Ethnic differences in immune responses to hepatitis B vaccine

A national vaccination program against hepatitis B virus (HBV) to immunize every newborn was initiated in Taiwan in 1986. A serologic survey of 1,812 fully vaccinated children residing in four aboriginal villages and four adjacent nonaboriginal Han Chinese rural villages was conducted in 1993. Children in three of the four aboriginal villages had significantly lower titers of antibody against hepatitis B surface antigen (anti-HBs) than did children in the nonaboriginal villages. Evaluation of cold chain operation for vaccine storage and transport suggested that cold chain failure was not responsible for the fact that children residing in the more remote aboriginal villages had lower mean titers of anti-HBs. However, children whose parents were both aborigines had lower anti-HBs mean titer than did children whose parents were both ethnic Han Chinese. Children of mixed parental origins had intermediate mean titer of anti-HBs. Serologic responses to Japanese encephalitis virus and diphtheria vaccines did not show such correlation with ethnic groups, indicating that the determinant for HBV hyporesponsiveness among the aboriginal children is distinct from that of other childhood vaccines. It was therefore concluded that host factors pertaining to ethnic origin might be responsible for the hyporesponsiveness to HBV vaccine in the aboriginal populations. This finding, if substantiated with further prospective studies, might provide possible means for more targeted trials to improve vaccine response and to reduce vaccine failure among these well-defined ethnic groups.

Human skeletal muscle nebulin sequence encodes a blueprint for thin filament architecture. Sequence motifs and affinity profiles of tandem repeats and terminal SH3

Analysis of deduced protein sequence and structural motifs of approximately 5500 residues of human fetal skeletal muscle nebulin reveals the design principles of this giant multifunctional protein in the sarcomere. The bulk of the sequence is constructed of approximately 150 tandem copies of approximately 35-residue modules that can be classified into seven types. The majority of these modules form 20 super-repeats, with each super-repeat containing a 7-module set (one of each type in the same order). These super-repeats are further divided into eight segments: with six segments containing adjacent, highly homologous super-repeats, one single repeat segment consisting of 8 nebulin modules of the same type, and a non-repeat segment terminating with a SH3 domain at the C terminus. The interactions of actin, tropomyosin, troponin, and calmodulin with nebulin fragments consisting of either repeating modules or the SH3 domain support its role as a giant actin-binding cofilament of the composite thin filament. Such affinity profiles also suggest that nebulin may bind to tropomyosin and troponin to form a composite calcium-linked regulatory complex on the thin filament. The modular construction, super-repeat structure, and segmental organization of nebulin sequence appear to encode thin filament length, periodicity, insertion, and sarcomere proportion in the resting muscle.

The common I172N mutation causes conformational change of cytochrome P450c21 revealed by systematic mutation, kinetic, and structural studies

We have investigated the structure and function of P450c21 with regard to a conserved site around Ile-172 by site-directed mutagenesis making single amino acid substitutions of residues 169 173. Substitutions of Ile-171 and -172 resulted in production of mutant proteins with dramatic reductions in enzymatic activities, indicating the importance of these two residues in maintaining the structure and function of P450c21. The I171N protein was present at a slightly lower level, due to a decreased rate of protein synthesis. The I172N apoprotein was synthesized at the normal rate, but its heme-bound P450 form was present at a much lower level. This I172N protein was tightly integrated into the membrane of endoplasmic reticulum, similar to the wild type P450c21, as shown by immunofluorescence detection, alkaline extraction, and cellular fractionation. Kinetic studies indicated that I172N had a lower Vmax value. In addition, the I172N protein was more sensitive to proteinase K digestion, indicating a possible alteration of conformation. This conformational change may result in the lower yield of the I172N hemoprotein and the reduced catalytic activity.

