuminuria. To determine if these changes are reflected in changes in cell count in the juxtaglomerular body and if biopsy findings correlate with abnormal microalbuminuria, renal tissue of 20 IDDS (Study IDDS) ages 16 to 31 years, evaluated concurrently for plasma renin activity and microalbuminuria, were examined by light microscopy. Biopsy or autopsy specimens from 21 normal subjects and 32 IDDS (Non-Study IDDS), ages 2 to 25, were also examined. Specimens from the majority of prepubertal and all pubertal and postpubertal Non-Study IDDS and all Study IDDS independently of status of microalbuminuria had morphologic abnormalities. Normal or mesangially expanded glomeruli were found in association with expanded juxta-glomerular bodies and increased cell number, or with sclerotic bodies and decreased cell number. Sclerosis of juxtaglomerular bodies occurred independently of glomerular sclerosis. The highest percentage of glomeruli with expanded juxtaglomerular bodies and high cell count was present in specimens of Study IDDS with the most abnormal levels of microalbuminuria. T lymphocytes, noted within juxtaglomerular bodies, were present in specimens of 62% of the 52 Study and Non-Study IDDS. Abnormalities of the juxtaglomerular body are distinctive features of renal pathology in IDDS. T lymphocytes in the endocrine juxtaglomerular body suggest the presence of an autoimmune process. Confirmatory studies are necessary.

Disseminated malignant histiocytosis in a golden retriever: clinicopathologic, ultrastructural, and immunohistochemical findings

Diagnosis of malignant histiocytosis (MH), a disorder characterized by systemic proliferation of morphologically atypical histiocytes and their precursors, in an 8-year-old neutered female Golden Retriever was based on light and electron microscopic and immunohistochemical findings. Clinically, the dog presented with unilateral forelimb lameness. Eight days after surgical exploration of a swollen brachium, the dog developed sudden onset of posterior paresis, fecal and urinary incontinence, and a flaccid tail. Necropsy revealed infiltrative and nodular lesions in the right forelimb and regional lymph nodes, thoracic and abdominal cavities, and lumbar epidural space. Gross lesions were not found in the lungs or integument. Histopathologic examination showed infiltrates of atypical histiocytes in skeletal muscle, joint, and regional lymph nodes of the right forelimb; intercostal muscle; lung; liver; spleen; pancreas; kidneys; and spinal dura. Most tumor infiltrates were nodular and composed of loosely aggregated cells that were 10-30 microns in diameter with abundant eosinophilic to foamy cytoplasm, had central or eccentric nuclei, and were periodic acid-Schiff negative. Many binucleated cells, multinucleated giant cells, and mitotic figures were seen. Tumor cells contained phagocytosed erythrocytes, mononuclear cells, and some leukocytes. Ultrastructural features of tumor cells included cytoplasmic lipid droplets, lysosomes, and phagolysosomes. Immunohistochemical studies on paraffin-embedded sections showed positive reactivity to human T-cell Ag (clone UCHL-1) and for lysozyme, alpha-1-antitrypsin, and cathespin B. Polyclonal intracellular immunoglobulin reactivity and lectin binding (peanut, soybean, and wheat germ agglutinins and concanavalin A) were also demonstrated. Criteria for diagnosis of malignant histiocytic tumors and differential diagnosis are discussed.

Pulmonary neuroendocrine cells in pediatric lung disease: alterations in airway structure in infants with bronchopulmonary dysplasia

Despite four decades of investigation, the function of pulmonary neuroendocrine cells (NEC) remains unclear. Since NEC secretory products may influence airway growth or differentiation or alter airway smooth muscle tone, increased numbers of NEC seen in bronchopulmonary dysplasia (BPD) may be partially responsible for the genesis of the structural and pathophysiological alterations seen in this disease state. Changes in airway structure were studied in six infants dying with BPD and six conceptional age-matched control infants dying of noncardiopulmonary disease. Changes in bombesin-, calcitonin-, and serotonin-immunoreactive NEC were quantified in lung specimens from three infants who died at 2 months of age with severe BPD and three conceptional age-matched controls. There were no differences in either bronchiolar or bronchial airway epithelial areas, but significant increases in bronchiolar (1.8-fold) (P < 0.001) and especially bronchial smooth muscle (2.5-fold) (P < 0.001) were documented in infants with BPD. Few bombesin-, calcitonin-, and serotonin-immunoreactive cells were identified in cartilaginous airways; however, there was a clear increase in the total number of bronchiolar immunoreactive cells in infants with severe BPD (28.5 +/- 11.2 cells/mm airway epithelium) compared to control infants (4.5 +/- 4.9) (P < 0.05). Our results confirm that airway wall composition does change in BPD, but there is either no or an inverse correlation between NEC number and airway epithelial and smooth muscle areas and cell numbers. The role of NEC secretory products in airway smooth muscle growth and function requires further investigation.

