Immunization with gp96 from Listeria monocytogenes-infected mice is due to N-formylated listerial peptides

N-Formylated (N-f-met) peptides derived from proteins of the intracellular bacterium Listeria monocytogenes generate a protective, H2-M3-restricted CD8 T cell response in C57BL/6 mice. N-f-met peptide-specific CTL were generated in vitro when mice previously immunized with gp96 isolated from donor mice infected with L. monocytogenes were stimulated with these peptides. No significant peptide-specific CTL activity was observed in mice immunized with gp96 from uninfected animals. Masses corresponding to one N-f-met peptide were found by matrix-assisted laser desorption/ionization-mass spectrometry on gp96 isolated from C57BL/6 mice infected with L. monocytogenes, but not on gp96 from noninfected mice. Therefore, bacterial N-f-met peptides from intracellular bacteria can bind to gp96 in the infected host, and gp96 loaded with these peptides can generate N-f-met-peptide-specific CTL. We assume a unique role of gp96 in Ag processing through the H2-M3 pathway.

Role of CD28 for the generation and expansion of antigen-specific CD8(+) T lymphocytes during infection with Listeria monocytogenes

Infection of mice with the intracellular bacterium Listeria monocytogenes results in a strong CD8(+) T cell response that is critical for efficient control of infection. We used CD28-deficient mice to characterize the function of CD28 during Listeria infection, with a main emphasis on Listeria-specific CD8(+) T cells. Frequencies and effector functions of these T cells were determined using MHC class I tetramers, single cell IFN-gamma production and Listeria-specific cytotoxicity. During primary Listeria infection of CD28(-/-) mice we observed significantly reduced numbers of Listeria-specific CD8(+) T cells and only marginal levels of specific IFN-gamma production and cytotoxicity. Although frequencies were also reduced in CD28(-/-) mice during secondary response, we detected a considerable population of Listeria-specific CD8(+) T cells in these mice. In parallel, IFN-gamma production and cytotoxicity were observed, revealing that Listeria-specific CD8(+) T cells in CD28(-/-) mice expressed normal effector functions. Consistent with their impaired CD8(+) T cell activation, CD28(-/-) mice suffered from exacerbated listeriosis both after primary and secondary infection. These results demonstrate participation of CD28 signaling in the generation and expansion of Ag-specific CD8(+) T cells in listeriosis. However, Ag-specific CD8(+) T cells generated in the absence of CD28 differentiated into normal effector and memory T cells.

Autologous antileukemic immune response induced by chronic lymphocytic leukemia B cells expressing the CD40 ligand and interleukin 2 transgenes

Although the B cells of chronic lymphocytic leukemia (B-CLL cells) express both tumor-specific peptides and major histocompatibility complex (MHC) class I antigens, they lack the capacity for costimulatory signaling, contributing to their protection against host antitumor immunity. To stimulate CLL-specific immune responses, we sought to transfer the human CD40 ligand (hCD40L) gene to B-CLL cells, using an adenoviral vector, in order to upregulate costimulating factors on these cells. Because efficient gene transduction with adenoviral vectors requires the expression of virus receptors on target cells, including the coxsackievirus B-adenovirus receptors (CAR) and alpha(v) integrins, we cocultured B-CLL cells with human embryonic lung fibroblasts (MRC-5 line). This exposure led to increased expression of integrin alpha(v)beta3 on B-CLL cells, which correlated with higher transduction rates. Using this novel prestimulation system, we transduced B-CLL cells with the hCD40L gene. The Ad-hCD40L-infected cells had higher expression of B7 molecules and induced activation of autologous T cells in vitro, but these T cells could not recognize parental leukemic cells. By contrast, an admixture of Ad-hCD40L-positive cells and leukemic cells transduced with the human interleukin 2 (IL-2) gene produced greater T cell activation than did either immunostimulator population alone. Importantly, this combination generated autologous T cells capable of specifically recognizing parental B-CLL cells. These findings suggest that the combined use of genetically modified CD40L-expressing B-CLL cells in combination with IL-2-expressing B-CLL cells may induce therapeutically significant leukemia-specific immune responses.

Immunity against Helicobacter pylori: significance of interleukin-4 receptor alpha chain status and gender of infected mice

Vaccination of interleukin-4 (IL-4) receptor alpha (IL-4Ralpha) chain-deficient BALB/c mice with Helicobacter pylori urease and cholera toxin or with urease-expressing, live attenuated Salmonella enterica serovar Typhimurium cells revealed that protection against H. pylori infection is independent of IL-4- or IL-13-mediated signals. A comparison of male and female mice suggests a sexual dimorphism in the extent of bacterial colonization that is particularly evident in the absence of the IL-4Ralpha chain.

Targeting of the pro-apoptotic VDAC-like porin (PorB) of Neisseria gonorrhoeae to mitochondria of infected cells

Infection of cell cultures with Neisseria gonorrhoeae results in apoptosis that is mediated by the PorB porin. During the infection process porin translocates from the outer bacterial membrane into host cell membranes where its channel activity is regulated by nucleotide binding and voltage-dependent gating, features that are shared by the mitochondrial voltage-dependent anion channel (VDAC). Here we show that porin is selectively and efficiently transported to mitochondria of infected cells. Prevention of porin translocation also blocked the induction of apoptosis. Mitochondria of cells treated with porin both in vitro and in vivo were depleted of cytochrome c and underwent permeability transition. Overexpression of Bcl-2 blocked porin-induced apoptosis. The release of cytochrome c occurred independently of active caspases but was completely prevented by Bcl-2. Our data suggest that the Neisseria porin can, like its eukaryotic homologue, function at the mitochondrial checkpoint to mediate apoptosis.