The human aldehyde dehydrogenase 3 gene (ALDH3): identification of a new exon and diverse mRNA isoforms, and functional analysis of the promoter

Expression of the human ALDH3 gene is regulated in a tissue-dependent constitutive as well as drug-inducible manner. We identified a new 5'-noncoding exon (exon 1) existing at about 3 kilobase pairs (kb) upstream from the first coding exon (exon 2) of the human ALDH3 gene. Analysis of ALDH3 mRNA revealed the existence of several isoforms with different 5' regions resulting from i) usage of multiple transcriptional initiation sites of the new exon 1, ii) usage of alternative splice acceptor sites at the 3' end of the new intron 1, and iii) alternative splicing out of exon 2. Usage of alternative splice acceptor sites was only found in tissues expressing ALDH3 constitutively, but not in Hep G2 induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Nucleotide sequence analysis and chloramphenicol acetyltransferase (CAT) expression studies showed that a strong promoter region exists at nucleotide (nt) positions -216 to +54 of the gene. Repression activities were found upstream of the -216/+54 region. Several putative drug-inducible elements exist in the regulatory region. A possible regulatory mechanism for tissue-specific constitutive and inducible expression of the human ALDH3 gene is discussed.

The transcriptional regulation of human aldehyde dehydrogenase I gene. The structural and functional analysis of the promoter

Human cytosolic aldehyde dehydrogenase 1 (ALDH1) plays a role in the biosynthesis of retinoic acid that is a modulator for gene expression and cell differentiation. Northern blot analysis showed that liver tissue, pancreas tissue, hepatoma cells, and genital skin fibroblast cells expressed high levels of ALDH1. Sequence analysis showed that the 5'-flanking region contains a number of putative regulatory elements, such as NF-IL6, HNF-5, GATA binding sites, and putative response elements for interleukin-6, phenobarbital and androgen, in addition to a noncanonical TATA box (ATAAA) and a CCAAT box. Functional characterization of the 5'-regulatory region of the human ALDH1 gene was carried out by a fusion to the chloramphenicol acetyltransferase gene. A construct containing 2.6 kilobase pairs of the 5'-flanking region was efficiently expressed in hepatoma Hep3B cells, but not in erythroleukemic K562 cells or in fibroblast LTK- cells, which do not express ALDH1. Within this region, we define a minimal promoter (-91 to +53) that contains positive regulatory elements. The study using site-directed mutagenesis demonstrated that the CCAAT box region is the major cis-acting element involved in basal ALDH1 promoter activity in Hep3B cells. Gel mobility shift assays showed that NF-Y and other octamer factors bound CCAAT box and an octamer motif sequence, but not GATA site existing in the minimal promoter region. Two additional DNA binding activities associated with the minimal promoter were found in the nuclear extract from Hep3B cells, but not from K562 cells. These results offer the possible molecular mechanism of the cell type-specific expression of ALDH1 gene.

Comparison of high-performance liquid chromatography and capillary zone electrophoresis in penciclovir biodegradation kinetic studies

High-performance liquid chromatography (HPLC) and capillary zone electrophoresis (CZE) were used in biodegradation kinetic studies. This paper describes a rapid penciclovir separation using CZE with detection limits comparable to HPLC. The ionic-strength mediated stacking technique was employed while good resolution was maintained. With a shorter analysis time, comparable detection limits and no organic solvent consumption, CZE is a better method for penciclovir biodegradation studies than conventional reversed-phase HPLC (RP-HPLC).

New prognostic factors to predict the final outcome of brace treatment in adolescent idiopathic scoliosis

STUDY DESIGN

Eighty-five patients with adolescent idiopathic scoliosis treated with Milwaukee or thoracolumbosacral orthoses at The Duchess of Kent Children's Hospital were studied longitudinally at 4-6-month intervals until maturity for spinal curvature and vertebral rotation, or until termination of brace treatment for persons who experienced brace failure who went on to have surgery.

OBJECTIVES

To identify radiologic features so that it may be possible to predict outcome of brace treatment early on.

SUMMARY OF BACKGROUND DATA

The structural curve with poor flexibility and large rotational prominence have been found to be associated with poor prognosis for brace treatment. However, early response to bracing for spinal deformity and its relationship to final outcome of brace treatment in a longitudinal study is not available in the literature.

METHODS

Vertebral rotation and Cobb angles measured from anteroposterior radiographs of the spine obtained before bracing and 1-2 months after bracing were found valuable for prediction. Changes in post-brace Cobb angle and vertebral rotation were considered as an increase or reduction only when there was an increase or reduction of minimum 5 degrees or more from their prebrace measurements.

