Spinocerebellar ataxia type 2 in seven Korean families: CAG trinucleotide expansion and clinical characteristics

Studies on spinocerebellar ataxias (SCA) have been hampered by a lack of disease markers. Clinical and pathological heterogeneity also made the classification unreliable. Linkage studies established that there are multiple subtypes of SCA. Five types are found to have unstable CAG expansion; the diagnosis can be established by molecular genetic study. Therefore, we systemically screened degenerative ataxia patients for these five SCA types, and identified eight patients with SCA2 (seven from six families and one sporadic case). This paper presents the clinical information on the seven patients, whose clinical information was available in detail. CAG repeat expansion in the patients ranged from 38 to 47 (normal control, 19 to 27). The onset ages ranged from 16 to 41 with 27.1 years as the mean, which correlated inversely with repeat lengths. All patients presented dysarthria and gait ataxia. Upper limb dysmetria or dysdiadochokinesia appeared later but progressed, causing severe disability. Slow saccade (4 patients in 7) and decreased DTR (4 in 7) were common. MRIs showed severe atrophy of the brainstem and cerebellum in all patients. We conclude that SCA2 is the most frequent type in Korea and carries rather pure cerebellar syndrome, slow saccade, and hyporeflexia.

Correction of genu recurvatum by the Ilizarov method

The Ilizarov apparatus was used to carry out opening-wedge callotasis of the proximal tibia in ten patients who had suffered premature asymmetrical closure of the proximal tibial physis and subsequent genu recurvatum. In four knees, the genu recurvatum was entirely due to osseous deformity, whereas in six it was associated with capsuloligamentous abnormality. Preoperatively, the angle of recurvatum averaged 19.6 degrees (15 to 26), the angle of tilt of the tibial plateau, 76.6 degrees (62 to 90), and the ipsilateral limb shortening, 2.7 cm (0.5 to 8.7). The average time for correction was 49 days (23 to 85). The average duration of external fixation was 150 days (88 to 210). Three patients suffered complications including patella infera, pin-track infection and transient peroneal nerve palsy. At a mean follow-up of 4.4 years, all patients, except one, had achieved an excellent or good radiological and functional outcome.

Cyclin D1 overexpression is an indicator of poor prognosis in resectable non-small cell lung cancer

Cyclin D1 is one of the G1 cyclins that control cell cycle progression by allowing G1 to S transition. Overexpression of cyclin D1 has been postulated to play an important role in the development of human cancers. We have investigated the correlation between cyclin D1 overexpression and known clinicopathological factors and also its prognostic implication on resected non-small-cell lung cancer (NSCLC) patients. Formalin-fixed and paraffin-embedded tumour tissues resected from 69 NSCLC patients between stages I and IIIa were immunohistochemically examined to detect altered cyclin D1 expression. Twenty-four cases (34.8%) revealed positive immunoreactivity for cyclin D1. Cyclin D1 overexpression is significantly higher in patients with lymph node metastasis (50.0% vs 14.4%, P = 0.002) and with advanced pathological stages (I, 10%; II, 53.8%; IIIa, 41.7%, P = 0.048; stage I vs II, IIIa, P = 0.006). Twenty-four patients with cyclin D1-positive immunoreactivity revealed a significantly shorter overall survival than the patients with negativity (24.0 +/- 3.9 months vs 50.1 +/- 6.4 months, P = 0.0299). Among 33 patients between stages I and II, nine patients with cyclin D1-positive immunoreactivity had a much shorter overall survival (29.7 +/- 6.1 months vs 74.6 +/- 8.6 months, P = 0.0066). These results suggest that cyclin D1 overexpression is involved in tumorigenesis of NSCLCs from early stage and could be a predictive molecular marker for poor prognosis in resectable NSCLC patients, which may help us to choose proper therapeutic modalities after resection of the tumor.

Intravitreal dexamethasone effect on intravitreal vancomycin elimination in endophthalmitis

OBJECTIVE

To determine whether intravitreal dexamethasone administration can alter the elimination of intravitreal vancomycin hydrochloride in rabbit eyes with experimental Streptococcus pneumoniae endophthalmitis.

