Treatment of advanced heart failure in adults with congenital heart disease: a narrative review and clinical cases

BACKGROUND AND OBJECTIVE

The number of adults with congenital heart disease (ACHD) is increasing worldwide. Almost all congenital cardiac lesions can be successfully treated due to the progress in neonatal surgery and pediatric cardiology with a high likelihood of surviving until adulthood. However, ACHD frequently develop sequelae related to the initial cardiac anomaly. Heart failure (HF) is one of the most common complications associated with a high morbidity and mortality.

METHODS

The authors did search the PubMed database regarding relevant content covering publications up to March 2022. Relevant manuscripts were classified according to the impact factor of the journal, being a guideline manuscript, a position paper by a society or a comprehensive review of the current literature.

KEY CONTENT AND FINDINGS

Optimal HF treatment remains an unmet need in ACHD. In particular, advanced HF therapy with cardiac resynchronization therapy, ventricular assist devices or organ transplantation is still very different and more specific in ACHD compared to non-ACHD. This review aims to compile international views and evidence from the literatures on the treatment of advanced HF in ACHD. Current challenges, but also the success of different treatment strategies in ACHD are illustrated by clinical cases.

CONCLUSIONS

The main finding of the review is that data is still scarce regarding ACHD with advanced HF and international efforts to collect data regarding these patients needed to improve the current standard of care.

Symptomology following mRNA vaccination against SARS-CoV-2

Despite demonstrated efficacy of vaccines against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of coronavirus disease-2019 (COVID-19), widespread hesitancy to vaccination persists. Improved knowledge regarding frequency, severity, and duration of vaccine-associated symptoms may help reduce hesitancy. In this prospective observational study, we studied 1032 healthcare workers who received both doses of the Pfizer-BioNTech SARS-CoV-2 mRNA vaccine and completed post-vaccine symptom surveys both after dose 1 and after dose 2. We defined appreciable post-vaccine symptoms as those of at least moderate severity and lasting at least 2 days. We found that symptoms were more frequent following the second vaccine dose than the first (74% vs. 60%, P < 0.001), with >80% of all symptoms resolving within 2 days. The most common symptom was injection site pain, followed by fatigue and malaise. Overall, 20% of participants experienced appreciable symptoms after dose 1 and 30% after dose 2. In multivariable analyses, female sex was associated with greater odds of appreciable symptoms after both dose 1 (OR, 95% CI 1.73, 1.19-2.51) and dose 2 (1.76, 1.28-2.42). Prior COVID-19 was also associated with appreciable symptoms following dose 1, while younger age and history of hypertension were associated with appreciable symptoms after dose 2. We conclude that most post-vaccine symptoms are reportedly mild and last <2 days. Appreciable post-vaccine symptoms are associated with female sex, prior COVID-19, younger age, and hypertension. This information can aid clinicians in advising patients on the safety and expected symptomatology associated with vaccination.

High thrombus burden despite thrombolytic therapy in ST-elevation myocardial infarction in a patient with COVID-19

Consideration of thrombolysis as first-line reperfusion therapy in patients with COVID-19 and STEMI is recommended by ACC/SCAI guidelines. We describe a patient with COVID-19, who presented with ST-elevation myocardial infarction and was treated with thrombolysis and anticoagulation. He was later found to have a significant persistent thrombus burden requiring thrombectomy and stent placement. Invasive hemodynamics on multiple high-dose pressers revealed a high cardiac output state with low systemic vascular resistance, consistent with distributive rather than cardiogenic shock. Our case illustrates that thrombolytic therapy alone may not be adequate in patients with STEMI and COVID-19, as well as the importance of early invasive hemodynamics in management of shock in patient with STEMI and COVID-19 infection.

The development of retinal ganglion cells in a tetraploid strain of Xenopus laevis: a morphological study utilizing intracellular dye injection