Adenosine challenge and boost protocols: new tools for myocardial perfusion imaging

The validity of pharmacologic stress testing and subsequent myocardial perfusion imaging is uncertain in those patients who may have taken caffeine within the 24 hours before testing. For such patients, two new challenge tests have been developed. An intravenous bolus dose of adenosine is given at a dose of 6 mg in a period of 1 or 2 seconds. A physiologic response qualifies the patient to proceed with the scheduled stress test. In the occasional patient who exhibits no pharmacologic symptoms during an infusion test, a similar bolus dose of 6 mg adenosine can validate perfusion tests. These two applications are successful regardless of whether adenosine or dipyridamole infusions are performed. Based on this multicenter experience over 4 years, the authors estimate that 5% to 10% of patients undergoing pharmacologic testing are appropriate candidates for a challenge test.

Assessment of coronary artery patency after stent placement using magnetic resonance angiography

The ability to noninvasively assess the patency of coronary stents would represent a significant advance. We evaluated the safety and ability of two-dimensional coronary MR angiography in imaging stents and suggesting patency. Coronary MR angiography of 26 coronary stents (Palmaz-Schatz) was performed in 16 patients 39 to 73 years of age. Studies were performed between 2 and 4 months after stent placement. All patients were symptom free at the time of imaging. Coronary MR angiography was performed with a commercial 1.5-T MR imager using an electrocardiographically gated pulse sequence with breath-holding. Images were obtained in mid-diastole with and without fat suppression. Image artifacts caused by the metal in the stents were clearly visualized in all 26 stents (100% sensitivity for stent detection). Arterial flow signal was seen in the coronary artery or graft distal to the stent in 25 of 26 cases (96%). All patients, except for the one in which distal flow could not be seen, remained symptom free for >2 years. The distribution of stent locations was as follows: 10 in the right coronary artery (RCA), 10 in the left anterior descending coronary artery (LAD), 2 in the left circumflex coronary artery, and 4 in saphenous vein grafts (SVGs) to RCA. One patient had 2 RCA and 2 LAD stents, one had 3 RCA and 1 LAD stents, one had 3 SVG stents, and two had double RCA stents. Coronary MR angiography is safe for noninvasive imaging of coronary stents, and in the proper clinical setting, it can be used to help suggest patency.

Tubularized incised plate hypospadias repair for proximal hypospadias

PURPOSE

We report a multicenter experience using tubularized incised plate urethroplasty for proximal hypospadias.

MATERIALS AND METHODS

From August 1993 to December 1996 tubularized incised plate urethroplasty was performed in 27 boys 6 months to 3 years old with mid shaft and penoscrotal hypospadias. In 7 other boys complex reconstruction combined the tubularized incised plate technique for the glanular urethra with other repairs for the proximal urethra.

RESULTS

Tubularized incised plate surgery created a functional neourethra even in penoscrotal hypospadias. Complications of the primary repair developed in only 3 of 27 patients (11%). No complications were attributed to use of the technique for the glanular urethra in complex repairs.

CONCLUSIONS

Tubularized incised plate urethroplasty is a versatile operation that corrects proximal hypospadias defects with few complications and superior cosmetic results.

Tubularized incised plate hypospadias repair for proximal hypospadias

PURPOSE

We report a multicenter experience using tubularized incised plate urethroplasty for proximal hypospadias.

MATERIALS AND METHODS

From August 1993 to December 1996 tubularized incised plate urethroplasty was performed in 27 boys 6 months to 3 years old with mid shaft and penoscrotal hypospadias. In 7 other boys complex reconstruction combined the tubularized incised plate technique for the glanular urethra with other repairs for the proximal urethra.

RESULTS

Tubularized incised plate surgery created a functional neourethra even in penoscrotal hypospadias. Complications of the primary repair developed in only 3 of 27 patients (11%). No complications were attributed to use of the technique for the glanular urethra in complex repairs.

CONCLUSIONS

Tubularized incised plate urethroplasty is a versatile operation that corrects proximal hypospadias defects with few complications and superior cosmetic results.

Persistent eustachian valves in infants: course and management in symptomatic patients

Although commonly found on echocardiograms, persistent Eustachian valves rarely result in clinical symptoms in newborns and infants without other significant structural heart disease. Previous reports have suggested that such patients require surgical treatment. The goal of this study is to delineate better the clinical course in infants presenting with symptoms that are a result of persistent Eustachian valves. A review of all patients with symptoms attributed to persistent Eustachian valves over a 10-year period at Riley Hospital for Children showed 3 of 4 patients improved, with eventual resolution of symptoms, with conservative management alone. This suggests that, contrary to previous reports, clinical observation may be warranted in many of these infants.

Functional characterization of the N-glycosylation sites of human acid sphingomyelinase by site-directed mutagenesis

Most soluble lysosomal enzymes require a mannose-6-phosphate recognition marker present on asparagine-linked oligosaccharides for proper targeting to lysosomes. We have determined the influence of the six potential N-linked oligosaccharide chains of human acid sphingomyelinase (ASM) on catalytic activity, targeting, and processing of the enzyme. Each N-glycosylation site was modified by site-directed mutagenesis and subsequently expressed in COS-1 cells. Evidence is presented that five of these sites are used. Elimination of the four N-terminal glycosylation sites does not disturb lysosomal targeting, processing, or enzymatic activity. However, removal of the two C-terminal N-glycosylation sites inhibits the formation of mature enzyme. Absence of glycosylation site five resulted in rapid cleavage of the primary translation product to an enzymatically inactive protein which accumulated inside the endoplasmic reticulum/Golgi, whereas deletion of glycosylation site six led to the formation of an inactive ASM precursor, also retained inside the endoplasmic reticulum/Golgi. Our results also provide evidence that the site of early proteolytic cleavage of newly synthesized ASM must be located between the second and third glycosylation sites.