RESULTS

Those patients who showed increase in vertebral rotation and/or in Cobb angle after brace application were shown to have progression of curves leading to brace failure in 93% of patients, and 79% of these required surgery. The patients with no change in both vertebral rotation and Cobb angle after bracing often experienced brace failure (69%). Two patients (15%) required surgery. The results show that reduction of both Cobb angle and vertebral rotation after application of a brace is a prognostic indicator for a good outcome (97%), and no patients required surgery. Most of the patients with lumbar scoliosis (91%) showed such reductions.

CONCLUSION

The findings show a strong association between changes in vertebral rotation and the Cobb angle after application of a brace and the final outcome. Reduction in both is indicative of a good outcome, whereas increase in one or both indicates brace failure.

Cloning of a cDNA encoding human ALDH7, a new member of the aldehyde dehydrogenase family

Aldehyde dehydrogenases (ALDH; EC 1.2.1.3) are a family of isozymes which have been suggested to play a major role in the detoxification of aldehydes generated by alcohol metabolism and lipid peroxidation. Five non-allelic ALDH genes, encoding the ALDH1, 2, 3, 5 and 6 isozymes, have previously been identified and cloned in our laboratory. In this paper, we report the cloning and sequencing of a cDNA encoding a new human ALDH (ALDH7). Degenerate oligodeoxyribonucleotides derived from conserved regions of known ALDH cDNAs amplified a 408-bp product from human kidney total RNA by the reverse transcription-polymerase chain reaction (RT-PCR) procedures [Hsu et al., J. Biol. Chem. 266 (1992) 3030-3037]. This PCR product was subcloned, selected and used as a probe to screen a human kidney cDNA library. The full-length human kidney cDNA (ALDH7) is 2791 bp in length and contains an open reading frame encoding 468 amino acids (aa). The deduced sequence of ALDH7 is longer than that of the human stomach ALDH3 by 15 aa at the C terminus. The degree of identity between the two isozymes is 52% with a positional alignment of 453 aa. Northern blot analysis demonstrated that lung is another major tissue expressing ALDH7.

Molecular cloning, genomic organization, and chromosomal localization of an additional human aldehyde dehydrogenase gene, ALDH6

Aldehyde dehydrogenase isozymes have been suggested to play a major role in the detoxification of aldehydes generated by alcohol metabolism and lipid peroxidation. We previously cloned and characterized four human nonallelic ALDH genes encoding different isozymes. The existence of an unique ALDH isozyme in human saliva and its polymorphism has been demonstrated previously. In this paper, we describe the cloning, characterization, and chromosomal mapping of an aldehyde dehydrogenase gene (ALDH6) expressed in the human salivary gland. The cloned ALDH6 cDNA is 3457 bp in length and contains an open reading frame encoding 512 amino acid residues. The deduced amino acid sequence showed that ALDH6 is larger than the human liver ALDH1 by 11 amino acid residues at the N-terminal, and the degree of identity between the two isozymes is 70% with an alignment of 500 amino acid residues. The human ALDH6 gene spans about 37 kb and consists of 13 exons. The putative TATA and CCAAT boxes and Sp1 binding sites are found in the 5' upstream region of the gene. Northern blot analysis demonstrated that the ALDH6 gene is expressed at low levels in many tissues and at higher levels in salivary gland, stomach, and kidney. The ALDH6 gene was assigned to chromosome 15q26 using fluorescence in situ hybridization.

Effect of spinal fusion on growth of the spine and lower limbs in girls with adolescent idiopathic scoliosis: a longitudinal study

Two-hundred thirty-eight Southern Chinese girls, aged 10 to 14 years, treated previously for adolescent idiopathic scoliosis were studied longitudinally from the commencement of their treatment until maturity. Their standing, sitting, and suprasternal heights were measured at each follow-up visit, and their lower limb, head-neck, and spinal lengths were calculated. The results in 113 girls treated by posterior spinal fusion and Harrington instrumentation were compared with those of 125 girls who were treated with a brace. At maturity, the mean standing height of girls who underwent spinal fusion was not significantly different from that of patients treated with a brace. The fusion group had significantly shorter spinal lengths (p = 0.001), but significantly greater leg lengths (p = 0.001) compared to those of the brace group. Their arm lengths were similar, however. The girls who underwent spinal fusion had progressively increasing leg/arm ratios postoperatively from bone age 14-15 years onward compared to those treated with a brace, which indicated disproportionately longer legs in the girls who had spinal fusion. These findings suggest that spinal fusion performed on the girls with adolescent idiopathic scoliosis did retard the longitudinal growth of the spine. The standing height was unaffected, however, as the loss in spinal length was compensated by an increase in leg length.