The morphological development of retinal ganglion cells was examined in a tetraploid strain of Xenopus frogs. The enlarged cells of the tetraploid strain facilitate the application of intracellular techniques. Using an in vitro retinal preparation and Nomarski optics, intracellular recording and dye injection were carried out under visual control on ganglion cells in central retina from 2 days of development (stage 24) to metamorphosis (stage 64). We identified three phases in the morphological differentiation of ganglion cells. During the first phase (stages 24-30), all cells were neuroepitheliallike in form and possessed robust resting potentials in the range of -35 to -60 mV, and dye-coupling was occasionally observed between neighboring cells. During the second phase of ganglion cell development (stages 31-45) the neurons had begun to elaborate axons and dendrites. These cells possessing neurites had resting potentials between -15 and -30 mV, and no dye-coupling was observed between neighbors. During the third and final phase of maturation, from stage 46 onward, three distinct morphological types of ganglion cells could be identified. Type I cells had the smallest somata and the smallest-diameter dendritic arborizations. The profusely branched dendrites of these cells ramify extensively throughout the inner plexiform layer. Type II cells had large somata, intermediate-diameter dendritic fields, and a highly elaborate dendritic branching pattern. These cells were seen to arborize within two sublamina in the inner plexiform layer. Type III cells had large somata, the largest-diameter dendritic fields, and a dendritic arbor with long primary branches but little higher-order branching. These large dendritic fields were confined to a single sublamina of the inner plexiform layer, abutting the inner nuclear layer. While most phase 3 cells showed radial axon trajectories from the soma to the optic disc, a minority of cells (1-5%) with erratic and nonradial axon trajectories were also observed. Our data provide a morphological description of ganglion cell maturation in the central retina of Xenopus. We show that very early in development (as early as stage 46) three distinct morphological types of retinal ganglion cells are present, which correspond to the three classes of ganglion cells previously described in adult Xenopus (Chung et al., '75).

A quorum sensing-associated virulence gene of Pseudomonas aeruginosa encodes a LysR-like transcription regulator with a unique self-regulatory mechanism

The human opportunistic pathogen Pseudomonas aeruginosa strain PA14 infects both plants and animals. Previously, using plants to screen directly for P. aeruginosa virulence-attenuated mutants, we identified a locus, pho34B12, relevant in mammalian pathogenesis. Here, nonsense point mutations in the two opposing ORFs identified in the pho34B12 locus revealed that one of them, mvfR (multiple virulence factor Regulator), is able to control all of the phenotypes that mutant phoA34B12 displays. Both genetic and biochemical evidence demonstrate that the mvfR gene encodes a LysR-like transcriptional factor that positively regulates the production of elastase, phospholipase, and of the autoinducers, 3oxo-dodecanoyl homoserine lactone (PAI I) and 2-heptyl-3-hydroxy-4-quinolone (PQS), as well as the expression of the phnAB operon, involved in phenazine biosynthesis. We demonstrate that the MvfR protein is membrane-associated and acts as a transcriptional activator until cells reach stationary phase, when a unique negative feedback mechanism is activated to signal the down-regulation of the MvfR protein. This work reveals an unprecedented virulence mechanism of P. aeruginosa and identifies a unique indispensable player in the P. aeruginosa quorum-sensing cascade.

American Burn Association/Shriners Hospitals for Children burn outcomes questionnaire: construction and psychometric properties

To develop a standardized, practical, self-administered questionnaire to monitor pediatric patients with burns and to evaluate the effectiveness of comprehensive pediatric burn management treatments, a group of experts generated a set of items to measure relevant burn outcomes. Children between the ages of 5 and 18 years were assessed in a cross-sectional study. Both parent and adolescent responses were obtained from children 11 to 18 years old. The internal reliability of final scales ranged from 0.82 to 0.93 among parents and from 0.75 to 0.92 among adolescents. Mean differences between parent and adolescent were small; the greatest difference occurred in the appearance subscale. Parental scales showed evidence of validity and potential for sensitivity to change. In an effort to support the construct validity of the new scales, they were compared with the Child Health Questionnaire and related to each other in clinically sensible ways. These burn outcomes scales reliably and validly assess function in patients with burns, and the scales have been developed in such a way that they are likely to be sensitive to change over time.

Early burn center transfer shortens the length of hospitalization and reduces complications in children with serious burn injuries

Prompt transfer of the child with acute burns can be difficult from distant or inaccessible locations, and it is believed that the outcomes of children with serious burns whose transfer to a specialized burn care facility is delayed may be compromised. A 4-year experience with 16 consecutive children with serious burns (> or =20% of the body surface area) whose transfer to a burn care facility was delayed for 5 or more days was reviewed to document the difficulties that can follow such delays. These 16 children had an average age of 8.6+/-1.6 years and an average wound size of 57.6%+/-5.8% of the body surface area, and they arrived a mean of 16.3+/-3.4 days after the injury (range, 5 to 44 days). These children had undergone an average of 1 operation, excluding escharotomies, at referring facilities. Only 4 (25%) of the children had no infectious focus at transfer, and at admission resistant bacteria were recovered from 9 (56%) of the children and fungal organisms were found in 10 (63%). Compared with a concurrently managed matched control group of patients admitted to the burn center within 24 hours of injury, the delayed-transfer group had statistically significantly more bacteremia, renal dysfunction, wound sepsis, and central venous catheter days. It was also more expensive to manage these children; the delayed-transfer group required statistically significantly longer to achieve 95% wound closure, and they had greater total lengths of hospital stay and more rehabilitation days. The early transfer of children with serious burns to a specialized burn center may truncate hospitalization and thereby reduce costs.