Purification of acid sphingomyelinase from human placenta: characterization and N-terminal sequence

Human placental acid sphingomyelinase (ASM) was purified by sequential chromatography on Con A-Sepharose, octyl-Sepharose and Matrex gel red A. Final purification to apparent homogeneity was achieved by immunoaffinity chromatography employing polyclonal anti-ASM antibodies. The antibodies also allowed specific detection of ASM by Western blotting at various stages of purification. The ASM activity was enriched about 110,000-fold over that of the crude extract, yielding an enzyme preparation with a specific activity of about 1 mmol/h per mg protein in a detergent-containing assay system. Analysis of the final preparation by SDS-PAGE resulted in a single protein band with a molecular mass of approximately 75 kDa, which was reduced to approximately 60 kDa after complete deglycosylation. Microsequencing of the purified ASM revealed the N-terminal amino acid sequence of the mature placental enzyme.

Biosynthesis, processing, and targeting of sphingolipid activator protein (SAP )precursor in cultured human fibroblasts. Mannose 6-phosphate receptor-independent endocytosis of SAP precursor

Sphingolipid activator proteins (SAPs) are essential cofactors for the lysosomal degradation of glycosphingolipids with short oligosaccharide chains by acidic exohydrolases. SAP-A, -B, -C, and -D derive from proteolysis of a 73-kDa glycoprotein, the SAP precursor. In the present publication, we studied the intracellular transport and the endocytosis of SAP precursor in human skin fibroblasts. Our data indicate that SAP precursor bears phosphate residues on noncomplex carbohydrate chains linked to the SAP-C and the SAP-D domain and sulfate residues on complex carbohydrate chains located within the SAP-A, -C, and possibly the SAP-D domain. Treatment of fibroblasts with either bafilomycin A1 or 3-methyladenine indicates that proteolytic cleavage of SAP precursor begins as early as in the late endosomes. To determine whether targeting of SAP precursor depends on mannose 6-phosphate residues, we analyzed the processing of SAP precursor in I-cell disease fibroblasts. In these cells nearly normal amounts of newly synthesized SAP-C were found, although secretion of SAP precursor was enhanced 2-3-fold. Moreover, SAP-C could be localized to lysosomal structures by indirect immunofluorescence in normal and in I-cell disease fibroblasts. Mannose 6-phosphate was not found to interfere significantly with endocytosis of SAP precursor. Normal fibroblasts internalized SAP precursor secreted from I-cells nearly as efficiently as the protein secreted from normal cells. To our surprise, deglycosylated SAP precursor was taken up by mannose 6-phosphate receptor double knock out mouse fibroblasts more efficiently than the glycosylated protein. We propose that intracellular targeting of SAP precursor to lysosomes is only partially dependent on mannose 6-phosphate residues, whereas its endocytosis occurs in a carbohydrate-independent manner.

Tubularized incised plate hypospadias repair: results of a multicenter experience

PURPOSE

We report a multicenter experience using tubularized incised plate urethroplasty to correct distal hypospadias.

MATERIALS AND METHODS

A total of 148 patients underwent repair by 6 pediatric urologists at different institutions in the United States and Europe.

RESULTS

Tubularized incised plate repair created a functional neourethra with a vertically oriented meatus. Complications, including meatal stenoses and fistulas, occurred in 10 patients (7%).

CONCLUSIONS

Tubularized incised plate urethroplasty can be performed in most cases of distal hypospadias. Cosmetic results are superior to those of other popular techniques.

Molecular analysis of the acid sphingomyelinase deficiency in a family with an intermediate form of Niemann-Pick disease

A novel point mutation in the lysosomal acid sphingomyelinase gene has been identified in the recently reported Serbian family with a clinically and biochemically atypical intermediate form of Niemann-Pick disease. The mutation was a T1171-->G transversion resulting in substitution of glycine for normal tryptophan at amino acid residue 391. The coding sequence was otherwise normal. All of the five affected individuals were almost certainly homoallelic, and both of the two obligate heterozygotes studied also carried the same mutation. This mutation is therefore likely to be directly associated with the atypical phenotype of these patients. Expression in COS-1 cells suggested a higher residual activity than that in cultured fibroblasts. A recently developed high-affinity rabbit antihuman sphingomyelinase antibody allowed us to study for the first time the biosynthesis, processing, and targeting of a mutant sphingomyelinase by metabolic labeling of cultured fibroblasts. The mutant enzyme protein was normally synthesized, processed, and routed to the lysosome but was apparently unstable and degraded rapidly once it reached the lysosome. Together with the finding of the relatively high residual activity in COS-1 cells, we interpret our observations to mean that instability and rapid breakdown of the mature mutant enzyme protein, due to the mutation rather than direct inactivation of the catalytic activity, is the primary mechanism for the deficiency of sphingomyelinase activity in these patients. A high prevalence of this mutation in the Serbian population is likely, since the family pedigree indicates that members from four reportedly unrelated families must have contributed the same mutation.

Purification, characterization, and biosynthesis of human acid ceramidase

Acid ceramidase (N-acylsphingosine deacylase, EC 3.5.1.23) is the lysosomal enzyme catalyzing the hydrolysis of ceramide to sphingosine and free fatty acid. Its inherited deficiency causes ceramide accumulation in Farber's disease. The enzyme was purified to apparent homogeneity from human urine by sequential chromatography on octyl-Sepharose, concanavalin A-Sepharose, blue-Sepharose, and DEAE-cellulose. The final preparation, which was enriched approximately 4450-fold over the starting material, resulted in a polypeptide of approximately 50 kDa and could be reduced into two subunits of approximately 13 (alpha) and approximately 40 (beta) kDa. Treatment of the purified enzyme with endoglycosidase H or peptido-N-glycanase F reduced the molecular mass of the beta subunit to approximately 30-35 and approximately 27 kDa, respectively. In contrast, the molecular mass of the alpha subunit was unchanged. The purified enzyme had an apparent Km of 149 microM and a Vmax of 136 nmol/mg/h using N-lauroylsphingosine as substrate. Polyclonal antibodies were raised against the purified urinary enzyme and used to investigate the biosynthesis of acid ceramidase. Immunoprecipitation studies on metabolically labeled skin fibroblasts indicated that both subunits arose from a single precursor of approximately 55 kDa. A minor portion of newly synthesized acid ceramidase was secreted into the medium as a monomeric 47-kDa protein, indicating that generation of the mature heterodimeric enzyme occurred in endosomal and/or lysosomal compartments.