METHODS

Albino rabbits were infected with an intravitreal inoculum of S pneumoniae (2 x 10(3) colony-forming units) and randomized after 24 hours to treatment with intravitreal vancomycin hydrochloride (1 mg), alone or in combination with intravitreal dexamethasone (400 microg). For comparison, uninfected eyes were similarly treated. All eyes were enucleated 24, 48, or 72 hours after treatment, and vitreous levels of vancomycin were quantitated using a fluorescence polarizing immunoassay.

RESULTS

The half-life of intravitreal vancomycin in infected eyes was prolonged from 48 to 84 hours when eyes were treated with dexamethasone. Conversely, such treatment shortened the half-life in uninfected eyes from 56 to 42 hours.

CONCLUSIONS

Intravitreal dexamethasone administration reduces the elimination of intravitreal vancomycin in rabbit eyes with pneumococcal endophthalmitis, whereas an opposite effect is noted in uninfected eyes.

CLINICAL RELEVANCE

In patients with eyes having endophthalmitis caused by virulent organisms, the elimination of intravitreal vancomycin may be reduced when intraocular inflammation is minimized with corticosteroid therapy. This may enhance the efficacy of intravitreal vancomycin therapy in treating the infection.

Powered instrumentation for rhinoplasty and septoplasty

Advances in surgical instrumentation are generally intended to allow the performance of a surgical maneuver more efficiently and accurately. Powered instrumentation may allow improved precision and ease in certain aspects of rhinoplasty and septoplasty. Through improved precision, tissue trauma can be minimized.

Protective effect of chlormethiazole, a sedative, against acetaminophen-induced liver injury in mice

OBJECTIVES

The hepatotoxicity of acetaminophen is not a result of the parent compound but is mediated by its reactive metabolite N-acetyl-p-benzoquinone imine. Cytochrome P4502E1 (CYP2E1) is the principal enzyme of this biotransformation, which accounts for approximately 52% of the bioactivation in human microsomes. Recently, chlormethiazole a sedative drug, is reported to be an efficient inhibitor of CYP2E1 activity in human beings. In this study we wished to evaluate whether chlormethiazole, an inhibitor of CYP2E1, could prevent acetaminophen-induced liver injury in mice.

METHODS

Acetaminophen, at doses ranging from 200 to 600 mg/kg, was injected into the peritoneum of female C57BL/6 inbred mice fasted for four hours. Chlormethiazole (60 mg/kg) or 5% dextrose water was given 30 min before or 2 h after acetaminophen. Serum aminotransferase activities, histologic index score, survival rate and hepatic malondialdehyde levels were compared.

RESULTS

Pretreatment with chlormethiazole 30 min before 400 mg/kg of acetaminophen completely inhibited acetaminophen-induced liver injury (median 118.5 U/L, range 75 to 142 vs. 14,070 U/L, range 5980 to 27,680 for AST; 49 U/L, range 41 to 64 vs. 15,330 U/L, range 13,920 to 15,940 for ALT). In mice receiving chlormethiazole 2 h after acetaminophen, the mean AST and ALT levels were also less elevated, reaching only 20% of the value of acetaminophen-only group. These protective effects were confirmed histologically. Whereas more than 50% of mice died at 500 mg/kg of acetaminophen, all the mice pretreated with chlormethiazole survived at the same dose.

CONCLUSION

Chlormethiazole effectively reduces acetaminophen-induced liver injury in mice. Further studies are needed to assess its role in humans.

A 3-year multi-institutional experience with the liposhaver

OBJECTIVE

To report a 3-year multi-institutional clinical experience with the liposhaver in facial plastic surgery.

DESIGN

Nonrandomized, nonblinded, multi-institutional evaluation of the liposhaver in a clinical setting.

INTERVENTIONS

Seventy-two patients who presented for facial plastic surgical procedures underwent surgery with the liposhaver. Seventy-six liposhaving procedures and 74 concomitant procedures were performed. Standardized preoperative and postoperative photographs were obtained.

OUTCOME MEASURE

Subjective evaluation by the surgeons who performed the procedures.

RESULTS

The liposhaver was used successfully in all cases. The fat was cleanly shaved and the contour results were even, without dimpling or significant asymmetry. Operative time was comparable to that of conventional liposuction. There were no cases of facial nerve injury and no evidence of increased bleeding intraoperatively. Two male patients had small postoperative hematomas in the immediate postoperative period that were successfully treated with conservative measures. An additional patient developed a small hematoma on postoperative day 5 that was effectively treated with needle aspiration and a pressure dressing.

