Ankle arthrodesis: internal non-compression arthrodesis versus internal compression arthrodesis

Ankle arthrodesis is still considered to be the standard treatment for most disabling types of ankle arthritis, but fusion methods are varied. We report our experience of ankle arthrodesis and compare a group of 34 cases treated by Blair's non-compression arthrodesis to another group of 32 cases treated by internal compression arthrodesis using two crossed screws. The same surgeon performed all the operations. The Blair's non-compression arthrodesis group included 21 males and 13 females with an average age of 42 y/o (range 18-70 y/o) and an average follow up period of 38.6 months (range 26-62 months). The union rate was 91.2% and the average union time was 5.6 months (range 2-10 months). There were three cases of non-union. The cross-screw compression arthrodesis group included 20 males and 12 females with an average age of 45 y/o (range 20-86 y/o) and an average follow up period of 38.3 months (range 15-81 months). The union rate was 96.9% and the average union time was 2.7 months (range 1.5-4.4 months). There was one case of non-union. We conclude that our cross-screws compression arthrodesis with its shorter fusion time was found to be superior to the Blair's non-compression arthrodesis.

The gene locus yijP contributes to Escherichia coli K1 invasion of brain microvascular endothelial cells

Most cases of Escherichia coli meningitis develop as a result of hematogenous spread, but it is not clear how circulating E. coli crosses the blood-brain barrier. A TnphoA mutant of E. coli K1 RS218 was shown to be significantly less invasive than its parent strain in bovine and human brain microvascular endothelial cells (BMEC), which constitute the blood-brain barrier. More importantly, traversal of the blood-brain barrier was significantly less with this mutant than with the parent strain in newborn rats with experimental hematogenous meningitis. A DNA segment containing the TnphoA insertion site was cloned from RS218, and the cloned DNA complemented the TnphoA mutant in invasion of BMEC. Nucleotide sequence revealed a near identity to that of a hypothetical yijP gene (also called f577) in the E. coli K-12 genome. Sequence analysis indicated that the E. coli K1 yijP gene likely encodes a 66. 6-kDa membrane protein. Deletion and complementation experiments indicated that the yijP gene was involved in E. coli K1 invasion of BMEC, i.e., the invasive ability of E. coli K1 was significantly reduced after yijP was deleted and was restored by complementation with a plasmid containing the yijP open reading frame. This is the first demonstration that the yijP gene locus plays a role in the pathogenesis of E. coli K1 meningitis.

Combination of color Doppler ultrasonography and ultrasound-guided fine-needle aspiration cytology for localization of parathyroid lesions

We examined the usefulness of color Doppler ultrasonography combined with ultrasound-guided fine-needle aspiration cytology (FNAC) for preoperative localization of parathyroid lesions in patients with hyperparathyroidism. Twenty-eight patients (19 men, 9 women; mean age, 56 years) with clinical and laboratory evidence of hyperparathyroidism underwent preoperative color Doppler ultrasonography and ultrasound-guided FNAC prior to surgery. On ultrasonography, the parathyroid lesions were anechoic or hypoechoic, located behind or at the margin of the thyroid gland, and mimicked blood vessels in some cases. On color Doppler ultrasound, parathyroid lesions showed little or no vascularity. They were easily differentiated from blood vessels, thus improving the safety of ultrasound-guided FNAC. Thirty-four (76%) of 45 surgically confirmed parathyroid lesions were detected with ultrasonography in 21 (75%) of the patients. There was no significant difference in the detection rates of lesions in the right upper, right lower, left upper, and left lower parathyroid glands. Eight (29%) patients had coexisting thyroid lesions. FNAC of the ultrasound-detected abnormalities provided preoperative confirmation that they were parathyroid lesions. In conclusion, our findings show that color Doppler ultrasonogrphy in combination with ultrasound-guided FNAC is useful for preoperative localization of parathyroid lesions.