Occurrence of two molecular forms of human acid sphingomyelinase

Human acid sphingomyelinase (ASM) hydrolyses sphingomyelin to ceramide and phosphocholine. Metabolic studies on COS-1 cells transfected with ASM cDNA revealed the occurrence of an enzymically inactive precursor which is differentially processed to two predominant native glycoprotein forms: a 70 kDa polypeptide corresponding to human urinary protein and a 57 kDa form. Formation of these potentially active forms was shown to be restricted to distinct compartments. Maturation of the ASM precursor to a predominant 70 kDa form occurs exclusively inside acidic organelles, whereas variable amounts of 57 kDa ASM are detectable immediately after biosynthesis. Metabolic labelling of transfected COS-1 cells with [32P]Pi further suggests that this form obviously does not carry oligomannosylphosphate residues, in contrast with the mature lysosomal ASM. In order to verify that this early form of active ASM results from co-post-translational proteolysis of the ASM precursor and not from the use of different translation-initiation sites on the ASM mRNA, appropriate 5'-mutagenized cDNA constructs were transiently expressed. These results clearly indicate that the first potential in-frame AUG is exclusively used for translation initiation in vivo and that deletion of the proposed signal sequence for endoplasmic reticulum import completely eliminates the ability of the translation product to enter the vacuolar apparatus. As there are two different subcellular sites of maturation of the ASM precursor, and intracellular targeting of the two processed forms appears to be different, the two ASM proteins may contribute to distinct physiological functions.

The tricyclic antidepressant desipramine causes proteolytic degradation of lysosomal sphingomyelinase in human fibroblasts

The effect of the tricyclic antidepressant desipramine on the processing of lysosomal sphingomyelinase (EC 3.1.4.12) was investigated by pulse-chase studies on [35S]methionine labeled cultured human skin fibroblasts. Desipramine induced rapid intracellular degradation of mature acid sphingomyelinase when added to the cells in the micromolar range, concomitantly abolishing the enzyme activity. Pulse chase labeling revealed the disappearance of mature enzyme forms when fibroblasts were treated with 25 microM desipramine. Incubation of cells with 25 microM leupeptin, an inhibitor of thiol proteases, 24 h prior to desipramine intoxication prevented this drug-induced effect. From these results we conclude that desipramine and possibly also similarly acting tricyclic antidepressants induce proteolytic degradation of acid sphingomyelinase.

Processing of human acid sphingomyelinase in normal and I-cell fibroblasts

The biosynthesis of acid sphingomyelinase in normal and I-cell disease fibroblasts was investigated by metabolic labeling with [35S]methionine and immunoprecipitation followed by polyacrylamide gel electrophoresis and fluorography. Two major polypeptides with apparent molecular masses of 75 and 72 kDa (peptide chains of 64 and 61 kDa, respectively) and a minor one with molecular mass of 57 kDa (peptide chain of 47 kDa) were found intracellularly soon after pulse labeling. The 75-kDa form is assumed to be the propropolypeptide of sphingomyelinase which is converted into the precursor form of 72 kDa. The precursor is subjected to two distinct processing events. A minor part is already cleaved in the endoplasmic reticulum-Golgi complex yielding the beta-endo-N-acetylglucosaminidase H-resistant form of 57 kDa; whereas, the major part of the precursor is processed within 4 h to a 70-kDa mature beta-endo-N-acetylglucosaminidase H-sensitive form of sphingomyelinase, which is subsequently converted into a polypeptide with molecular mass of 52 kDa within a chase of about 20 h. Both the precursor (72 kDa) as well as its early cleavage product of 57 kDa are secreted into the culture medium to a minor extent. Intracellular transport of sphingomyelinase into lysosomes depends on the phosphomannosyl specific receptor by following criteria: (i) about 80% of newly synthesized precursor was secreted in NH4Cl-treated fibroblasts as well as in I-cells, (ii) the maturation of sphingomyelinase was inhibited in normal fibroblasts exposed to NH4Cl as well as in I-cell fibroblasts, and (iii) the [32P]phosphate associated with oligosaccharides was cleavable by beta-endo-N-acetylglucosaminidase H. However, endocytosis of radiolabeled extracellular precursor by fibroblasts was not prevented by the addition of mannose 6-phosphate, whereas uptake of arylsulfatase A and beta-hexosaminidase was almost completely blocked under these conditions. This indicates that endocytosis of acid sphingomyelinase by cultured fibroblasts might be mediated by an alternative pathway.

Molecular genetics of GM2-gangliosidosis AB variant: a novel mutation and expression in BHK cells

The GM2 activator is a hexosaminidase A-specific glycolipid-binding protein required for the lysosomal degradation of ganglioside GM2. Genetic deficiency of GM2 activator leads to a neurological disorder, an atypical form of Tay-Sachs disease (GM2 gangliosidosis variant AB). Here, we describe a G506 to C transversion (Arg169 to Pro) in the mRNA of an infantile patient suffering from GM2-gangliosidosis variant AB. Using the polymerase chain reaction amplification and direct-sequencing technique, we found the patient to be homozygous for the mutation, whereas the parents were, as expected, heterozygous. BHK cells transfected with a construct of mutant cDNA gave no GM2 activator protein detectable by the Western blotting technique, whereas those transfected by a wild-type cDNA construct showed a significant level of human GM2 activator protein. The substitution of proline for the normal Arg169 therefore appears to result in premature degradation of the mutant GM2 activator, either during the post-translational processing steps or after reaching the lysosome. The basis for the phenotype of GM2 gangliosidosis variant AB may therefore be either inactivation of the physiological activator function by the point mutation or instability of the mutant protein.