Percutaneous endoscopic gastrostomy in burn patients

BACKGROUND

Prolonged enteral feedings are required occasionally in seriously burned individuals. We have employed percutaneous endoscopic gastrostomy (PEG) in selected patients who require particularly prolonged access, thus prompting this review.

METHODS

The PEG procedure was performed under general anesthesia in combination with another surgical procedure using a variety of commercially available needle and guidewire kits in 14 patients.

RESULTS

These 14 patients had an average age of 55.2 +/- 6.6 years and a burn involving 38 +/- 8% of the body surface. Eleven of these patients had suffered an inhalation injury. The tubes were placed an average of 57 +/- 10.5 days after injury through unburned and unharvested skin in four patients (28%), healed donor sites in five patients (35%), healed burn in one patient (1%), and grafted burn in four patients (28%). One patient, whose catheter was placed through a grafted fascial excision, developed moderate local wound erosion. Tubes were known to have been left in place as long as 155 days. However, most were removed in rehabilitation hospitals, and we were unable to determine how long most were left in place. We are unaware of any problems with the tubes occurring after discharge from the acute care setting.

CONCLUSIONS

In selected patients, PEG can provide more comfortable access for prolonged enteral feedings than nasogastric tubes and can be placed with minimal morbidity.

A practical method of differential hypothermia to permit use of a low pump oxygenator flow

By cooling the blood just before returning it to the body, marked reduction in the temperature of the heart, brain, liver, and kidney can be produced easily and with great economy in heat transfer, since the great bulk of the animal or patient, consisting of skin, muscle, and bone, is cooled much more slowly. This results in a marked oxygen saving, due to the direct antimetabolic effect of the cooling. Metabolic acidosis can be avoided and so far no irreversible effects of the cooling have been discoverable. Warming is so greatly facilitated by the heat stored in the nonvital areas that it is not necessary to warm the blood returning from the extracorporeal circuit. The use of safe, low, extracorporeal flows offers a number of possible advantages including great simplicity of cannulation and of the pump oxygenator design and operation.

Acellular allodermis in burns surgery: 1-year results of a pilot trial

We grafted 10 sites on 6 children with limited (< 25%) areas of body surface available for donor harvest with an acellular allogenic dermis and a thin autograft. Matched control sites were grafted with autograft alone. Study site autografts (0.0074 +/- 0.0007 in, median 0.006 in, range 0.006 to 0.012 in) were thinner than control site autografts (0.0102 +/- 0.0008 in, median 0.012 in, range 0.006 to 0.013 in), with a P value of .015. Endopoints were initial engraftment (in percent) as judged by a blinded experienced observer and Vancouver scar scores. The 6 children (3 girls and 3 boys) had an average age of 5.2 +/- 0.9 years (range 2.8 to 10 years) and an average burn size of 68.7% +/- 6.7% total body surface area (range 47% to 85% total body surface area). The 10 study and control sites were treated with 10 separate procedures; 9 of the procedures were reconstructive and 1 was performed for the excision of an acute burn. Successful initial epithelialization was noted at 7 days postburn for 83% +/- 3.4% (range 60% to 95%) at the cryopreserved acellular human dermis sites and 83.3% +/- 4.3% (range 60% to 98%) at the control sites (not significant, P = .96). At a mean follow-up interval of 43.7 +/- 3.6 weeks (median 52, range 26 to 52 weeks), the differences between the study and control sites in the total mean (pigmentation, vascularity, pliability, and height) of the patients' Vancouver scar scores were not different.