Identification and characterization of an Escherichia coli invasion gene locus, ibeB, required for penetration of brain microvascular endothelial cells

Escherichia coli K1 is the most common gram-negative organism causing neonatal meningitis, but the mechanism by which E. coli K1 crosses the blood-brain barrier is incompletely understood. We have previously described the cloning and molecular characterization of a determinant, ibeA (also called ibe10), from the chromosome of an invasive cerebrospinal fluid isolate of E. coli K1 strain RS218 (O18:K1:H7). Here we report the identification of another chromosomal locus, ibeB, which allows RS218 to invade brain microvascular endothelial cells (BMEC). The noninvasive TnphoA mutant 7A-33 exhibited <1% the invasive ability of the parent strain in vitro in BMEC and was significantly less invasive in the central nervous system in the newborn rat model of hematogenous E. coli meningitis than the parent strain. The TnphoA insert with flanking sequences was cloned and sequenced. A 1,383-nucleotide open reading frame (ORF) encoding a 50-kDa protein was identified and termed ibeB. This ORF was found to be 97% identical to a gene encoding a 50-kDa hypothetical protein (p77211) and located in the 13-min region of the E. coli K-12 genome. However, no homology was observed between ibeB and other known invasion genes when DNA and protein databases in GenBank were searched. Like the TnphoA insertion mutant 7A-33, an isogenic ibeB deletion mutant (IB7D5) was unable to invade BMEC. A 7. 0-kb locus containing ibeB was isolated from a LambdaGEM-12 genomic library of E. coli RS218 and subcloned into a pBluescript KS vector (pKS7-7B). pKS7-7B was capable of completely restoring the BMEC invasion of the noninvasive TnphoA mutant 7A-33 and the ibeB deletion mutant IB7D5 to the level of the parent strain. More importantly, the ibeB deletion mutant IB7D5 was fully complemented by pFN476 carrying the ibeB ORF (pFN7C), indicating that ibeB is required for E. coli K1 invasion of BMEC. Taken together, these findings indicate that several E. coli determinants, including ibeA and ibeB, contribute to crossing of the blood-brain barrier.

Sagittal craniosynostosis outcome assessment for two methods and timings of intervention

A retrospective quantitative analysis of 40 infants who underwent surgery for sagittal craniosynostosis was conducted to determine whether any difference in outcome, with respect to cranial index (cranial width/cranial length x 100), could be associated with either the age at surgery or the extent of the operation. Children < or = 13 months old at surgery and for whom there were archived computed tomography digital data preoperatively, perioperatively, and 1 year postoperatively were studied. For statistical analysis, the operation was classified as either extended strip craniectomy or subtotal calvarectomy, and the age at operation was either < or = 4 months or > 4 months. Twenty-eight patients underwent extended strip craniectomy at a mean age of 5.1 months. Their mean cranial index preoperatively was 67 versus 71 at 1 year postoperatively (p < 0.0001). Of extended strip craniectomy patients, 15 were operated on at age < or = 4 months (mean = 2.9 months) and 13 at age > 4 months (mean = 7.6 months). Mean cranial indices for age at operation groups did not achieve age-appropriate normal range values 1 year postoperatively for either group, and there was no significant difference between the mean percentages of improvement achieved (p = 0.143). Twelve patients underwent subtotal calvarectomy at a mean age of 5.2 months. Their mean cranial index preoperatively was 66 versus 74 at 1 year postoperatively (p < 0.0001). The mean cranial index in this group reached age-appropriate normal range values 1 year postoperatively. The percentage improvement in cranial index 1 year after subtotal calvarectomy was greater than after extended strip craniectomy (p = 0.003). Extended strip craniectomy for sagittal craniosynostosis does not achieve normal cranial width:length proportions, even when performed before 4 months of age. Subtotal calvarectomy for sagittal craniosynostosis does achieve normal cranial width:length proportions in the majority of the children, at least when performed within the first 13 months of life.