Guidelines for cardiac monitoring of children during and after anthracycline therapy: report of the Cardiology Committee of the Childrens Cancer Study Group

The anthracycline antibiotics, daunorubicin, doxorubicin, and the newer derivatives, are important components of many antineoplastic chemotherapeutic regimens. Their usefulness is limited by their cardiotoxicity. Sequential monitoring of cardiac function of patients undergoing chemotherapy allows identification of subclinical cardiotoxicity. In many patients monitoring can thus guide the modification of the chemotherapy to minimize cumulative cardiotoxicity, reducing acute and long-term clinical and subclinical sequelae. Such monitoring also aids in the comparison of cardiotoxicity produced by different drugs and different methods and schedules of drug administration. The considerable variability of monitoring regimens between institutions and in the literature has detracted from its usefulness. The Cardiology Committee of the Childrens Cancer Study Group has, therefore, reviewed the field and has formulated recommendations for standardized noninvasive monitoring of children during and immediately after chemotherapy and for the modification of the chemotherapy where indicated.

Simultaneous deficiency of sphingolipid activator proteins 1 and 2 is caused by a mutation in the initiation codon of their common gene

Sphingolipid activator proteins (SAPs) are small, nonenzymic glycoproteins that stimulate lysosomal degradation of various sphingolipids. SAP-1, SAP-2, and two additional potential activator proteins are derived from a common precursor by proteolytic processing. A severe case of sphingolipid storage disease that led to death within 16 weeks was attributed to a possible total deficiency of the SAPs generated by this gene (Harzer, K., Paton, B. C., Poulos, A., Kustermann-Kuhn, B., Roggendorf, W., Grisar, T., and Popp, M. (1989) Eur. J. Pediatr. 149, 31-39). Analysis of the SAP precursor cDNA from the patient and his fetal sibling showed an A to T transversion in the initiation codon. Allele-specific oligonucleotide hybridization revealed that both parents are heterozygous carriers for this mutation. In pulse-chase experiments using antisera raised against SAP-1 or SAP-2, no cross-reacting material could be detected in the patients' fibroblasts.

Soft-tissue sarcomas other than rhabdomyosarcoma in children

Forty-seven children with nonrhabdomyosarcomatous soft-tissue sarcomas (NRSTS) were treated by the Hematology-Oncology Service at Texas Children's Hospital, Houston, Texas, between 1958 and 1990. The male:female ratio was 1:1, and the median age was 11 years (3 weeks-16 years). A preexisting condition was found in 9/47 (19%) patients including neurofibromatosis (3), Down's syndrome (1), spina bifida (1), congenital facial asymmetry (1), giant pigmented nevus (1), juvenile onset diabetes mellitus (1), and acquired immune deficiency syndrome (1). The site of primary tumor was head and neck (3), trunk (33), and extremities (11). Twenty-four patients (51%) have survived free of disease with a median follow-up of 5 years (4 months-22 years). No patient whose disease recurred achieved a second remission. Of the 19 patients with group I disease, 16 (84%) survived free of disease. Wide excision of the primary tumor, with no microscopic residual disease, was associated with the greatest chance of disease-free survival.

Molecular basis of acid sphingomyelinase deficiency in a patient with Niemann-Pick disease type A

Niemann-Pick disease, an autosomal recessive lysosomal storage disorder, is caused by deficiency of acid sphingomyelinase. Sequence analysis of mRNA and genomic DNA of fibroblasts of a type A patient showed a single G1729 to A nucleotide transition. This mutation resulted in a substitution of serine for normal glycine at position 577 of the peptide sequence. Amplification of the genomic DNA region around the mutation and subsequent sequencing yielded exclusively the same base change found at the cDNA level. Expression studies with this abnormal cDNA in COS-1 cells revealed a complete loss of enzymatic activity of the mutated protein. These findings indicate that this mutation is responsible for the clinical disease of the patient.

Affinity purification of the photoreceptor cGMP-gated cation channel

The cGMP-gated cation channel is a member of a new family of channel proteins that appear to be directly regulated by cyclic nucleotides. A protein with a subunit molecular mass of 78 kDa that exhibits cGMP-gated calcium flux when reconstituted into phospholipid-containing vesicles has been purified using 8-bromo-cGMP-agarose affinity chromatography. This channel activity is sensitive to the inhibitor l-cis-diltiazem. Treatment of the reconstituted channel with trypsin abolishes the l-cis-diltiazem sensitivity. Apparent endogenous proteolysis can also result in smaller molecular weight polypeptides that exhibit cGMP-gated channel activity but are insensitive to l-cis-diltiazem. These results show that the channel can bind cGMP and that it contains a l-cis-diltiazem inhibitory domain that is distinct from the cGMP-binding domain.

Congenital aneurysm of the left atrial wall in infancy

A 5-month-old male infant with congenital left atrial aneurysm is reported. The youngest patient previously reported was 2 1/2 years old. This case is unusual because the patient was an infant and because of the degree of mitral insufficiency and acute cardiac decompensation observed in the patient.

Acoustic analysis of gradient-coil noise in MR imaging

A survey was conducted of acoustic noise levels in magnetic resonance (MR) imaging systems. Static magnetic flux and radio-frequency pulses did not affect the function of shielded sound-pressure detection equipment. Noise levels were measured at bore isocenter during a variety of imaging sequences in six MR imaging systems with magnetic fields of 0.35-1.5 T. Measured noise ranged from 82 to 93 dB on the A-weighted scale and from 84 to 103 dB on the linear scale. Noise levels increased during sequences employing thinner section thickness and shorter repetition and echo times and were independent of field strength. Gradient-coil noise in MR imaging is an annoyance but is well within safety guidelines.