Development of a pediatric burn pain and anxiety management program

To facilitate effective management of pain and anxiety, and to permit more objective assessment of changes in this management, a pain and anxiety guideline was developed and has been followed uniformly for 3 years. The guideline describes four patient care categories: (1) ventilated acute, (2) nonventilated acute, (3) chronic acute, and (4) reconstructive. A small and consistent formulary was emphasized. A specific guideline for background, procedural, and transition pain and anxiety management was developed for each patient care category. All pain and anxiety medications given to all acutely burned children admitted to the Institute for 12 consecutive months were recorded, and daily pain and anxiety discomfort scores were noted using a 5-level action-based bedside scoring system. Doses of individual pain and anxiety medications were calculated as mg per kg per patient-day in each category, and all doses were found to be within guideline specifications. The efficacy of the guideline was judged by four discomfort scores: (1) background pain, (2) procedural pain, (3) background anxiety, and (4) procedural anxiety, and were adequate in all patient categories. There were no complications related to overmedication experienced during the interval. Our objective was to develop a guideline for pain and anxiety management that: (1) was safe and effective over a broad range of ages and injury acuities seen in the unit, (2) was explicit in its recommendations, (3) had a limited formulary to optimize staff familiarity with agents used, and (4) took advantage of the presence of a bedside nurse to continuously evaluate efficacy and intervene when needed through dose-ranging. Although many drugs are appropriate, our choices were based on institutional familiarity and simplicity. This process of developing a clear and consistent guideline can be duplicated in any unit.

Tunable dye laser neovessel ablation as an adjunct to the management of hypertrophic scarring in burned children: pilot trial to establish safety

Hypertrophic scarring is a major source of morbidity in patients with burns. The physiologic characteristics are poorly understood, but increased neovascularity is typically seen in those wounds destined to become hypertrophic. We theorize that ablation of the developing neovasculature may favorably influence the development of the hypertrophic scar. The goal of this pilot trial was to establish the practicality and safety of tunable dye laser neovessel ablation at 585 nm. Ten sites of evolving hypertrophic scar in nine children were treated with a series of 450 msec 6.75 J/cm2 pulses at 585 nm. Although all children had the expected transient posttreatment purpura, no pain, ulceration, pruritus, or worsening of the lesions was seen. The technique appears safe and is worthy of continuing investigation. Investigations with higher fluences and multiple treatments are in progress.

Numerical isotopomer analysis: estimation of metabolic activity

The use of stable isotopes to analyze intracellular metabolism is a powerful technique because of the wealth of information contained in the distribution of isotopes in key metabolites. We present a new numerical method of using measurements of isotope isomer (isotopomer) distributions to calculate the fluxes through a biochemical reaction network. Nuclear magnetic resonance (NMR) and/or mass spectroscopy can quantify the isotopomers which result from the metabolism of an isotopically enriched substrate. These data can be analyzed via a numerical model of the metabolic network which uses atom-mapping matrices to simplify model construction. The atom-mapping matrices describe the transfer of atoms from reactant to product and the resulting isoopomer balance equations are compact and intuitive. These equations are solved iteratively to determine the unknown intracellular fluxes. Results from the numerical method agreed with an analytical solution developed for the analysis of the tricarboxylic acid cycle in perfused hearts.

Diffuse bile duct tumors: guidelines for management

The majority of patients with bile duct cancer have small focal adenocarcinomas localized to the upper, middle, or lower third of the bile duct. In contrast, a small subgroup of patients have been identified with bile duct tumors that are diffuse, involving multiple segments of the extrahepatic biliary tract. Among 186 patients with documented bile duct cancer treated at the UCLA Medical Center between 1954 and 1988, 13 patients (7%) had diffuse lesions. Patients with diffuse tumors had markedly poorer survival rates than did those with focal lesions. As diffuse tumors are not amenable to resection, surgical management consists primarily of establishing suitable biliary drainage. All patients with bile duct cancer should undergo careful intraoperative evaluation to exclude a diffuse lesion before tumor resection.

Bile duct carcinoma in the elderly. A rationale for surgical management

Recent studies have advocated the nonoperative treatment of elderly patients with bile duct cancer using biliary endoprostheses. In addition to a 30-day mortality rate of 9%, disadvantages with this approach include lack of a definitive diagnosis and the inability to assess resectability. For comparison, we reviewed 42 consecutive cases of bile duct cancer managed surgically at UCLA (from 1954 to 1988) among patients age 70 years or older. Histologic confirmation of bile duct cancer was obtained for 40 surgical patients (95%) in the series. The 30-day mortality rate was 10%. There was a trend to more aggressive surgical management during the study, with a concomitant doubling in survival rates (from 21% among patients treated between 1954 and 1978 to 53% among patients treated between 1979 and 1988 at 1 year after surgery.) We conclude that elderly patients should not be denied surgical evaluation of malignant neoplasms of the bile duct simply on the basis of age.