Neutrophil dynamics and retention in lung, oxygenator, and arterial filter during cardiopulmonary bypass in a pig model

Interactions of neutrophils with adsorbed proteins in components of the cardiopulmonary bypass (CPB) circuit and expression of leukocyte adhesion molecules on activated neutrophils affect neutrophil kinetics and margination. Lung and skeletal muscle along with oxygenator (OX) and arterial filter (AF) in the extracorporeal circuit provide the major areas of neutrophil (N) interaction. The dynamics of N-interaction and N-retention during 3 hr CPB was quantified with autologous In-111 labeled neutrophils (INN) in 4 groups of 20 Yorkshire pigs (28-35 kg, 5 sham; 5 CPB, 1 hr; 5 CPB, 3 hr and 5 CPB with heparinized circuit, 3 hr); anesthetized pigs were injected with INN (500-650 microCi), 30 min before CPB and heparinized, and underwent CPB with a roller pump, a hollow fiber OX (Bentley CM 50, 5.0 m2) and AF (Bentley AF 025, 0.25 m2) at 2.5-3.6 l/min for 3 hr. N-dynamics on OX and AF was monitored by a calibrated Geiger probe. Neutrophil deposition, like that of plasma proteins on OX, reached a steady state almost instantly, but increased on filter with CPB time. INN distribution was viewed with a gamma camera; total INN was measured with an ion chamber and INN in samples of fibers and tissues was quantified with a gamma counter. INN in lung did not change significantly during CPB and increased in liver. The percentage of injected INN in lung, liver, and brain changed with CPB time and showed significant increase over sham-operated animals. Heparin coating of components decreased INN retention. INN/meter2 of lung, OX, and AF at 3 hr were 0.26 +/- 0.07%, 0.06 +/- 0.02%, and 6.17 +/- 3.94%, and significantly lower on a heparin coated filter (2.14 +/- 1.30%). Capillary surface areas of viscera and connective tissues (lung, 100; liver, 134; spleen, 20; heart, 7; skeletal muscle, 92; fat, 12; bone, 3; bone marrow, 5; brain, 0.1 meter2) were estimated from distribution of activated INN in pigs. Lung INN retention was much higher than that of the polymer surfaces of OX/AF, indicating the role of cell adhesion molecules on INN retention on endothelial cells of lung and viscera. By direct continuous monitoring and quantitation of INN at the end of CPB, a sensitive technique for quantitation of neutrophil kinetics, margination, and retention during CPB was developed.

Genetic identification of Mcs-1, a rat mammary carcinoma suppressor gene

Women have inherited differences in their susceptibility to breast cancer, but the genes underlying this variation are difficult to identify. We have approached the problem of identifying breast cancer susceptibility genes by using a rat model. Inbred rat strains display differential susceptibilities to mammary carcinogenesis; the Copenhagen (COP) rat is resistant, while the Wistar-Furth (WF) rat is susceptible to induction of mammary tumors by 7,12-dimethylbenz[a]anthracene. Genetic breeding studies have shown that tumor resistance in the COP rat is a dominant phenotype, termed the rat mammary carcinoma suppressor trait. As a step toward defining the basis of this resistance, we undertook genetic mapping of this phenotype in a (WF x COP)F1 x WF backcross by studying a large collection of microsatellite and minisatellite polymorphisms. A total of 114 genetic markers, covering approximately 75% of the rat genome, were genotyped in the backcross progeny. A marker on rat chromosome 2 was found to show linkage to the resistance phenotype. Genetic linkage was demonstrated both in a qualitative analysis (in which rats were defined as resistant if they developed 0 tumors and sensitive if they developed two or more tumors; LOD score, 4.0) and in a quantitative trait locus analysis (in which tumor number was used as the quantitative phenotype; LOD score, 3.8). We infer the existence of a gene, Mcs-1, on rat chromosome 2 that suppresses mammary carcinogenesis.