Bannayan-Riley-Ruvalcaba syndrome

Here we report on 12 affected members of a family with Bannayan-Riley-Ruvalcaba syndrome. We present clinical evidence of overlap between Bannayan-Zonana syndrome. Riley-Smith syndrome, and Ruvalcaba-Myhre syndrome in this autosomal dominantly inherited condition. We expand the phenotypic spectrum to include Hashimoto thyroiditis, which occurred in 7 of our cases. Finally, we discuss the relationship between the syndrome and juvenile polyposis of infancy.

Mizoribine pharmacokinetics and pharmacodynamics in a canine renal allograft model of local immunosuppression

We utilized a canine renal transplant model to estimate the first-pass extraction of mizoribine (MZB) during renal artery infusion and to compare the efficacy and toxicity of continuous intraarterial (i.a.) versus intravenous (i.v.) MZB delivery, with and without a background of oral cyclosporine. Five autotransplanted mongrel dogs with programmable, implantable pump/catheter systems were given MZB by both i.v. bolus (5 mg/kg) and i.a. infusion (5.0 mg/kg/day). Mean +/- SD elimination half-life was 3.02 +/- 0.81 hr, and the transplanted kidney removed as much as 47-59% (mean 56%) of locally infused MZB. With increasing local and systemic MZB delivery in a single autografted dog undergoing both i.a. and i.v. pump/catheter placement, renal extraction decreased from at least 47% (5.0 mg/kg/day) to 33% (7.5 mg/kg/day), finally to 18% (10.0 mg/kg/day). A dose of 3.0 mg/kg/day MZB did not significantly prolong survival of renal allograft recipients over that of untreated controls (median survival time [MST] = 8 days) when administered either locally (MST = 9 days) or systemically (MST = 12 days). All dogs receiving 4.0 mg/kg/day MZB i.a. died from rejection, and a survival advantage was still not realized (MST = 7 days). In contrast, 4.0 mg/kg/day i.v. prolonged survival over controls (MST = 14 days; P = 0.03) but not when directly compared with the i.a. group (P = 0.30), and produced death from severe debility in five of seven animals with significantly higher mean systemic MZB levels (P = 0.02). Four of six dogs receiving 5.0 mg/kg/day MZB i.a. (MST = 14 days) and two of four dogs receiving 5.0 mg/kg/day i.v. (MST = 14 days) died from severe debility, though survival in both groups was prolonged over control values (P = 0.01 and P = 0.05, respectively). Coadministration of a subtherapeutic dose of oral CsA (5 mg/kg/day) significantly prolonged the overall survival of dogs receiving MZB 4.0 mg/kg/day i.a. (MST = 23; P = 0.01) but not i.v. (MST = 11; P = 1.00), so that a significant difference in overall survival between the combined MZB i.a. + CSA and MZB i.v. + CSA groups was now realized in favor of the former (P = 0.04). We conclude that at local doses required to achieve immunosuppression, the transplanted kidney was not able to extract enough MZB to prevent death from systemic toxicity, presumably as a result of saturation of renal elimination mechanisms, so that an overall survival benefit was not realized.(ABSTRACT TRUNCATED AT 400 WORDS)

Using Good Samaritan Acts to provide access to health care for the poor: a modest proposal

Some states are providing immunity to those willing to voluntarily provide health care for the poor. The proposal is a modest and questionable step toward solving the health care access dilemma.