Role of natural killer cells in resistance to Cryptococcus neoformans infections in mice

Previous studies have suggested a possible role for natural killer (NK) cells in resistance to some fungal infections, including Cryptococcus neoformans infections. The role of NK cells in early clearance of C neoformans from tissues and in long-term survival was studied in mice following intravenous inoculations of the organism. Mice treated with anti-asialo GM1 antiserum to temporarily reduce NK activity demonstrated an increase in colony-forming units (CFU) of C neoformans in the lung 24 hours after an intravenous inoculation of the organism. CFU in liver, spleen, kidney, and brain were not different in anti-asialo GM1 antiserum-treated versus control mice. An NK-specific reagent, anti-NK 1.1 monoclonal antibody, was used to deplete mice of NK cells in vivo for at least 14 days without affecting other natural defenses. The number of C neoformans retained in the lungs 24 hours after inoculation of the organism was significantly greater in NK cell-depleted mice than in controls, although CFU in other organs were unaffected. Following the intravenous inoculation of C neoformans, the survival of anti-NK 1.1-treated mice was not different from control mice. The effect of NK cell activity on resistance to C neoformans was also determined after an intratracheal inoculation of the organism. Mice pretreated with anti-NK 1.1 demonstrated no increases in CFU in the lungs, spleen, or brain as compared with controls. These data indicate that NK cells can play a role in vivo in early resistance against C neoformans if the organism is delivered via the intravenous route. However, NK cells do not play a role in either determining survival after an intravenous inoculation nor in resistance during an infection acquired via the respiratory tract.

Effect of tetraploidy on dendritic branching in neurons and glial cells of the frog, Xenopus laevis

Morphological aspects of four different groups of Golgi impregnated brain cells from a tetraploid strain of Xenopus laevis frogs were compared to analogous cells in comparably sized diploid frogs. The cells examined included neurons from the telencephalon, caudal hypothalamus, and optic tectum, and radial glial cells from the optic tectum. The brains of tetraploid frogs appeared grossly normal and were the same size and contained similar cell types as diploid brains. As observed in previous studies on polyploid amphibia, somal diameters increased significantly in tetraploid cells for each of the four groups of cells examined. Also, the total length of the dendritic arbors in tetraploid brain cells increased significantly by factors ranging from 1.4 to 2.4 times the total length of the analogous processes in diploid cells. Tetraploid neurons in the telencephalon and hypothalamus increased their arbor lengths predominantly by increasing the number of dendritic branches, while maintaining the average distance between branch points in the dendritic segments. In contrast, the tetraploid large pear-shaped neurons in the optic tectum had significantly longer terminal dendritic segments than the analogous diploid neurons, although these tetraploid neurons maintained their average number of dendritic segments per cell. Tetraploid tectal radial glial cells appeared to increase both their number of branches and the lengths of their terminal segments. Thus, the mode by which tetraploid brain cells achieved longer dendritic arbors varied from cell type to cell type. These results suggest a hypothetical basis for possible effects of genomic size on vertebrate brain structure and evolution at the cellular level.

Unresponsive, a behavioral mutant in Xenopus laevis: electrophysiological studies of the neuromuscular system

Normal Xenopus laevis embryos begin movements at 1 day after fertilization. Embryos homozygous for the unresponsive mutation fail to move until 4 days after fertilization (just prior to feeding), after which they recover slowly. Electrophysiological studies were undertaken to determine the focus of this mutation. Formamide treatment of normal embryos was used to produce a phenocopy of the unresponsive condition, permitting direct comparisons between mutant and normal embryos. Intracellular recordings from muscle cells were obtained in formamide-treated and untreated preparations with both normal and unresponsive animals. Local electrical stimulation evoked either isolated endplate potentials and action potentials or after-discharges of these events in all preparations. A decrease in illumination also caused a burst of endplate potentials and action potentials. Therefore, the electrophysiology of the neuromuscular junction in unresponsive appears qualitatively normal; the effect of the mutation on the motor system is probably distal to the neuromuscular junction, either at or subsequent to excitation-contraction coupling.

Gene-centromere mapping in Xenopus laevis

Gynogenesis was used to map eight loci to their centromeres in Xenopus laevis. Several loci remote from their centromeres were identified. This information may be useful in distinguishing gynogenetic diploid progeny produced by suppression of second polar bodies from gynogenetic diploid progeny homozygous at all loci produced by suppression of first cleavage of gynogenetic haploids.