Surgical management of spinal tuberculosis in adults. Hong Kong operation compared with debridement surgery for short and long term outcome of deformity

Of 112 patients who were subjects of the Medical Research Council's prospective study, 105 (94%) were involved in a longitudinal study follow-up for a mean of 15.3 years postoperatively. Seventy-one patients had radical resection of the tuberculous lesion and bone grafting, and the remaining 34 were treated with debridement surgery at a mean age of 36.7 and 35.3 years, respectively. All these patients were aged 18 years or older at the time of surgery. The kyphosis and deformity angles were measured on lateral spinal radiographs using an electronic digitizer. The results can be summarized as follows: (1) Neurologic recovery in both radical and debridement surgical groups were equally good and no patient had pain two years after surgery. There was no incidence of reactivation or recurrence of tuberculosis in either surgical group. (2) At the six-month postoperative evaluation, patients who had radical surgery showed marginal correction in deformity, whereas those who were treated with debridement showed deterioration in both kyphosis and deformity angles. There was a statistically significant difference between the two surgical groups for the mean changes in kyphosis and deformity angles at the six-month postoperative evaluation compared with their preoperative evaluation. (3) The mean difference for kyphosis and deformity angles at final follow-up evaluation from the patients' six-month postoperative measurements were not statistically significantly different between the two surgical groups. (4) Forty percent of patients showed an improvement in deformity angle by 5 degrees or more after radical surgery at the six-months postoperative evaluation, whereas 53% of patients showed deterioration after debridement surgery. (5) All patients with tuberculosis of the lumbar spine treated with radical surgery had normal lordosis in the lumbar spine at final follow-up evaluation, compared with only 63% of patients after debridement surgery. Correction achieved after surgery at the six-month evaluation was practically maintained up to final follow-up evaluation. Radical resection and bone grafting provided better correction of deformity than did debridement surgery.

Spinal deformity after childhood surgery for tuberculosis of the spine. A comparison of radical surgery and debridement

We have reviewed 80 children who were involved in the Medical Research Council (UK) trial of surgical treatment for tuberculosis of the spine in Hong Kong. Radical surgery or debridement had been performed at mean ages of 7.6 years (n = 47) and 5.1 years (n = 33) respectively. The patients were followed up to skeletal maturity (mean 17 years). Spinal deformity was measured on lateral radiographs taken preoperatively, at six months, one year, five years and at final follow-up. Radical surgery and grafting produced a reduction in kyphos and deformity angles at six months; this correction was maintained during the growth period. By contrast, after debridement surgery there was an increase in deformity at six months, with a tendency to some spontaneous correction during the growth period. There were statistically significant differences between angles for the radical and debridement groups only at six months postoperatively, but the changes during later follow-up were similar in the radical and debridement groups. Our findings highlight the importance of the surgical correction of deformity, and provide no evidence to suggest that disproportionate posterior spinal growth contributes to progression of deformity after anterior spinal fusion in children.

Bivariate flow karyotyping, sorting, and peak assignment of all rat chromosomes

A bivariate flow cytometric rat karyotype was established from second- and third-passage Copenhagen (Cop) rat embryo cell cultures. Chromosome suspensions from such cells (2n = 42 chromosomes) yielded bivariate flow karyotypes composed of 14-18 peaks, 10 of which were sortable into pools of single chromosome types. Conditions affecting resolution of peaks (including the length of colcemid treatment of cells and various combinations of fluorescent and nonfluorescent dyes) were optimized. Using chromosome suspensions from second-passage cultures of adult Cop male and female ear fibroblasts, peaks representing the X and Y chromosomes were identified. Assignment of chromosomes was accomplished by polymerase chain reactions of flow-sorted chromosomes using primers from mapped genes. Availability of this characterized rat flow karyotype should prove useful for assignment of genes to chromosomes as well as generation of chromosome-specific libraries in cloning assigned genes.