Use of maximal expiratory flows to evaluate central airways obstruction in infants

Partial expiratory flow-volume (PEFV) curves obtained by the rapid compression technique were employed to assess airway function in three infants with three different lesions of the central airways (vascular ring, congenital tracheal stenosis, subglottic polyp). Preoperatively, all three demonstrated severe flow limitation with a relatively constant forced expiratory flow over the tidal volume range. Postoperatively the PEFV curves changed to a normal convex shape, and the maximal expiratory flows at functional residual capacity (VmaxFRC) returned to normal. The PEFV curve adds to our physiologic assessment of the severity of the central airway obstruction in infants and to the efficacy of our therapeutic intervention.

Resection of advanced stage neuroblastoma with the cavitron ultrasonic surgical aspirator

Current protocols for the treatment of neuroblastoma emphasize total or near total resection of tumor to improve survival. This is preferentially performed as a primary procedure, or is attempted at a second-look operation. Unfortunately, this tumor often grows to large size with invasion of the spinal canal, or encasement of major vascular or other retroperitoneal structures. A primary attempt at complete removal may result in difficult-to-control hemorrhage or injury to, or loss of, vital organs. A second-look procedure carries other intrinsic risks. It often must be performed during a period of chemotherapeutically induced hematologic and immunologic suppression. The presence of adhesions and dense scar tissue increases the complexity of the dissection. The Cavitron Ultrasonic Surgical Aspirator (CUSA) combines continuous fragmentation, irrigation, and aspiration in one instrument. Tissues high in water content are selectively fragmented and aspirated, while tissues high in collagen and elastin (such as blood vessels and pseudocapsular walls) are selectively spared. Five patients, two with large pelvic dumbell tumors, two with large intrathoracic tumors, and one with a seemingly unresectable large right adrenal tumor (crossing the midline with extensive aortocaval nodal involvement) had total or near-total resection accomplished using the CUSA. In these patients, initial resection of the relatively soft inner part of the tumor left a collapsed pseudocapsule, which was then removed under greatly improved exposure in a relatively small field. The constant aspiration virtually eliminated tumor spillage. Since most vessels were skeletonized without penetration, total blood loss was minimized. There were no intraoperative or postoperative complications.

Development of arginine-synthesizing enzymes in mouse intestine

The urea biosynthetic pathway functions in mammalian liver to convert excess ammonia to urea and to maintain the concentration of ammonia in blood at nontoxic levels. This action is accomplished by enzymatic adaptation to quantitative changes in dietary protein. The first two enzymes of the pathway are found in the intestine of the adult mouse, but they do not adapt to dietary change. The enzymes in the intestine produce citrulline, which is carried by the bloodstream to the kidney, where it is converted by the next two enzymes of the pathway to arginine. This mechanism serves as the major source of circulating arginine. We have demonstrated that, at birth, the arginine-synthesizing enzymes in the kidney of the C57Bl/6 mouse are minimally developed, whereas in the intestine activity of carbamoyl-phosphate synthase is elevated and argininosuccinate synthase and lyase, usually present only in trace quantities in the adult intestine, are markedly increased in the newborn. The arginine formed cannot be converted to urea, since arginase does not appear in intestinal cells of the mouse until the age of 15 days. Except for liver, intestine has the most rapid protein turnover of any normal tissue. Our study indicates that, at a time when no other endogenous source of arginine for protein synthesis is available, the intestine of the newborn C57Bl mouse is capable of synthesizing arginine from either citrulline or NH3 and CO2.

Hormonal therapy of cryptorchidism. A randomized, double-blind study comparing human chorionic gonadotropin and gonadotropin-releasing hormone

We conducted a randomized, double-blind study comparing intranasal gonadotropin-releasing hormone (1.2 mg per day for 28 days) with parenteral human chorionic gonadotropin (3300 IU per week for four weeks) in the treatment of cryptorchidism in 33 boys one to five years old (29 with unilateral and 4 with bilateral cryptorchidism). Testicular descent into the scrotum occurred in 3 of the 16 patients (19 percent) treated with gonadotropin-releasing hormone and in 1 of the 17 (6 percent) treated with human chorionic gonadotropin (P = 0.23). The mean luteinizing hormone and testosterone levels were similar in both groups before treatment. During treatment, the testosterone levels were significantly increased in both groups, but higher levels occurred in the group treated with human chorionic gonadotropin (P less than 0.05). In a parallel (but uncontrolled) study of five boys with retractile testes (defined as a nonscrotal testis that could be manipulated into the bottom of the scrotum) who were originally excluded from the main protocol but were treated with the same regimen of human chorionic gonadotropin, descent into the scrotum occurred in all patients. We conclude that hormonal therapy with either gonadotropin-releasing hormone or human chorionic gonadotropin is, in most cases, ineffective in promoting testicular descent of true cryptorchid testes. However, short-term treatment with human chorionic gonadotropin is very effective in producing descent of retractile testes. These results suggest that the wide discrepancies in apparent efficacy in previous trials of hormonal therapy of cryptorchidism may have been due to inclusion in those studies of various proportions of patients with retractile testes.