The essential role of Saccharomyces cerevisiae CDC6 nucleotide-binding site in cell growth, DNA synthesis, and Orc1 association

Saccharomyces cerevisiae Cdc6 is a protein required for the initiation of DNA replication. The biochemical function of the protein is unknown, but the primary sequence contains motifs characteristic of nucleotide-binding sites. To study the requirement of the nucleotide-binding site for the essential function of Cdc6, we have changed the conserved Lys114 at the nucleotide-binding site to five other amino acid residues. We have used these mutants to investigate in vivo roles of the conserved lysine in the growth rate of transformant cells and the complementation of cdc6 temperature-sensitive mutant cells. Our results suggest that replacement of Lys with Glu (K114E) and Pro (K114P) leads to loss-of-function in supporting cell growth, replacement of the Lys with Gln (K114Q) or Leu (K114L) yields partially functional proteins, and replacement with Arg yields a phenotype equivalent to wild-type, a silent mutation. To investigate what leads to the growth defects derived from the mutations at the nucleotide-binding site, we evaluated its gene functions in DNA replication by the assays of the plasmid stability and chromosomal DNA synthesis. Indeed, the K114P and K114E mutants showed the complete retraction of DNA synthesis. In order to test its effect on the G1/S transition of the cell cycle, we have carried out the temporal and spatial studies of yeast replication complex. To do this, yeast chromatin fractions from synchronized culture were prepared to detect the Mcm5 loading onto the chromatin in the presence of the wild-type Cdc6 or mutant cdc6(K114E) proteins. We found that cdc6(K114E) is defective in the association with chromatin and in the loading of Mcm5 onto chromatin origins. To further investigate the molecular mechanism of nucleotide-binding function, we have demonstrated that the Cdc6 protein associates with Orc1 in vitro and in vivo. Intriguingly, the interaction between Orc1 and Cdc6 is disrupted when the cdc6(K114E) protein is used. Our results suggest that a proper molecular interaction between Orc1 and Cdc6 depends on the functional ATP-binding of Cdc6, which may be a prerequisite step to assemble the operational replicative complex at the G1/S transition.

Comparison of invasive and noninvasive tests for detecting Helicobacter pylori infection in bleeding peptic ulcers

BACKGROUND

Eradication of Helicobacter pylori infection has been shown to prevent recurrent bleeding from peptic ulcers. However, the detection rate for H pylori infection seems to be underestimated in this group of patients and has been scarcely investigated.

METHODS

Eighty patients with bleeding peptic ulcer were studied for evidence of H pylori infection. Seventy-seven of these patients were enrolled as having H pylori infection after any one of the following 3 tests were positive: culture, histologic study, or any 2 of rapid urease test (CLO test), carbon 13-labeled urea breath test (UBT), and serologic examination. Fresh blood or blood-containing material in the gastric antrum was noted by panendoscopy in 22 patients (group A). In the remaining 55 cases there was no blood in the antrum (group B).

RESULTS

The sensitivities of the CLO test, bacterial culture, histologic study, 13C-labeled UBT, and immunoglobulin G serologic test were 45.5%, 36.4%, 77.2%, 95.4%, and 100% in group A, respectively, and 70.9%, 40.0%, 70.9%, 92.7%, and 96.4%, respectively, in group B. There was a statistically significant difference between the sensitivities found for CLO test and 13C-labeled UBT (p < 0.05). Of these 5 tests, only the sensitivity of the CLO test showed a statistically significant difference between groups A and B (p < 0.05). A delayed positive CLO test result was recorded in 13 patients (3 in group A, 10 in group B).

CONCLUSION

Noninvasive tests seemed to be more sensitive than invasive tests in detecting H pylori infection in patients with bleeding peptic ulcers. Blood in the antrum might reduce the sensitivity of the CLO test but have no effect on the other tests. The CLO test should be observed for more than 24 hours because of the possibility of a delayed positive result in some patients with bleeding peptic ulcers.