Pharmacodynamics of local heparin infusion in a canine renal allograft model

Inasmuch as heparin has demonstrated immunosuppressive activity in vivo and in vitro, we utilized a canine renal transplant model to estimate the first-pass extraction of heparin during renal artery infusion and to examine the effect of regional heparin delivery on the histologic features of rejection and allograft survival. Four autotransplanted mongrel dogs with programmable, implantable pump/catheter systems received a continuous intrarenal heparin infusion which was increased daily in stepwise fashion. Activated coagulation time (ACT) rose linearly with local heparin dose, indicating that heparin clearance remained constant over the dosage range studied. Comparison of these ACT values with those measured during same-dose i.v. infusion and those predicted from i.v. bolus studies revealed that there was little or no first-pass renal extraction of heparin by the transplanted kidney. In nine allografted dogs, the heparin infusion rate was adjusted according to daily ACT to maximize local heparin delivery but still maintain the ACT close to 125% of base line. There was no difference in overall survival between the heparin-treated dogs and a group of 14 untreated controls, and vascular rejection was significantly more intense in the heparin-treated animals. We conclude that intrarenal dosing of heparin to the point of producing systemic anticoagulation is limited by failure of the transplanted kidney to eliminate drug and does not prolong canine renal allograft survival.

De novo hemolytic uremic syndrome following renal transplantation

We report a case of complete recovery of renal function in a patient with de novo hemolytic uremic syndrome (HUS) following renal transplantation. This 3-year-old girl had none of the factors known to contribute to the development of HUS in transplant recipients. This case illustrates the usefulness of renal biopsy in the accurate diagnosis and management of dysfunction in the allograft following renal transplantation.

The pharmacokinetic advantage of local 6-mercaptopurine infusion in a canine renal transplant model

In light of recent technologic advances, we developed a canine renal allograft model utilizing implantable, programmable infusion pumps and biocompatible catheters to reexplore the concept of local immunosuppression. Thirteen mongrel dogs underwent bilateral nephrectomy and autotransplantation of 1 kidney via end-to-end renal-iliac artery and end-to-side renal-iliac vein anastomoses. The proximal end of an infusion catheter directed into the iliac artery was tunneled to a subcutaneously placed programmable pump. A second, sampling catheter was placed with its tip in the iliac vein just proximal to the venous anastomosis. During a period of i.a. infusion of heparinized saline ranging from 19 to 63 days, serum creatinine remained normal in all but 1 animal, which developed pyelonephritis and catheter-tip perforation of the iliac artery. No cases of arterial thrombosis or catheter migration were observed at necropsy. In 7 additional autotransplanted dogs, simultaneous iliac vein and systemic (jugular vein) concentrations of 6-mercaptopurine (6-MP), the major immunosuppressive metabolite of azathioprine, were determined during a continuous 24-hr i.a. infusion (10 mg/kg/24 hr). Following termination of the infusion, 10 mg/kg 6-MP was administered to the same 7 dogs as an i.v. bolus, and systemic drug concentrations were determined over a 4-hr period. Mean +/- SE total-body clearance and elimination half-life were 887 +/- 159 ml/min and 1.4 +/- 0.2 hr, respectively, in the i.v. bolus study, indicating that 6-MP is rapidly cleared from the systemic circulation. Unexpectedly, the kidney removed as much as 60-95% of locally infused 6-MP, reducing the amount of active drug entering the systemic circulation to 5-40% of that which would be present during an i.v. infusion of the same dose. According to the principles governing the advantages of i.a. infusions, these data demonstrate that 6-MP can be infused intrarenally to produce both a 4-fold increase in drug concentration within the kidney and an 80% decrease in systemic drug delivery when compared to same-dose i.v. administration. The overall result is the presence of a 30-fold gradient between local and systemic drug concentrations during intrarenal 6-MP infusion. We conclude that i.a. infusion of an immunosuppressive agent is technically feasible with preservation of renal function, and that 6-MP can be delivered locally in a canine model with great pharmacokinetic and potential therapeutic advantage.