CONCLUSION

This 3-year multi-institutional report suggests that the liposhaver continues to offer a precise alternative to conventional liposuction.

Combined effects of ethanol and garlic on hepatic ethanol metabolism in mice

The combined effects of ethanol and components in fresh garlic on ethanol metabolism were investigated in the livers of mice. Male, 11-wk-old C3H/HeNCrj mice were intragastrically administered 2 g ethanol/kg body weight after being administered fresh garlic juice for 8 d (garlic group), and changes in the concentrations of ethanol, acetaldehyde and acetate in the serum, and changes in the activity of hepatic enzymes related to ethanol metabolism in mice were examined. The increases in the concentrations of acetaldehyde and acetate in the serum after ethanol administration tended to be diminished following garlic administration. The microsomal ethanol-oxidizing system (MEOS) in the livers of the garlic groups was significantly lower than that of the control microsomes at 2 h after ethanol administration. It therefore seems that the decrease of MEOS in hepatic microsomes caused a smaller increase in the acetaldehyde concentration in the serum of the garlic groups because cytosolic alcohol dehydrogenase showed no significant difference between the control and garlic groups. After ethanol administration, the content of cytochrome P-450 in the hepatic microsomes of the control groups increased, while that of the garlic groups did not change although cytochrome P-450 (CYP) 2E1 and 1A2 in the hepatic microsomes of the garlic groups increased. These results indicate that the induction of isozymes of cytochrome P-450 other than CYP 2E1 and 1A2 was inhibited following garlic administration. Cytosolic high Km and total aldehyde dehydrogenase (AIDH) in the liver of the garlic groups tended to be lower than those activities of the control groups at 1 and 2 h after ethanol administration. It therefore seems that the decreases of AIDH in the hepatic cytosols diminished the increase of acetate in the serum of the garlic groups after ethanol administration. These results suggest that the ethanol metabolism in the mouse liver is controlled by components in fresh garlic juice.

Expression of differentiation markers during fetal skin development in humans: immunohistochemical studies on the precursor proteins forming the cornified cell envelope

The cornified cell envelope is formed during the terminal differentiation of epidermis through cross-linking of specific proteins by transglutaminases. The specific arrangement of individual protein in the cornified cell envelope and participation of individual protein in the cornified cell envelope at different regions of skin, i.e., palm, foreskin, lips, etc. are not clearly understood. In order to understand the pattern and expression schedule of each individual precursor protein during the differentiation and formation of cornified cell envelope, the expression of precursor proteins in developing human fetal skins from the first to the third trimester were examined by immunohistochemical studies. Involucrin was found in the periderm and intermediate layer from 14 wk estimated gestational age, while loricrin and small proline-rich protein 1 were found in the periderm from 16 wk estimated gestational age. Filaggrin and trichohyalin that are absent in the adult cornified cell envelope were found in the granular and horny layers from 24 wk estimated gestational age. The precursor proteins except trichohyalin did not change their patterns after the onset of initial expression during development. Trichohyalin was transiently expressed in the granular and horny layers of the epidermis from 24 wk estimated gestational age with peak expression at 27 wk estimated gestational age, but was not detected in adult skin. In hair follicles, trichohyalin expression was stable without change from 20 wk estimated gestational age. These findings suggest that fetal skin may have different sets of barriers from the second trimester; the immature cornified cell envelope is formed in the early second trimester and the mature cornified cell envelope is formed in the late second or early third trimester when filaggrin and trichohyalin appear.

Vesicular ATPase-overexpressing cells determine the distribution of malaria parasite oocysts on the midguts of mosquitoes

In Plasmodium-infected mosquitoes, oocysts are preferentially located at the posterior half of the posterior midgut. Because mosquitoes rest vertically after feeding, the effect of gravity on the ingested blood has been proposed as the cause of such a biased distribution. In this paper, we examined the oocyst distribution on the midguts of mosquitoes that were continuously rotated to nullify the effect of gravity and found that the typical pattern of oocyst distribution did not change. Invasion of the midgut epithelium by ookinetes was similarly found to be biased toward the posterior part of the posterior midgut. We examined whether the distribution of oocysts depends on the distribution of vesicular ATPase (V-ATPase)-overexpressing cells that Plasmodium ookinetes preferentially use to cross the midgut epithelium. An antiserum raised against recombinant Aedes aegypti V-ATPase B subunit indicated that the majority of V-ATPase-overexpressing cells in Ae. aegypti and Anopheles gambiae are localized at the posterior part of the posterior midgut. We propose that the typical distribution of oocysts on the mosquito midgut is attributable to the presence and the spatial distribution of the V-ATPase-overexpressing cells in the midgut epithelium.