Identification and characterization of a novel Ibe10 binding protein that contributes to Escherichia coli invasion of brain microvascular endothelial cells

The molecular basis of Escherichia coli traversal of the blood-brain barrier in the development of E. coli meningitis is not well understood. We have previously shown that a novel Ibe10 protein found in cerebrospinal fluid isolates of E. coli is necessary for invasion of the brain microvascular endothelial cells (BMEC) that constitute the blood-brain barrier both in vitro and in a newborn rat model of hematogenous meningitis. Here we identified a novel Ibe10 binding molecule/receptor (Ibe10R) on both bovine BMEC (HBMEC) and human BMEC (HBMEC) that is responsible for invasion by E. coli. Ibe10R, an approximately 55-kDa protein, was purified from BBMEC by Ibe10-Ni-Sepharose affinity chromatography. Bovine Ibe10R, as well as polyclonal antibodies to Ibe10R, blocked E. coli invasion of BBMEC very effectively. The N-terminal amino acid sequence of Ibe10R showed 75% homology to serum albumin. However, the amino acid sequence of an Ibe10R fragment generated by limited enzymatic digestion did not reveal homology to any other proteins, suggesting that Ibe10R represents a novel albumin-like protein. Immunocytochemical analysis of BBMEC using anti-Ibe10R antibody suggested that only a subset of cultured BBMEC express Ibe10R on their surface. Enrichment of Ibe10R-positive BBMEC by fluorescence-activated cell sorting with anti-Ibe10R antibody resulted in enhanced invasion by E. coli. The anti-Ibe10R antibody raised against bovine Ibe10R also blocked E. coli invasion of HBMEC very effectively. Interestingly, anti-Ibe10R antibody affinity chromatography of HBMEC membrane proteins revealed a smaller protein with an approximate molecular mass of 45 kDa. These results suggest that the Ibe10 of E. coli interacts with a novel BMEC surface protein, Ibe10R, for invasion of both BBMEC and HBMEC.

A case of extraadrenal pheochromocytoma associated with adrenal cortical nodular hyperplasia and papillary thyroid carcinoma

A 64-year-old woman was admitted in November, 1996 for fluctuating blood pressure. There was multinodular goiter in her neck. High urine VMA and serum aldosterone were noted. Computed tomography showed an oval lesion in the left adrenal gland. Left adrenalectomy was performed and the pathology was proved to be adrenal cortical nodular hyperplasia. Fluctuating blood pressure and high urine VMA persisted after the operation. CT scan of the abdomen revealed a soft tissue mass in lower abdomen. The patient was admitted again in September, 1997. Laboratory examinations showed normal serum aldosterone, normal plasma renin activity and high urine VMA. Aspiration cytology of the thyroid gland disclosed papillary thyroid carcinoma. [131I]-metaiodobenzylguanidine image revealed a high uptake lesion in the right L-3 paravertebral area. Tumor excision and thyroidectomy were performed. The pathology was reported as extraadrenal pheochromocytoma and papillary thyroid carcinoma. Papillary thyroid carcinoma is rarely associated with pheochromocytoma. To our knowledge, this paper is the first report of a patient with extraadrenal pheochromocytoma associated with papillary thyroid carcinoma and adrenal cortical nodular hyperplasia.

Intraosseous schwannoma of the fourth lumbar vertebra: case report

OBJECTIVE AND IMPORTANCE

Intraosseous schwannomas (neurilemomas) are rare neoplasms. In one large series, schwannomas accounted for less than 0.2% of all primary bone tumors. These schwannomas most commonly arise in the mandible and have also been observed, very rarely, in the vertebra. We present a patient with an unusual intraosseous schwannoma in the lumbar vertebra.

CLINICAL PRESENTATION

A 58-year-old man who was admitted to Cathay General Hospital had complained of numbness and pain in his lower extremities for approximately 1 year. At the time of admission, a neurological examination revealed mild motor weakness and sensory numbness bilaterally in his lower legs. Magnetic resonance images showed a neoplastic lesion occupying the entire L4 body and the superior part of the L5 body, with marked perivertebral protrusion and compression of the thecal sac and bilateral neuroforamina.

INTERVENTION

The patient underwent a computed tomography-guided needle biopsy and a two-stage operation. During the initial surgical procedure, the tumor mass was totally removed via an anterolateral approach. Fixation and fusion of the third to fifth lumbar vertebral bodies was accomplished using a full-thickness iliac bone graft with an anterior locking plate and screws. During the second operation, posterior fusion of L2, L3, L4, L5, and S1 with Luque wires and a Hartshill rectangle rod was performed to increase the spinal stability.