Spinal deformity after childhood surgery for tuberculosis of the spine. A comparison of radical surgery and debridement

We have reviewed 80 children who were involved in the Medical Research Council (UK) trial of surgical treatment for tuberculosis of the spine in Hong Kong. Radical surgery or debridement had been performed at mean ages of 7.6 years (n = 47) and 5.1 years (n = 33) respectively. The patients were followed up to skeletal maturity (mean 17 years). Spinal deformity was measured on lateral radiographs taken preoperatively, at six months, one year, five years and at final follow-up. Radical surgery and grafting produced a reduction in kyphos and deformity angles at six months; this correction was maintained during the growth period. By contrast, after debridement surgery there was an increase in deformity at six months, with a tendency to some spontaneous correction during the growth period. There were statistically significant differences between angles for the radical and debridement groups only at six months postoperatively, but the changes during later follow-up were similar in the radical and debridement groups. Our findings highlight the importance of the surgical correction of deformity, and provide no evidence to suggest that disproportionate posterior spinal growth contributes to progression of deformity after anterior spinal fusion in children.

Cloning and characterization of overexpressed genes in the mammary gland of rat strains carrying the mammary carcinoma suppressor (Mcs) gene

Inbred rat strains vary in their susceptibilities to mammary carcinogenesis. The Copenhagen (COP) and Wistar-Kyoto (WKY) rats are tumor resistant, whereas the Wistar-Furth (WF), Fischer (F344), and outbred Sprague-Dawley (SD) rats are susceptible. A dominant pattern of inheritance acting via the mammary carcinoma suppressor (Mcs) gene(s), which is mainly responsible for mammary tumor resistance, has been defined in the COP and WKY rats. In order to understand the basis of the phenotype, COP and WF mammary mRNAs were used for subtractive hybridization to isolate genes associated with the activity of the Mcs gene(s). Three genes, alpha-casein, lipoprotein lipase, and an unidentified gene, were found to be overexpressed in the mammary gland of the COP rat. In addition to alpha-casein overexpression, Northern analysis demonstrated that beta- and gamma-casein genes were also highly expressed in the mammary glands of tumor-resistant WKY and COP virgin rats but not the susceptible F344, WF, and SD strains. The association of casein gene expression with the tumor-resistant phenotype was further investigated by determining the functional site of the strain-specific casein gene regulation by using a mammary cell transplantation assay. In contrast to its normal endocrine control during pregnancy and lactation, casein gene overexpression was found to be controlled within the mammary epithelial cells of virgin rats. This is also the site of production and action of the Mcs gene product. Comparison of polymerase chain reaction-amplified beta-casein precursor RNA levels with the use of reverse transcription-polymerase chain reaction revealed that the regulation of this gene is likely at the transcriptional level. These data suggest an association of overexpression of casein genes, with the Mcs phenotype. The biological significance of this association is under investigation.

Diverse polymorphism within a short coding region of the human aldehyde dehydrogenase-5 (ALDH5) gene

Human aldehyde dehydrogenase-5 gene (originally named as ALDHX) is expressed in liver and testis. The ALDH5 does not contain introns in the coding sequence for 517 amino acid residues. Within a short nucleotide region of the gene, the following three nucleotide changes were found in high frequencies, i.e., a silent C<-->T at nucleotide (nt) 183, C<-->T at nt 257 associated with a Val<-->Ala substitution, and T<-->G at nt 320 associated with a Arg<-->Leu substitution. The frequency of C at nt 183 is 81% in Caucasians and 65% in Japanese, and the difference is statistically not significant. The frequency of C at nt 257 is 76% in Caucasians and 55% in Japanese, and the difference is statistically significant (P = 0.02). The frequency of T at nt 320 is 71% in Caucasians, while it is only 27% in Japanese. The racial difference at nt 320 is highly significant (P < 0.001). No significant difference was found in the genotypes of the three nucleotide positions between alcoholic and nonalcoholic Caucasians within the limited numbers of subjects examined.