Differential expression of mouse Disabled 2 gene in retinoic acid-treated F9 embryonal carcinoma cells and early mouse embryos

Using a differential display PCR, we identified a differentially expressed cDNA fragment which was detectable in retinoic acid (RA) treated F9 embryonal carcinoma (EC) cells but not in untreated F9 cells. A homology search of the Gene Bank indicated that the cDNA fragment is part of the mouse homolog of the Drosophila Disabled (mDab2) gene. Aggregate cultures of F9 EC cells grown in the presence of the RA differentiated into nonmalignant cells resembling the visceral endoderm of the mouse embryo. Upon induction of endodermal differentiation with 10(-7) M RA, the gene expression of mDab2 was increased gradually during the first 96 h. Neither undifferentiated F9 cells, nor the undifferentiated aggregate cells without RA expressed mDab2. Whole-mount in situ hybridization and quantitative RT-PCR also showed that the temporal expression pattern of the mDab2 gene coincides with the initiation pattern of RA synthesis that occurs during mouse embryogenesis. Also, two alternative splicing messages of mDab2 were detected in a tissue specific manner. All the data indicate that mDab2 may play an important role in RA-induced signal transduction during mouse development.

Clinical application of the M-numbers of aortic cannulas during hypothermic cardiopulmonary bypass in pediatric patients

A standardized system to describe the pressure-flow characteristics of a given cannula has recently been proposed and has been termed the M-number system. Using 3 different sizes of aortic cannulas in 50 pediatric cardiac patients on hypothermic cardiopulmonary bypass, we analyzed the correlation between experimentally and clinically derived M-numbers and found it to be positive. Clinical M-numbers were typically 0.35 to 0.55 greater than experimental M-numbers and correlated inversely with a patient's temperature change; this was most probably due to increased blood viscosity arising from hypothermia. This inverse relationship was more marked in higher M-number cannulas. The clinical data obtained in this study suggest that the experimentally derived M-number correlates strongly with the clinical performance of the cannula and that the influence of temperature is significant.

Surgery for the dysfunctional nasal valve. Cadaveric analysis and clinical outcomes

OBJECTIVES

To quantify changes in the cross-sectional area of the nasal valve after placement of spreader grafts and flaring sutures and to review clinical outcomes after nasal valve surgery.

DESIGN

The minimal cross-sectional area of cadaveric nasal valves was measured after placement of spreader grafts and flaring sutures. Clinical outcomes for patients undergoing functional rhinoplasty were retrospectively reviewed.

SETTING

Academic medical center.

SUBJECTS

Six fresh cadaver heads and a review of patients from September 1994 through May 1998.

INTERVENTION

Acoustic rhinometry was performed after placement of spreader grafts, flaring sutures, and the two together. Clinically, a site-specific repair was performed with spreader grafts and flaring sutures for statically narrowed internal nasal valves and cartilaginous battens for dynamic collapse.

MAIN OUTCOME MEASURE

Cross-sectional areas of cadaveric valves. Functional and aesthetic results were determined by nasal patency scores from 1 (complete obstruction) to 10 (complete patency) and a rating of postsurgical cosmetic changes.

RESULTS

Spreader grafts improved the cadaveric minimal cross-sectional areas by 5.4% (P > .05), flaring sutures by 9.1% (P > .05), and spreader grafts combined with flaring sutures by 18.7% (P < .05). Mean nasal patency scores improved from 3.4 to 6.5 (P < .01) with the combination of spreader grafts and flaring sutures. Cartilaginous battens improved scores from 2.7 to 6.3 (P < .01).

CONCLUSIONS

The combination of flaring sutures and spreader grafts has the greatest impact on the cadaveric nasal airway. Either technique alone failed to have a statistically significant impact on the minimal cross-sectional area of the nasal valve. Clinical review confirms significant improvement in nasal function using this combination technique.