Regulation in the neural plate of Xenopus laevis demonstrated by genetic markers

To follow the subsequent history of grafted tissue in experiments designed to study regulation and commitment in the amphibian neural plate, previous workers have relied on graft scars, vital dyes applied externally to cells, or xenoplastic grafts. Each of these methods has been criticized on the grounds that they do not indicate unambiguously the origins of individual cells within the operated host. To overcome these difficulties, homoplastic, genetically marked embryonic grafts were taken from the prospective spinal neuroectoderm of triploid and tetraploid Xenopus laevis frogs and transplanted to presumptive eye and prosencephalic regions of the neural plate of diploid X. laevis embryos. Orthotopic presumptive eye grafts also were done. Marked cells were scored in section either by nucleolar number or computerized nuclear size analysis. Of 28 heterotopically grafted embryos that survived to stage 41, when the retina has differentiated, prospective spinal cord neuroectoderm in eight animals gave rise to cell types unique to the eye. The remaining 20 survivors appeared to be mosaic. These results substantiate claims of regulation in the neural plate and extend these observations to the level of individual cell types, a level of resolution not previously obtained in other studies.

Developmental mutants isolated from wild-caught Xenopus laevis by gynogenesis and inbreeding

Xenopus laevis obtained from indigenous African populations are a rich source of mutants affecting development. Gynogenesis and inbreeding were used to isolate mutants affecting development from wild-caught Xenopus laevis females. Fourteen mutants were recovered from eight females tested. One mutant was recovered from each of two females. This load of 1.875 developmental mutants per female is similar to that found in the axolotl (Ambystoma mexicanum), a urodele amphibian, and is only slightly less than the load of mutants with major developmental effects found in Drosophila and man. These results suggest that the anuran amphibian Xenopus laevis, an ancestrally tetraploid species, has undergone extensive diploidization of developmentally important loci and that gynogenesis and inbreeding of wild-caught animals can provide adequate mutants at diploid loci for developmental genetic studies.

Two healing patterns correlate with different adult neural connectivity patterns in regenerating embryonic Xenopus retina

Nasal and temporal one-third-sized eye fragments, formed by ablation at stage 32-33 of Xenopus laevis embryos, heal and, in about 50% of the cases, survive to make eyes in the postmetamorphic animal which have mappable visuotectal projections. The majority of nasal one-third eyes have duplicate projections whereas the majority of temporal one-third eyes have unduplicated projections. Most nasal one-third eye fragments and a minority of temporal eye fragments heal by the extrusion of cells from the center of the cut edge into the region of the ablation, forming a tongue of cells between the distal cut edges. This healing pattern is correlated with duplicated visuotectal projections. Most temporal one-third fragments and a minority of nasal one-third fragments heal by rounding up; that is, the distal cut edges collapse to meet in the region of the ablation. This healing pattern is correlated with the formation of unduplicated visuotectal projections. During tongue formation, neurons and undifferentiated cells are transferred from the original fragment into the tongue in a disorderly array, but quickly re-form normal retinal order. We propose that the tongue cells retain their original determination to connect to the same tectal positions as the fragment from which they originated, despite their new positions, and that this mosaicism, coupled with cell movement into the tongue, established duplicate visuotectal projections.

Biliary secretion of sulindac and metabolites in man

The biliary secretion of sulindac and metabolites after a single 400 mg oral dose of the drug was studied in 3 elective gallbladder surgical patients following placement of an occludable T-tube in the common bile duct. Bile and systemic plasma were sampled at frequent intervals for up to 36 h postdose. The apparent biliary clearance (Vcl,bile) of the prodrug sulindac is about 25 times greater than that of the pharmacologically active sulfide metabolite. The total biliary flux of drug in normal man with an uninterrupted enterohepatic cycle, calculated from Vcl,bile and historic mean plasma drug AUCinfinity0 values, averages 144 and 12.2 per cent of the dose as sulindac and the sulfide metabolite, respectively. Thus, enterohepatic recycling of the drug in man is principally in the form of the prodrug which not only limits exposure of the intestine to the active moiety but also sustains systemic concentrations of active drug upon reabsorption of the prodrug.