Cloning a plant amino acid transporter by functional complementation of a yeast amino acid transport mutant

Amino acids are transported across the plasma membrane of plant cells by proton-amino acid symports. We report here the successful cloning of a neutral amino acid carrier by functional complementation. A histidine transport deletion mutant of Saccharomyces cerevisiae was transformed with an Arabidopsis thaliana cDNA library constructed in a yeast expression vector. Forty transformants, out of 10(5), allowed growth on a histidine-limiting medium. The acquired ability to grow on low histidine was shown to be strictly dependent on the protein encoded by the expression plasmid. Histidine and alanine transport activity were 10- to 20-fold greater in the transformants. The transport kinetics, inhibitor sensitivity, and substrate specificity match those of neutral system II, a neutral amino acid carrier we previously described in plasma membrane vesicles isolated from leaf tissue. The cDNA insert is 1.7 kb with an open reading frame that codes for a protein containing 486 amino acids with a calculated molecular mass of 52.9 kDa and three sites of potential N-linked glycosylation. Hydropathy analysis of the deduced amino acid sequence suggests this is an integral membrane protein with 10-12 membrane-spanning alpha-helices. Overall, the sequence of this amino acid carrier is not closely related to any other protein sequences in the GenBank data base. Interestingly, however, there are small regions of sequence that exhibit significant levels of similarity with at least seven other integral membrane proteins.

The N-terminal hydrophobic domain of P450c21 is required for membrane insertion and enzyme stability

Microsomal cytochromes P-450 are known to be integrated into smooth endoplasmic reticulum through their hydrophobic sequences located at the N termini. The length requirement of the membrane insertion signal was determined by the generation of six plasmids encoding mutant P450c21 that lacked various portions of the N-terminal hydrophobic domains. When they were transcribed and translated in vitro in the presence of endoplasmic reticulum membranes, mutant protein lacking more than a third of the first hydrophobic domain gradually lost the ability to insert into the membrane and stayed mostly in the soluble fraction when the first N-terminal hydrophobic domain was removed. The steady-state amount of the truncated proteins was progressively reduced in parallel to the extent of their N-terminal deletions, due to their fast degradation. This process was accompanied by a decrease in the enzymatic activity. Therefore, the first hydrophobic domain of P450c21 not only serves as a membrane targeting and anchoring domain, but it is also important for the in vivo protein stability.

New methods of measuring vertebral rotation from computed tomographic scans. An intraobserver and interobserver study on girls with scoliosis

The purpose of this study was to search for constant and reliable reference points on the computed tomographic scans of scoliotic spines to measure vertebral rotation. Several methods using different sets of reference points on computed tomographic scans were tested for reliability. Two methods that gave minimum variation between the readings are presented here with interobserver and intraobserver reliability on 17 girls with adolescent idiopathic scoliosis. The selection of reference points for the two methods were as follows: In method 1, the vertebral rotation was an angle formed by two lines; one, a line joining the junction of the inner surfaces of two laminae and the midpoint of the posterior surface of the vertebral body and second, the vertical plane of the computed tomographic machine. In method 2, three datum points were marked; one at the junction of the inner surfaces of the laminae, and the other, one each at the junction of the inner surfaces of the lamina and the pedicle. A line bisecting this angle is drawn by the computer and the vertebral rotation was an angle between this line and the vertical plane. The 95% confidence intervals of these two methods for intraobserver variation were between 1.2 to 4.4 degrees. There was no significant difference between the readings obtained by each observer except on three occasions for observer 1. When these methods were tested for interobserver reliability, method 1 showed significant statistical differences between the readings obtained by the two observers. However, the readings obtained using method 2 were not significantly different between the two observers (95% confidence intervals = 3.2 to 5.8 degrees).(ABSTRACT TRUNCATED AT 250 WORDS)

Split tibialis posterior transfer for equinovarus deformity in cerebral palsy. Long-term results of a new surgical procedure

We report the results of a new surgical procedure for spastic equinovarus deformity due to cerebral palsy. This is the transfer of the anterior half of the split tibialis posterior to the dorsum of the foot through the interosseous membrane. We performed the operation on 23 feet in 18 children. All patients were assessed before operation and at follow-up at a mean of 8.4 years postoperatively. Using the criteria of Kling et al (1985), excellent results were obtained in 14 feet, good results in eight, and a poor result in only one.