Surgery for discrete subvalvular aortic stenosis: actuarial survival, hemodynamic results, and acquired aortic regurgitation

Discrete membranous subaortic stenosis (DMSS) accounts for 8 to 30% of congenital left ventricular outflow obstruction. The immediate effectiveness of surgical resection of this discrete obstructing membrane has been well documented, but little has appeared regarding late clinical and hemodynamic follow-up. Fifty-three patients with DMSS underwent operation at our institution from 1957 to 1983. Most (78%) were symptomatic, 79% had left ventricular hypertrophy (LVH) by electrocardiogram, and 92% had roentgenographic evidence of cardiomegaly preoperatively. Catheterization revealed a mean preoperative left ventricular-aortic gradient of 89 mm Hg. Twenty-eight patients had associated aortic insufficiency (AI) on the initial aortogram. Seven patients acquired AI in the interim between the first and second preoperative catheterization. Our patients have been followed for up to 12 years postoperatively. There have been 2 early and 3 late deaths. (Actuarial analysis revealed 5- and 10-year survival of 95% and 83%, respectively.) Seventy-one percent of the previously symptomatic patients noted relief of their preoperative complaints, and 45% of those with LVH had a regression in voltage. Cardiomegaly as determined by chest roentgenogram decreased in 45%. The left ventricular-aortic gradient fell to an average of 35 mm Hg a year postoperatively. Surgical treatment of congenital subvalvular aortic stenosis is effective in reducing the preoperative symptoms and the left ventricular-aortic gradient. It appears that DMSS causes AI.

Radionuclide angiocardiography in children

Clinical use of radiotracer techniques in pediatric cardiology is increasing. Three basic methods being employed are first pass radionuclide angiocardiography, gated blood pool scanning and myocardial perfusion scintigraphy. These methods are rapid, safe and accurate. They are minimally invasive and result in a low radiation dose to the patient. The development of ultrashort-lived radionuclides (such as iridium-191m with a half-life of only 5 seconds), improvements in nuclear imaging instrumentation and numerical analysis should contribute to a further utilization of these methods.

Femoral artery spasm in children: catheter size is the principal cause

The incidence of femoral artery spasm and subsequent thrombosis complicating angiography is greater in children than adults. This study was designed to assess femoral artery spasm and to determine its causes in children. In 100 unselected, consecutive infants and children undergoing left heart angiocardiography by the Seldinger technique, angiography of the femoral artery was performed to include the puncture site after completion of angiocardiography. Arterial spasm was quantified and, with mathematical analysis, related to various clinical and angiographic factors. Some degree of arterial spasm was noted in 62% of all cases; it was more frequent and severe in neonates. Although it was more intense in the infant with a small femoral artery, analysis of the data indicates that patient age, weight, length of catheterization, size of femoral artery, and catheter size have only minimal relative importance in the occurrence and severity of arterial spasm. The most important factor in spasm is the relative size of catheter to artery.

Monitoring intravenous fat emulsions in neonates with the fatty acid/serum albumin molar ratio

Weekly determinations of the fatty acid/albumin molar ratio (FA/SA) were obtained 136 times on 50 neonates (birthweight range, 675-4300 grams; median, 1360 grams) to determine if our use of intravenous fat (IVF) was putting these newborns at risk for kernicterus. The FA/SA was measured using a convenient spectrophotometric technique which we have previously described (Berde CB, Kerner JA, Johnson JD: Clin Chem 26:1173-1177, 1980). Twenty-nine infants received IVF with doses from 0.5 to 3.3 gram/kilogram/day (mean 1.5 gram/kilogram/day), given over 24 hours whenever possible, most commonly begun in the second week of life when the bilirubin level was less than one half of the potential exchange level. Twenty-one infants received no IVF. Previous studies show that fatty acids do not begin to displace bilirubin from albumin until the FA/SA is greater than 6 in vivo, and greater than 4 in vitro. All our infants had safe values with mean FA/SA values of approximately 1.0. Continuous IVF as we administer it does not place neonates at risk for kernicterus. Centers administering IVF in the first week of life or by bolus should consider close monitoring of their infants with the FA/SA.

Evolution of cultured leukemic cell lines monitored by chromosomal and immunologic analysis

We have investigated the karyotypes and markers of B lymphocyte differentiation in two leukemic cell lines, NALM-6-B and NALM-6-MI, both derived from a patient with non-T, non-B acute lymphoblastic leukemia. Both possess characteristics of thymus-independent, bursal-equivalent (B) lymphocytes. By means of immuno-fluorescence techniques, NALM-6-B was shown to possess 47% surface membrane immunoglobulin-positive (Slg+) cells, while NALM-6-MI is surface membrane immunoglobulin-negative (Slg-), but does possess cytoplasmic immunoglobulin M (ClgM+) in more than 90% of the cells. The Slg- ClgM+ phenotype, coupled with morphologic features, is consistent with NALM-6-MI being arrested at a stage early in B-lymphocyte differentiation (a "pre-B" cell). The predominant banded chromosome karyotype of NALM-6-B is pseudodiploid with a translocation of chromosomal material from the long arm of a chromosome 5 to the short arm of a chromosome 12 (5q-/12p+) and a marker Y chromosome. NALM-6-MI possesses the same marker Y chromosome and a deletion of the long arm of chromosome 5(5q-) since in most cells material missing from chromosome 5 does not appear on the short arm of chromosome 12. Within the limits of resolution available with the banding technique, no other karyotypic differences are observed in the two cell lines. The history of the two cell lines, the karyotypic analysis, and the pattern of immunoglobulin markers indicate the possible clonal evolution of NALM-6-MI from NALM-6-B and implicate a portion of the long arm of chromosome 5 in lymphoid differentiation of these leukemic cell lines.