Tolerance maintenance depends on persistence of the tolerizing antigen: evidence from transplantation studies on Xenopus laevis

In order to assess the role of antigen persistence in the tolerant state, tolerance was induced in Xenopus laevis by the embryonic transplantation of whole eyes or tail tissue. Both types of transplants were seen to heal in and persist, with no signs of immunological incompatibility. At metamorphosis, tail resorption occurred and grafted tail tissue was lost. Eye transplants were maintained through metamorphosis in most eye grafted animals. Eye graft recipients which had maintained the transplant were observed to accept challenge skin allografts from donors of the same genotype as the eye donor in all but one case, while recipients which had lost the eye transplant at metamorphosis or had the eye transplant experimentally removed sometimes did not accept the challenge skin graft. Animals tail grafted as embryos did not accept post metamorphic skin grafts from donors of the same genotype as the tail tissue donor, but rejection was not accelerated. It is proposed that tolerance induction is dependent on the presence of appropriately presented antigen at a time when precursor thymocyte cells are migrating to the thymus, prior to their processing into alloreactive cells, and that tolerance maintenance is dependent upon the persistence of the tolerizing antigen.

Allograft rejection in Xenopus laevis following larval thymectomy

Xenopus laevis thymectomized at stages 41 through 49 accept first set allografts, while animals thymectomized at stage 51 or older reject allografts in times similar to intact animals. However, thymectomy at progressively earlier stages results in a greater proportion of animals unable to reject second set grafts. In some animals, the allograft response remains deficient even after multiple challenges. The results indicate that alloreactive cells are thymus dependent, and suggest that the thymus processes precursor thymocytes starting upon its formation at around stage 41. The processed cells, competent to respond to alloantigens, are released to the periphery almost immediately. While an increasing pool of processed T cells accumulates during stages 41-49, the persistent defective allograft response displayed by animals thymectomized during these stages suggests that early thymectomy may leave a population of alloreactive cells qualitatively defective in some subpopulation necessary for normal allograft responses, or that any residual cells processed prior to thymectomy are capable of only limited clonal expansion.

A clinical trial of fibroblast transplantation for the treatment of mucopolysaccharidoses

This paper reports the clinical and biochemical results in six patients with Hurler disease (Mucopolysaccharidosis IH; McKusick 25280), two patients with Hunter disease (Mucopolysaccharidosis II; McKusick 25285) and one patient with Sanfilippo B disease (Mucopolysaccharidosis IIIB; McKusick 25292) who were treated by fibroblast transplantation. Except for one patient who died for a coincidental reason, the patients have been studied for between 2.5 and 4.5 years. The clinical course of the disease was not materially altered. There was no evidence that the patients had developed immune responses against the transplanted fibroblasts. Transplantation did not produce measurable levels of either alpha-L-iduronidase (EC 3.2.1.76) in the leukocytes from patients with Hurler disease or of N-acetyl-alpha-D-glucosaminidase (EC 3.2.1.50) in the plasma of the patients with Sanfilippo B disease. Under the conditions used for the assay, leukocytes from the patients with Hunter disease had detectable levels of residual alpha-L-idurono-2-sulphate sulphatase activity which were increased after the transplants, although these changes were of inconstant size and their time course was not consistently related to the transplantations. Cytogenetic studies in cases where the donor was of the opposite sex detected only cells of the recipient's sex among the fibroblasts grown from biopsies of the transplantation sites. The technique used would have detected a donor to recipient cell ratio of 1:100. We found no consistent long-term trends in the excretion patterns of glycosaminoglycans and oligosaccharides from either a quantitative or qualitative point of view which could be specifically related to the transplantation. The combined administration of immunosuppressive doses of prednisolone and azathioprine was associated with an increased excretion of the lower molecular weight glycosaminoglycans. We conclude that fibroblast transplantation is not therapeutically useful in the diseases studied.

Electroconvulsive therapy and memory dysfunction: is there evidence for prolonged defects?

The authors reviewed 39 papers which concern the long-term effects of electroconvulsive therapy (ECT) on human memory. Although the authors caution that methodological considerations preclude a decisive assessment, the majority of the studies suggest that ECT does not normally produce prolonged memory defects. Some recent studies do document subtle but persistent defects several months after ECT, especially in personal autobiographical material. These defects appear to be more annoying than seriously incapacitating. Variables considered important in an ideal design of studies on ECT and memory are discussed.

Clarification of studies on the origin of thymic lymphocytes

The thesis that lymphocytes originate in situ by the direct transformation of epithelial cells within the thymic primordium in anurous frogs is untenable. On the contrary, in both the leopard frog and the African clawed toad, the lymphocytes that first appear in the embryonic thymus are derived from extrathymic lymphopoietic cells that invaded the developing organ. The exact source of origin of the invading lymphopoietic cells remains problematic.