Functional nasal surgery

Functional nasal surgery is designed to repair nasal obstruction frequently caused by previous reduction rhinoplasty or blunt nasal trauma. Distinguishing the statically narrowed nasal valve from the weak sidewall with dynamic collapse is an important part of the preoperative evaluation. Our workhorse for repair of static obstruction is the combination of spreader grafts and flaring sutures, which together create a significant increase in the intranasal valve area. Dynamic collapse of the sidewall is corrected with cartilaginous batten grafts designed to increase sidewall rigidity. Less common causes of valve obstruction, such as tip ptosis, facial paralysis, cicatricial stenosis, Mohs reconstruction, and paradoxical lateral crura, are repaired by more individualized techniques.

A novel Bacillus subtilis gene, antE, temporally regulated and convergent to and overlapping dnaE

A Bacillus subtilis promoter, Px, that functions in a convergent manner with the sigA operon promoter P3 has been found in the sigA operon. Promoter Px is turned on at the same time as promoter P3 during early sporulation. The transcript from promoter Px codes for a small protein with partial homology to the OmpR protein from Escherichia coli and also carries an untranslated sequence at its 3' end that is complementary to the 5' end of the P3 transcript, which codes for the ribosome binding site of dnaE. The gene controlled by Px has been called antE. The expression of antE does not require sigmaB, sigmaE, or sigmaH. Px was transcribed in vitro by the sigmaA holoenzyme and is the seventh promoter to be recognized in the sigmaA operon. A possible role for the antE gene during early sporulation is proposed.

Isolation and characterization of immune-related genes from the fall webworm, Hyphantria cunea, using PCR-based differential display and subtractive cloning

Following injection of bacteria into the hemocoel of the fall webworm, Hyphantria cunea, several inducible genes were identified and characterized using PCR-based differential display (DD-PCR) and subtractive cloning. Ten immune-related cDNA clones (Hdd1, Hdd2, Hdd3, Hdd11, Hdd13, Hdd15, Hdd17, Hdd23, Hs106, Hs302) were isolated and characterized. The deduced amino acid sequence of Hdd2 was shown to be a member of the copper, zinc superoxide dismutase (Cu-Zn SOD) family. The H. cunea Cu-Zn SOD is novel in that it is up-regulated following a bacterial challenge and has a putative signal peptide suggesting its secretion and involvement in the insect immune response. Hdd3 was found to encode a new member of the serpin (serine protease inhibitor) family. The putative lectin corresponding to Hdd15 is of a different kind in that it has two lectin C domains in a single molecule. These two lectin C domains show significant homology to the lectin C domain of Periplaneta lipopolysaccharide binding protein (LPS-BP). Three cloned genes, Hdd17, Hs106 and Hs302, encode a homologue to Bombyx mori Gram negative binding protein, a hemolin-like protein and a attacin-like protein, respectively. The deduced amino acid sequences from Hdd11 showed weak homology with a Locusta migratoria hemolymph protein. On the contrary, Hdd1, Hdd13 and Hdd23 did not reveal any significant homology with known proteins. All of the 10 genes were clearly inducible by E. coli and M. luteus injection. Injection of distilled water only slightly induced mRNA levels. Comparison of temporal mRNA expression following E. coli injection showed three types of expression patterns.

Prevalence of specific antibodies to Chlamydia pneumoniae in Korea

To clarify the endemic status of Chlamydia pneumoniae in Korea, the incidence of antibodies in 564 serum samples from healthy individuals, patients with respiratory infection, and cord blood specimens was evaluated. We conclude that C. pneumoniae infection is highly endemic in Korea and that this infection is associated with acute respiratory diseases.