Local immunosuppression with reduced systemic toxicity in a canine renal allograft model

We compared the efficacy of continuous intraarterial versus intravenous 6-mercaptopurine (6-MP) infusion in a mongrel canine renal allograft model with regard to overall survival, incidence of systemic and renal toxicity, and systemic drug exposure. Arterial anastomoses were done end-to-end, and infusion catheters were placed in the iliac artery or vena cava and connected to a subcutaneously placed programmable pump. A dose of 0.5 mg/kg/day 6-MP did not prolong survival over heparin-treated or untreated controls (MST = 7 days for both groups) when administered either locally or systemically. However, 0.75 mg/kg/day 6-MP i.a. (MST = 20 days) significantly prolonged survival over both untreated (P = 0.007) and heparin-treated controls (P = 0.02), with all dogs eventually dying of rejection. In contrast, 0.75 mg/kg/day i.v. (MST = 7 days) failed to prolong survival over controls (P greater than 0.1) and produced death from systemic toxicity in 3 of 7 animals. Six of 7 dogs receiving 2.0 mg/kg/day 6-MP i.a. (MST = 12 days) developed azotemia secondary to drug-induced nephrotoxicity. Identical renal histologic changes occurred in the same time frame in autotransplants treated similarly. Of 7 animals receiving 2.0 mg/kg/day i.v. (MST = 12 days), 5 died from early, severe systemic drug toxicity and 2 from early rejection. During 6-MP infusion at 0.5 mg/kg/day, systemic exposure was significantly less in the locally treated than in the systemically treated dogs when Cr concentrations were normal or moderately elevated (P less than 0.0005 and P = 0.01, respectively) but not when renal function became severely impaired (P = 0.34). In contrast to i.v. infusion, i.a. 6-MP delivery dissociated immunosuppressive efficacy from systemic toxicity, supporting previous work demonstrating high first-pass renal elimination of 6-MP. We conclude that tightly controlled local delivery of an immunosuppressive agent can effectively prolong graft survival with reduced systemic toxicity in a large animal model employing a pump/catheter system applicable to man.

Testicular germ cell loss in children with renal failure

Delayed puberty, hypergonadotropism, impaired spermatogenesis, decreased libido and infertility have been reported in males with chronic renal failure (CRF). The number of spermatogonia per seminiferous tubule was quantitated in 22 children with renal failure (RF) in this study using anti-neuron-specific enolase to selectively label these cells. Results were compared to those of puberty and age-matched controls and were subjected to statistical analysis. This study showed that: 1) Children and adolescents with RF have a significantly decreased number of spermatogonia per seminiferous tubule, compared to puberty and age-matched controls; 2) Germinal cell counts in infants with RF under 3 months of age compared to control infants do not reach statistical significance but are borderline; 3) Children with RF over 3 months of age have statistically fewer germinal cells than age-matched controls, a difference which appears to increase with age; 4) Not all children with RF have decreased numbers of spermatogonia while some have an absence of these cells; and 5) The number of spermatogonia per tubule is correlated with increasing age but is not correlated with the duration of RF.

An implantable pump for intrarenal infusion of immunosuppressants in a canine autotransplant model

We developed a canine renal allograft model utilizing implantable infusion pumps and biocompatible catheters to investigate the pharmacokinetics of local immunosuppressive drug administration. Seven mongrel dogs underwent bilateral nephrectomy and autotransplantation of one kidney to the iliac vessels. The proximal end of an infusion catheter directed into the iliac artery was tunneled to a subcutaneously placed programmable pump. A second, sampling catheter was placed with its tip in the iliac vein. Simultaneous regional (iliac vein) and systemic (jugular vein) venous concentrations of 6-mercaptopurine (6-MP), the immunosuppressive metabolite of azathioprine, were determined during a continuous 24-h intraarterial infusion (10 mg/kg/24 hr). The gradient between regional and systemic 6-MP concentrations was maximal initially when the pump was turned on, continuously decreased until steady state was reached, and disappeared immediately after the pump was turned off. The mean ratio of steady-state iliac vein to systemic 6-MP concentrations was 5.0 +/- 1.4, demonstrating a pharmacokinetic advantage of continuous intraarterial 6-MP infusion to the autotransplanted kidney. The novel canine renal allograft model described herein overcomes the technical limitations of earlier models and represents a foundational step in the design of intrarenal infusion patterns of immunosuppressive agents which we expect to prolong survival of the allotransplanted kidney with minimal systemic drug exposure and side effects.