Neuroanatomy of Spastic, a behavior mutant of the mexican axoloti: Purkinje cell distribution in the adult cerebellum

The spastic mutant, found in the Mexican axolotl, shows swimming coordination and equilibrium deficiencies. Histological analyses of wild-type and spastic mutant cerebella previously characterized in physiological studies revealed changes in Purkinje cell location in the mutant auricle or vestibulo-cerebellum. Purkinje cells are "translocated" ventrally correlated with a similar translocation of vestibular single units described previuosly (Ide, '77). Where wild-type Purkinje cells are distributed from the surface to a depth of 250 micrometers, mutant Purkinje cells are "crowded" between 250 and 350 micrometers. Although mutant granule cells are present, boundaries between granule cell and Purkinje cell zones are less precise in mutants. Cerebellar nucleus cells are translocated medially, failing to organize into the discrete cell group appearing in wild-type. Cerebellar white matter tracts and fibers show changes, both in orientation with respect to the underlying tegmentum, and in fascicular organization. Obvious changes in the gross anatomy of the cerebellum are confirmed in reconstructions which define cell and fiber translocation. Thus, the spastic gene is compatible with differentiation of all cerebellar elements, but appears to alter interactions between cells, or between cells and the external milieu. Although all cell types are present in the mutant cerebellum, they fail to attain their proper positions along all three body axes.

Selective reinnervation in skin rotation grafts in Rana pipiens

Skin rotation grafts were performed in Rana pipiens tadpoles producing misdirected reflexes in adult frogs. The pattern of innervation fields of dorsal and ventral rami of segmental nerves 3, 4, 5 and 6 were investigated by recording from the severed rami with suction electrodes. Innervation patterns of regenerated fields were influenced by graft borders and adjacent fields. Misdirected reflexes were found for ventral skin on the dorsal side only when innervated by ventral rami in a manner never seen in normal or sham operated animals. This suggested that selective reinnervation has occurred.

Development of locomotor behavior in wild type and spastic (sp/sp) axolotls, Ambystoma mexicanum

The homozygous recessive spastic mutant found in the Mexican axolotl shows violent coiling and thrashing behavior when subjected to strong tactile or electrical stimulation. In order to establish the time of onset of the first behavioral manifestation of the spastic gene, an etiological analysis of the ontogeny of swimming behavior in mutants and wild type siblings was undertaken. The locomotor patterns shown by embryos in response to an electrical stimulus were analyzed quantitatively from the embryonic early flexure stage through the larval early feeding stage. Spastic larvae failed to show dorsal-up swimming frequencies equal to those of sibling controls from day 12 (Harrison stage 40) of development indicating a lack of equilibrium. Both spastics and their siblings showed "sinusoid swimming" and "coiling" behavior in response to an aversive stimulus through day 18 (Harrison state 46, early feeding stage) of development. From day 18, wild type siblings abruptly decreased "coiling" behavior and showed strong "escape swimming" in response to an intense stimulus. Spastics never developed "escape swimming" patterns but retained a mixture of "sinusoid swimming" and "coiling" patterns characteristic of pre-feeding stage larvae.

Naproxen and aspirin in rheumatoid arthritis: a multicenter double-blind crossover comparison study

One hundred nineteen adults with active definite or classical rheumatoid arthritis were studied in a multicenter double-blind crossover study of naproxen (500 mg/day) and aspirin (3.6 Gm/day). Each drug was given in sequence for a six-week study period. Patients already receiving corticosteriod and/or gold therapy were maintained at constant dose throughout the study, but analgesics and other nonsteroidal antiinflammatory agents were discontinued at baseline. Objective and subjective evaluations by both investigator and patient were carried out at two-week intervals. No significant difference in global evaluation of efficacy or individual measures of efficacy was observed between aspirin and naproxen therapy, although physicians' global evaluation tended to favor naproxen. Sedimentation rate was lower on aspirin (naproxen 43.1 mm/hr; aspirin 38.7 mm/hr; P=0.02). Naproxen, 250 mg twice daily, was significantly better tolerated than aspirin, 900 mg four times daily. Mild, moderate, and severe side effects were less frequent with naproxen. The incidence of heartburn was significantly lower on naproxen, and significantly fewer patients terminated their six-week study period on naproxen than on aspirin. There were no significant deviations from baseline values in hematocrit, white cell or differential counts, or in tests of renal and hepatic function during the course of the study.