Two-step autocatalytic processing of the glutaryl 7-aminocephalosporanic acid acylase from Pseudomonas sp. strain GK16

The glutaryl-7-aminocephalosporanic acid (GL-7-ACA) acylase of Pseudomonas sp. strain GK16 is an (alphabeta)2 heterotetramer of two nonidentical subunits. These subunits are derived from nascent polypeptides that are cleaved proteolytically between Gly198 and Ser199 after the nascent polypeptides have been translocated into the periplasm. The activation mechanism of the GL-7-ACA acylase has been analyzed by both in vivo and in vitro expression studies, site-directed mutagenesis, in vitro renaturation of inactive enzyme precursors, and enzyme reconstitution. An active enzyme complex was found in the cytoplasm when its translocation into the periplasm was suppressed. In addition, the in vitro-expressed GL-7-ACA acylase was processed into alpha and beta subunits, and the inactive enzyme aggregate of the precursor was also processed and became active during the renaturation step. Mutation of Ser199 to Cys199 and enzyme reconstitution allowed us to identify the secondary processing site that resides in the alpha subunit and to show that Ser199 of the beta subunit is essential for these two sequential processing steps. Mass spectrometry clearly indicated that the secondary processing occurs at Gly189-Asp190. All of the data suggest that the enzyme is activated through a two-step autocatalytic process upon folding: the first step is an intramolecular cleavage of the precursor between Gly198 and Ser199 for generation of the alpha subunit, containing the spacer peptide, and the beta subunit; the second is an intermolecular event, which is catalyzed by the N-terminal Ser (Ser199) of the beta subunit and results in a further cleavage and the removal of the spacer peptide (Asp190 to Gly198).

Hyperbaric oxygen for the management of radionecrosis of bone and cartilage

OBJECTIVES

To review the use of hyperbaric oxygen in the management of radionecrosis of the head and neck.

STUDY DESIGN

A retrospective analysis of patients utilizing chart review and telephone interviews. All patients diagnosed with osteoradionecrosis and chondroradionecrosis of the head and neck and treated with hyperbaric oxygen at the University of Virginia are included.

METHODS

Demographics, pretreatment data, and precipitating events were recorded. Outcomes were evaluated using a grading scale of symptomatology and physical examination as determined by the patient and physician.

RESULTS

Sixteen patients with osteoradionecrosis and five with chondroradionecrosis were reviewed. All patients showed clinical improvement with decreased pain following HBO therapy. None of the patients with chondroradionecrosis required laryngectomies, and two of the four who were tracheotomy dependent were successfully decannulated. The patient and physician grading scores demonstrated moderate to significant improvement in both groups following therapy.

CONCLUSION

The successful use of hyperbaric oxygen for the management of radionecrosis of the head and neck is supported. The unusual prevalence of chondroradionecrosis may be an early reflection of changes in treatment protocols for patients with head and neck cancer.

Effects of motorcycle exhaust on cytochrome P-450-dependent monooxygenases and glutathione S-transferase in rat tissues

The effects of motorcycle exhaust (ME) on cytochrome P-450 (P-450)-dependent monooxygenases were determined using rats exposed to the exhaust by either inhalation, intratracheal, or intraperitoneal administration. A 4-wk ME inhalation significantly increased benzo[a]pyrene hydroxylation, 7-ethoxyresorufin O-deethylation, and NADPH-cytochrome c reductase activities in liver, kidney, and lung microsomes. Intratracheal instillation of organic extracts of ME particulate (MEP) caused a dose- and time-dependent significant increase of monooxygenase activity. Intratracheal treatment with 0.1 g MEP extract/kg markedly elevated benzo[a]pyrene hydroxylation and 7-ethoxyresorufin O-deethylation activities in the rat tissues 24 h following treatment. Intraperitoneal treatment with 0.5 g MEP extract/kg/d for 4 d resulted in significant increases of P-450 and cytochrome b5 contents and NADPH-cytochrome c reductase activity in liver microsomes. The intraperitoneal treatment also markedly increased monooxygenases activities toward methoxyresorufin, aniline, benzphetamine, and erythromycin in liver and benzo[a]pyrene and 7-ethoxyresorufin in liver, kidney, and lung. Immunoblotting analyses of microsomal proteins using a mouse monoclonal antibody (Mab) 1-12-3 against rat P-450 1A1 revealed that ME inhalation, MEP intratracheal, or MEP intraperitoneal treatment increased a P-450 1A protein in the hepatic and extrahepatic tissues. Protein blots analyzed using antibodies to P-450 enzymes showed that MEP intraperitoneal treatment caused increases of P-450 2B, 2E, and 3A subfamily proteins in the liver. The ME inhalation, MEP intratracheal, or MEP intraperitoneal treatment resulted in significant increases in glutathione S-transferase activity in liver cytosols. The present study shows that ME and MEP extract contain substances that can induce multiple forms of P-450 and glutathione S-transferase activity in the rat.