Correlation of clinical and pathologic findings in early onset neonatal group B streptococcal infection with disease severity and prediction of outcome

This study analyzed the clinical characteristics of 69 neonates who were admitted to the University of Minnesota Hospital between January, 1972, and June, 1984, with early onset Group B streptococcal infection (EOGBS) and determined those features associated with fatal infection. The incidence of EOGBS was 1.6 cases/1000 live births among 7960 inborn infants; the mortality rate for inborn and outborn infants was 28%. Multivariate analysis identified five features adequately predicting fatal outcome: birth weight less than 2500 g, absolute neutrophil count less than 1500 cells/mm3, hypotension, apnea and a pleural effusion on the initial chest radiographs. With these five variables and an initial blood pH less than 7.25, a clinical score was constructed that correctly predicted outcome in 93% of patients in this study (87% sensitivity, 95% specificity). Autopsy findings in 16 of 19 infants with fatal EOGBS suggested that surfactant deficiency respiratory distress syndrome was common in preterm infants with EOGBS and contributed to their higher mortality compared with term infants.

Wilms tumor and the VATER association

We describe an infant with the VATER association in whom a Wilms tumor was noted when she was 5 months old. The lower pole tumor arose near the pelvis and grew into an adjacent calix producing a cystic and solid mass with numerous papillary projections resembling sarcoma botryoides. Histopathologically, the tumor was a classical Wilms tumor but it was unusual in that the papillary projections of the tumor were covered by intestinal-like epithelium, which was interpreted as metaplastic urothelium. The margins were free of tumor and the patient is being treated according to the National Wilms Tumor Study Protocol for stage I lesions. She is currently without evidence of recurrence.

Congenital adrenal hypoplasia and selective absence of pituitary luteinizing hormone: a new autosomal recessive syndrome

Congenital hypoplasia of the adrenal glands (CHA) is a rare condition, particularly in the absence of a central nervous system (CNS) anomaly. Two major types of CHA have been described in the setting of an apparently normal CNS and pituitary: a cytomegalic type usually with X-linked recessive inheritance and a miniature adult type that, when hereditary, is an autosomal recessive trait. Glycerol kinase deficiency (GKD) is an X-linked recessive trait, and it may be associated with CHA and adrenal insufficiency, presumably because of deletion of adjacent X-linked loci. We report on three sibling infants, one male and two females, with normal CNS and lethal CHA of the miniature adult type, selective absence of pituitary LH; two of the infants also had glycerol kinase (GK) activity that was decreased but not in the GKD range. Restriction fragment length polymorphism (RFLP) analysis of X chromosome markers located at Xp21-p22 was carried out on the maternal grandfather, both parents, two of three affected infants, and a living normal brother. The results excluded the X-linked type of this disorder associated with GKD in this family. Autosomal recessive inheritance is most likely.

De novo focal glomerulosclerosis after kidney transplantation

A transplanted kidney in a patient developed focal and segmental glomerulosclerosis, associated with severe systemic hypertension, proteinuria, progressive azotemia, and allograft hypertrophy. A pediatric kidney with two main arteries was used, and occlusion of the artery supplying the upper pole resulted in infarction of this portion of the allograft. Because other known factors predisposing to focal sclerosis were absent, it is postulated that renal hemodynamic changes associated with reduction in functioning renal mass, attended by striking stimuli for renal hypertrophy, resulted in progressive damage. The implications of these concepts are discussed in relation to the progression of renal diseases.

Thyrocalcitonin-containing cells in the Di George anomaly

The Di George syndrome is an anomaly characterized by the complete or partial absence of derivatives of the third and fourth pharyngeal pouches often associated with defective development of the third, fourth, and sixth aortic arches leading to absence or hypoplasia of the thymus and parathyroid glands and to cardiovascular anomalies. The fifth pharyngeal pouch, often considered a part of the fourth pouch, gives rise to the ultimobranchial body (UB), which becomes incorporated into the thyroid gland and is thought to be the source of thyroid C cells. Robinson suggested that complete or partial absence of the UB should be considered a part of the Di George anomaly. To substantiate this theory, the thyroid glands of 11 patients with the Di George syndrome and 11 age-matched control infants were examined immunohistochemically using the immunoperoxidase technique for presence or absence of thyrocalcitonin (TC)-containing cells. Only three of 11 patients with the Di George syndrome had TC-containing cells in their thyroid glands (27 per cent), and nine of 11 control infants had these cells (82 per cent). It is concluded that thyroid C cell deficiency is present in most patients with Di George anomaly, suggesting a relationship between these cells and development of derivatives of the third through fifth visceral pouches. Furthermore, there is a spectrum of deficiency of thyroid C cells in these individuals comparable with the spectrum of partial to complete absence of third and fourth pharyngeal pouch derivatives regarding thymus and parathyroid glands. Immunostaining for TC of the lungs of all infants with the Di George syndrome and control infants revealed similar numbers of thyrocalcitonin-containing cells in both groups. Asynchronous development of thyroid and lung thyrocalcitonin-containing cells in those with the Di George syndrome favors the theory that the latter develop independently of derivatives of the third through fifth visceral pouches. This study further supports a neural crest origin of the Di George anomaly and strengthens the concept that the Di George anomaly is a neurocristopathy.