Improved results in newborns undergoing coarctation repair

Among 172 children who underwent repair of coarctation of the thoracic aorta from June 1, 1967, to June 1, 1979, there were 50 who were less than 6 weeks old. A review was undertaken to assess mortality and postoperative residual hypertension in this newborn age group. Forty-five (90%) had one or more associated congenital cardiac lesions, which were repaired or paliated at the time of coarctation repair. The three most common associated lesions were patent ductus arteriosus (74%), atrial septal defect (74%), and ventricular septal defect (62%). Thirty-one newborns underwent resection with parimary end-to-end repair with 8 deaths (26%), and 18 underwent Dacron patch angioplasty and 1 underwent subclavian angioplasty with 4 deaths (21%). Of the 38 survivors, 36 (95%) had good pedal pulses on postoperative clinical examination 3 months to eleven years postoperatively. Seventeen (45%) had upper and lower extremity blood pressure measured; 2 (5%) showed residual upper extremity hypertension (greater than 2 standard deviations above the mean and a gradient less than 20 mm Hg). One of these 2 patients has undergone repeat repair. Based on this low mortality and infrequent need for repeat repair, we advocate aggressive early operation and judicious use of palliative procedures in newborns, when indicated, for associated defects.

Childhood leukemia-lymphoma. Heterogeneity of phenotypes and prognoses

Results are reported on 724 children and adolescents with acute leukemia-lymphoma. One hundred patients had immunologic marker analysis that defined the major phenotypic groups, i.e., T-cell, B-cell (Burkitt), myeloid, and the most frequent form, non-T, non-T "common" or "undifferentiated" acute leukemia. Pre-T, pre-B, and "null" leukemias are included in the latter group. Response to therapy and survival was best in non-T, non-B acute lymphocytic leukemia, intermediate in T-cell disease, and worst in B-cell (Burkitt) disease. Additional factors resulting in decreased survival include elevated peripheral leukocyte count, presence of enlarged nodes, less depression of hemoglobin and platelets, and age greater than 7 years (all associated with 'lymphomatous" disease). Other factors resulting in decreased survival include age under 3 years and depression of serum immunoglobulins. Definition of the heterogeneity of childhood leukemia-lymphoma dictates differing forms of therapy for the various types of these diseases.

Lactose malabsorption among adult Indians of the Great Basin and American Southwest

The prevalence of primary adult lactose malabsorption and the pattern of milk use were studied among 109 Indians from various tribes of the American Great Basin and Southwest. Included were 100 persons who reported being full-blooded Indians as well as three with Mexican admixture and 6 with some European ancestry. Lactose malabsorption was found in 92% of the full-blooded Indians but in only 50% Indians who acknowledged European admixture. These results agree with those of studies of native Americans done elsewhere which show very high prevalences of such lactose malabsorption among adults reported as fullblooded and lower prevalences among individuals with admitted European ancestors. The suggestion made is that in pre-Colombian times, before interbreeding with Europeans began on any scale, such lactose malabsorption may have been nearly universal among native American adults. Most of the Indians studied consumed abundant milk since childhood but were nevertheless predominantly malabsorbers as adults. This argues against the induction hypothesis advanced by some to explain the striking ethnic differences that occur around the world in primary adult lactose malabsorption.

Lactose malabsorption among the Pima indians of Arizona

Lactose loading tests and other means were used to determine the pattern of primary "adult" lactose malabsorption (LM) and milk use among 171 subjects, including 122 children and 49 adults, almost all of them Pima Indians of Arizona. LM develops at quite young ages in full-blooded Pima children: already in the 3- to 4-year age group, 40% had LM. Of 62 full-blooded Indians (greater than or equal to 4 years of age), 59 (95%) had LM. Of 41 Indians (greater than or equal to 4 years) who were of mixed Indian-northern European ancestry, however, only 25 (61%) had LM, and, among them, prevalence of LM correlated with degree of northern European admixture. Whereas only 21% of Pima lactose absorbers reported symptoms after the loading test, 72% of malabsorbers did so, with older malabsorbers more likely to experience symptoms. In their everyday lives, only 23% of malabsorbers recognized symptoms brought on by milk consumption, but the percentage of malabsorbers making such an association increased with age. Nevertheless the Pima, adults as well as children, continue to drink reasonable quantities of milk. Family pedigrees are consistent with the hypothesis that adult lactose absorption is inherited as an autosomal dominant trait. Over-all results of this study, moreover, support the geographic hypothesis advanced to explain ethnic or racial differences in prevalence of LM, rather than the induction hypothesis.

Adaptation of rat pancreatic amylase and chymotrypsinogen to changes in diet

This study represents an attempt to determine the effect of dietary protein quality and hypophysectomy on the enzymic adaptability of the pancreas in the rat. The specific enzymes studied were amylase, which was purified by immunologic techniques and chymotrypsinogen (activated), which was isolated by affinity column chromatography. Content and synthesis of each enzyme were accurately determined in relation to total pancreatic protein. When rats were fed a 64% sucrose diet (19% casein), there was a two- to three-fold increase in synthesis of amylase. However, if a poor-quality protein (gelatin, gluten, or zein) was substituted for casein, there was no increase in the synthesis of amylase in response to increased carbohydrate. When rats were fed a 19% sucrose diet (64% casein), there was a significant increase in chymotrypsinogen synthesis. Of the poor-quality proteins, gluten was the only one effective in stimulating synthesis of chymotrypsinogen. Peptides, either free or as part of a protein, were necessary for the stimulation of chymotrypsinogen synthesis. Amylase synthesis in hypophysectomized rats was considerably depressed and unresponsibe to increased carbohydrate. This effect could be partially relieved with hydrocortisone, corticosterone, or thyroxin, but not with growth hormone. Hypophysectomy had little effect on synthesis or content of chymotropsinogen.

Asymmetric septal hypertrophy in a large amish kindred

We report a large Amish kindred in which asymmetric septal hypertrophy (ASH) appeared to segregate as an autosomal dominant gene. This kindred was ascertained through a 3-month-old infant and her father. The striking differences between father and daughter regarding clinical presentation and course exemplify the variable expressivity of this condition. The importance of genetic factors in diagnosis and counseling are discussed. Previous reports of ASH in infants and children are reviewed.