A second form of phenylalanine ammonia-lyase from leaf mustard

Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) catalyzes the elimination of ammonium ion from L-phenylalanine in a variety of plants and fungal species. PAL was previously purified and characterized from leaf mustard in our laboratory. In the present study, we purified a second phenylalanine ammonia-lyase (PAL II) from leaf mustard by a combination of ion exchange chromatography and gel filtration. PAL I and PAL II migrate at a different rate on native polyacrylamide gel electrophoresis. It consists of four subunits, each having the molecular mass of about 37,000 Da. Its isoelectric point and Km value for L-phenylalanine were found to be 5.4 and 3.8 x 10(-5)M, respectively. The purified enzyme has an optimum pH and temperature of 8 and 45 degree C, respectively. It is activated about 2-fold by caffeic acid (1 mM), whereas it is inhibited to 15% by Zn2+ (1 mM). However, the physiological role of PAL II remains unknown.

Gene frequencies of eight human platelet-specific antigens in Koreans

Human platelet-specific antigens (HPAs) are found on platelet membrane glycoproteins and are the target of platelet alloantibodies that mediate platelet destruction in neonatal alloimmune thrombocytopenia (NAIT), post-transfusion purpura (PTP) and refractoriness to platelet transfusion therapy. The biallelic polymorphism of all HPA systems is known to be due to a substitution of a single base pair. This study was performed to investigate the frequency of the HPA genes in Koreans, based on these substitutions. The genotypes of eight HPA systems were determined by polymerase chain reaction using sequence-specific primers (PCR-SSP) for HPA-1, -2, -4, -5, and -8 and restriction fragment length polymorphism (RFLP) for HPA-3, -6, and -7. The gene frequencies obtained from 200 unrelated Koreans were 0.99 and 0.01 for HPA-1a and -1b, 0.92 and 0.08 for HPA-2a and -2b, 0.55 and 0.45 for HPA-3a and -3b, 0.99 and 0.01 for HPA-4a and -4b, 0.98 and 0.02 for HPA-5a and -5b, and 0.98 and 0.02 for HPA-6a and -6b. All the individuals tested were homozygotes for HPA-7a and HPA-8a. It has been reported that the HPA-1b antigen is extremely rare (less than 0.3%) in Oriental populations, but this study suggests that the frequency of this antigen in Koreans (2.0%) is higher than in Japanese and Chinese populations.

Autogenous tissue-engineered cartilage: evaluation as an implant material

OBJECTIVES

To determine whether autogenous tissue-engineered cartilage grafts can be synthesized in predetermined shapes, to compare tissue-engineered cartilage with native cartilage with respect to histological characteristics and biomechanical properties, and to demonstrate how multiple transplantations affect tissue-engineered cartilage.

DESIGN

Controlled, prospective animal study.

SUBJECTS

Twenty New Zealand white rabbits, 3 weeks old.

INTERVENTIONS

Autogenous chondrocytes were seeded onto biodegradable polyglycolic acid-poly-L-lactic acid copolymer templates in 1 of 3 shapes (cross, nasal tip graft, or auricle). Grafts and controls of sculpted cartilage were divided among 3 groups: short-term implantation (4 or 8 weeks), long-term implantation (6 or 12 months), and a reimplantation group. The gross morphological features, histological findings, and tensile strength of grafts were assessed.

RESULTS

Production of tissue-engineered cartilage was confirmed in 30 of 31 implants. Histological evaluation demonstrated characteristic cartilaginous matrix, but with prominent vascular and fibrous tissue ingrowth. In long-term implantation grafts (n=4), foci of osteoid were evident by 6 months. In the subset of transplanted grafts (n=7), 5 of 7 demonstrated significant loss of cartilage viability. Tensile strength measurements demonstrated values 24% and 41% of those of controls at 4 and 8 weeks, respectively.

CONCLUSIONS

Tissue-engineered autogenous cartilage can be reliably produced, and predetermination of graft shape is possible. Histologically, grafts represent composites of mature cartilage infiltrated by vasculature and fibrous tissue, with delayed osteoid formation. Graft viability is compromised by early transplantation, and tensile strength is less than that of native cartilage. These results demonstrate the feasibility of tissue-engineered cartilage as a future graft material.