Cellular antigens in nephroblastoma: identification with monoclonal antibodies which recognize hemopoietic cells

The correlation between expression of differentiation antigens and morphogenesis was examined in 11 human nephroblastomas using monoclonal antibodies which recognize both hemopoietic and renal cells. Analysis of frozen tissue sections by indirect immunofluorescence revealed that blastema cells and some tubules were recognized by BA-1 and OKB2, which identify unstimulated B cells and granulocytes. Stroma, some tubules, and focal blastema were recognized by BA-2, which identifies a 24-kDa antigen on leukemic cells and platelets. Mature epithelium in glomerular bodies was identified by C3bR and J5, which recognize CR1 and the common acute lymphoblastic leukemia antigen, respectively. Tissue sections from a clear cell sarcoma and a mesoblastic nephroma were notably reactive only with BA-2. These observations demonstrate that the relationship between antigen expression and morphology in nephroblastomas is similar to that observed in fetal kidney and suggest that expression of these cell surface antigens may have a role in morphogenesis.

Direct hyperbilirubinemia and hepatic fibrosis: a new presentation of Jeune syndrome (asphyxiating thoracic dystrophy)

Jeune syndrome (asphyxiating thoracic dystrophy) is an autosomal recessive skeletal dysplasia with multisystem involvement. The disorder is usually considered lethal, with death resulting from respiratory insufficiency during infancy, or from renal failure during childhood. Hepatic dysfunction, diagnosed on the basis of direct hyperbilirubinemia and hepatic fibrosis, led to early diagnosis of Jeune syndrome in a newborn infant. Review of the literature indicates that the specific pathologic lesion (biliary dysgenesis with portal fibrosis and bile duct proliferation) has been observed as an incidental finding at autopsy, but that clinically significant liver dysfunction has not been appreciated as an important manifestation in this disorder. The characteristic histopathologic abnormality has been present in every patient studied, and may advance during infancy; in contrast, clinical liver dysfunction resolves over the first few months of life. Whereas many patients with Jeune syndrome die early, several have survived into adolescence, suggesting that aggressive treatment is appropriate, especially for those with minimal respiratory and renal involvement. Longitudinal evaluation of liver function and pathology in these survivors is needed to define the long-term prognosis.

Systemic amyloidosis complicating cystic fibrosis. A retrospective pathologic study

A retrospective autopsy study during 1957 to 1983 of patients with clinically documented cystic fibrosis (CF) who were at least 15 years old at the time of death (33 patients) revealed that 11 (33%) had amyloid deposits in multiple organs. The spleen, liver, and kidneys were the principally affected organs, with microscopic deposits mainly restricted to blood vessels. Only one patient had overt clinical manifestations of organ dysfunction secondary to the presence of amyloid. No differences were noted between the groups with (11 patients) and without (22 patients) amyloidosis with respect to age at diagnosis of CF; number, severity, and types of infections; and longevity. Our data demonstrate that amyloidosis is more common in patients with CF than previously reported, and this purported increase parallels the longer life span of these patients. Those patients who are older than 15 years of age constitute the particular group at risk, and they should be evaluated for amyloidosis if unusual clinical findings emerge to suggest it. Clinically evident amyloidosis is uncommon, however, in patients with CF and amyloid deposits at this time. It is likely that clinically relevant amyloidosis will become more of a complicating factor in the future as the life span of these patients continues to increase.

de la Chapelle dysplasia

Since the description by de la Chapelle and colleagues of two sibs with a unique skeletal dysplasia, two additional cases have occurred, one in the original Finnish family and one sporadic patient born to unrelated parents of Belgian descent. The original Finnish family has later had a fourth child, a normal daughter who was found to be unaffected upon radiographic examination in the 19th week of gestation. These additional findings are compatible with recessive inheritance. Physical features common to these four patients include cleft palate, small thorax, moderately severe micromelia with small hands, and equinovarus deformity. In each case, the ulnae and fibulae were reduced to an almost triangular osseous remnant. Other long bones were short and bowed. Neonatal death occurred in all cases and may be attributed to a consistent triad of respiratory tract malformations: laryngeal stenosis, tracheobronchomalacia, and pulmonary hypoplasia. Clinical and radiographic features are sufficiently unique to distinguish de la Chapelle dysplasia from other disorders in the spectrum of neonatal lethal osteochondrodysplasias. Lacunar halos were identified as a distinctive histopathologic feature also observed in achondrogenesis but not in several other skeletal dysplasias.

Clinical and laboratory observations in a child with hepatic phosphorylase kinase deficiency

A 3-year-old child with glycogenosis due to hepatic phosphorylase kinase deficiency is described. His clinical presentation was unusually severe. Biochemical studies revealed a lack of hypoglycemia, the presence of marked ketosis and hyperlipidemia, and a normal glycemic response to glucagon and to loading with galactose, fructose, and alanine. The ketosis was reversed by glucagon administration. Changes in plasma concentrations of lactate, pyruvate, beta-OH butyrate, and alanine in response to glucagon, galactose, fructose, and alanine administration are reported. The child responded poorly to a high protein diet. His condition improved markedly with a high carbohydrate diet. The significance of the findings is discussed.

Secondary (AA) amyloidosis in cystic fibrosis. A report of three cases

The authors report the pathologic features of three cases of amyloidosis associated with cystic fibrosis. Renal biopsy led to the diagnosis (case 1) or suspicion (case 2) of amyloidosis in patients who were 23 and 21 years old, respectively. The third patient died at age 22 years, and amyloidosis was not discovered until autopsy. Immunohistochemical staining and potassium-permanganate pretreatment of histologic sections in all three cases provided evidence that the amyloid seen in these patients is of the secondary (AA) type. Congo red staining in each case and electron microscopy in case 1 confirmed the initial diagnosis of amyloidosis. A markedly elevated serum amyloid A protein (160 micrograms/mL; normal less than 1 microgram/mL) in case 1 indicated the presence of large quantities of the precursor protein from which the AA fibrils of secondary amyloid are derived. The kidneys, spleen, and liver contained amyloid deposits in autopsy material from all three cases. Involvement of other organs by amyloid was variable. Review of autopsy material in Boston from 23 additional cystic fibrosis patients with long-term survival did not reveal any evidence of amyloidosis. It appears that secondary amyloidosis is emerging as a significant, although rare, complication of cystic fibrosis as greater numbers of these patients survive into adulthood.

Pulmonary emphysema in a neonate with Marfan syndrome

A premature infant with arachnodactyly and congenital cyanotic heart disease had severe pulmonary emphysema, a little-known manifestation of Marfan syndrome. The possible etiologies of emphysema in this syndrome are discussed.

The accelerated phase of Chediak-Higashi syndrome. An expression of the virus-associated hemophagocytic syndrome?

The clinical and pathologic findings of four patients with Chediak-Higashi syndrome in the accelerated phase were studied in order to clarify the nature of this enigmatic process. Fever, lymphadenopathy, hepatosplenomegaly, and cytopenias were present in every patient. All cases demonstrated extensive parenchymal infiltrates in many organs composed of benign-appearing histiocytes manifesting hemophagocytosis accompanied by lymphocytes and plasma cells. Studies in one patient suggested a viral etiology with the findings of a low blood lymphocyte OKT4 to OKT8 ratio, acquired loss of lymphocyte response to mitogens, the presence of Epstein-Barr virus genome in the mononuclear cells of lymph node, blood, and bone marrow, and possible clinical responses to acyclovir. It is concluded that the accelerated phase of Chediak-Higashi syndrome may be the clinicopathologic expression of the virus-associated hemophagocytic syndrome.

The changing spectrum of cystic pulmonary lesions requiring surgical resection in infants

Congenital labor emphysema and cystic adenomatoid malformation have been the most common surgically treatable cystic lesions of the lung. With the successful treatment of newborn respiratory distress syndrome, an increased frequency of an acquired form of cystic disease, interstitial pulmonary emphysema, has been observed. Some degree of interstitial pulmonary emphysema is relatively common, and during the years 1980 to 1983 this disease was diagnosed in 372 infants. Seven of these infants, all premature, underwent resection of relatively localized areas of persistent cystic interstitial pulmonary emphysema. Lobectomy or wedge resection was performed in five patients because of their inability to be weaned from the ventilator. A sixth patient with this disease underwent lobectomy for recurrent pneumothoraces. A seventh patient underwent lobectomy because the cystic interstitial pulmonary emphysema produced atelectasis and recurrent infections. All seven patients were extubated by the fourth postoperative day, have been discharged, and are showing respiratory improvement. Within the same period, four infants had congenital lobar emphysema and two had congenital cystic adenomatoid malformation. They were gestational age 36 weeks or older and, although respiratory distress was present to some degree in all six, only one was ventilator dependent at operation. All underwent lobectomy and one infant had a left upper lobe resection and right middle lobectomy on separate occasions for bilateral congenital cystic adenomatoid malformation. All patients with congenital labor emphysema and congenital cystic adenomatoid malformation have been discharged and are doing well. Our results suggest the following conclusions: Persistent interstitial pulmonary emphysema is now the most common indication for pulmonary resection in the newborn period. The anatomic distribution of resected interstitial pulmonary emphysema is similar to that of congenital lobar emphysema. Although only a small fraction (less than 2%) of patients with interstitial pulmonary emphysema require operation, the development of relatively large discrete cystic areas that (1) significantly decrease effective lung volume and produce respirator dependence, (2) produce atelectasis and recurrent infections, or (3) lead to pneumothoraces may make pulmonary resection beneficial. Finally, despite the presence of generalized lung disease in patients with interstitial pulmonary emphysema, these patients can be expected to improve significantly after resection, and the long-term outcome is generally good.

Morphologic changes induced by dilation of the pulmonary valve anulus with overlarge balloons in normal newborn lambs

The optimal method for balloon dilation valvuloplasty of congenital pulmonary valve stenosis has not been established. The cardiac damage produced by using a balloon the same size as the pulmonary anulus has not been described. The use of balloons that are larger than the anulus or of a dynamic dilation technique may enhance gradient reduction, but their added risks are not known. The pulmonary valve anuli of 14 normal newborn lambs were dilated with angioplasty balloons 20% smaller to 90% larger than the anulus; in 3 dilations, a dynamic technique was used, consisting of withdrawal of the fully inflated balloon from the anulus into the body of the right ventricle. Twelve lambs were killed immediately after the procedure and 2 were killed later, and detailed gross anatomic and microscopic observations of the heart were made. These observations support the following conclusions: (1) Dilation of the pulmonary valve anulus with overlarge balloons is "clinically" well tolerated in normal newborn lambs. (2) The major damage to the heart from any balloon is not the pulmonary anulus, but to the right ventricular outflow tract and free wall, with mural hemorrhages of varying size. (3) Trauma is minor if the balloon is 30% larger than the anulus, but is considerable when the balloon is 50% larger; (4) Trauma is worst subjacent to the proximal end of the balloon, so that longer balloons may cause greater damage; and (5) Resolution of acute right ventricular hemorrhage occurs with small, patchy areas of fibrosis.

Sarcomatoid transitional cell carcinomas of the renal pelvis. An ultrastructural and immunohistochemical study

Transitional cell carcinomas of the urinary tract may occasionally assume a partial or complete spindle cell pattern of growth, leading to the erroneous classification of some true carcinomas as sarcomas. We have recently observed two such tumors of the renal pelvis. In these cases, ultrastructural study showed that the spindle cells retained features of epithelial differentiation; this conclusion was further supported by positive results of several immunohistochemical stains, using biotinylated peanut agglutinin and soybean agglutinin, and a rabbit antiserum directed against keratin proteins. In addition, both tumors manifested immunoreactivity for blood-group antigens, using primary murine monoclonal antibodies. The results of these studies suggest that immunocytochemistry is a helpful diagnostic adjunct in the proper classification of sarcomatoid urothelial neoplasms.