CONCLUSION

Intraosseous schwannomas are rare neoplasms that are not commonly observed in the lumbar vertebral bodies. Schwannomas in the lumbar spine commonly originate from the nerve passing through the neural foramina. We report a rare case of L4 intraosseous schwannoma, the magnetic resonance imaging, computed tomographic, and histological findings, and the surgical procedures.

One-week low-dose triple therapy is effective in treating Helicobacter pylori-infected patients with bleeding peptic ulcers

Proton pump inhibitor (PPI)-based triple therapy, which combines a PPI and two antibiotics, is highly effective in eradicating Helicobacter pylori infection in peptic ulcer patients, even if given for only 1 week. However, the application of this regimen in patients with bleeding ulcers has not been adequately investigated. We studied the effectiveness of triple therapy in treating 122 patients with proven H. pylori infection, and bleeding stigmata on endoscopy; 97 had duodenal ulcer (DU), 15 had gastric ulcer (GU), and 10 had both types of ulcers. A regimen of omeprazole (20 mg), metronidazole (500 mg), and clarithromycin (250 mg) twice daily was administered for 1 week as soon as the patient could eat normally after bleeding, followed by omeprazole (20 mg) daily for 3 additional weeks. Follow-up endoscopy and 13C-urea breath tests (UBTs) were performed at least 4 weeks after triple therapy. A total of 104 patients completed the study, 83 with DU, 12 with GU, and nine with both. The overall ulcer healing rate was 97.1% and the eradication rate was 91.3%. Patients with and without H. pylori eradication did not differ significantly in terms of age, gender, UBT titer, units of blood transfused, or interval between endoscopy and the beginning of triple therapy. We conclude that 1-week low-dose PPI-based triple therapy is effective in eradicating H. pylori infection in patients with bleeding peptic ulcers. When followed by 3 weeks of additional PPI treatment, a satisfactory ulcer healing rate can also be achieved.

Preoperative localization procedures for initial surgery in primary hyperparathyroidism

The experience of the surgeon and precise localization of abnormal parathyroid glands determine the success of surgery for primary hyperparathyroidism (HPT). In HPT patients undergoing repeat surgery, the use of localization studies improved the ability to identify the remaining abnormal parathyroid tissue. This study investigated the roles of preoperative localization techniques for initial surgery for primary HPT. From 1985 through 1997, two noninvasive localization procedures, ultrasonography (US) and 201thallium chloride-99mtechnetium pertechnetate subtraction scanning (Tl-Tc), were used prior to initial exploration for primary HPT in 76 patients. Their accuracy was determined on the basis of surgical and pathologic results. The surgical success rate was 96% (73/76). The sensitivities of US and Tl-Tc were 71% and 49%, respectively. The sensitivity of Tl-Tc was higher for the lower parathyroid glands. In 21 of 26 patients who underwent fine-needle aspiration (FNA) of the suspected enlarged parathyroid gland, the diagnosis of parathyroid adenoma was confirmed preoperatively. We conclude that the concomitant use of US and FNA is a safe and convenient method for preoperative localization of the parathyroid glands prior to initial surgical exploration in patients with primary HPT. Bilateral neck exploration by an experienced surgeon should be the routine procedure. US and Tl-Tc alone offer limited localization information, and unilateral exploration should be reserved for selected cases in which the results of these two imaging studies are consistent with one another.

Distribution of the cadherin-catenin complex in normal human thyroid epithelium and a thyroid carcinoma cell line

E-cadherin is the major cell-cell adhesion molecule expressed by epithelial cells. Cadherins form a complex with three cytoplasmic proteins, alpha-, beta-, and gamma-catenin, and the interaction between them is crucial for anchoring the actin cytoskeleton to the intercellular adherens junctions. The invasive behavior of cancer cells has been attributed to a dysfunction of these molecules. In this study, we examined the distribution of the cadherin-catenin complex in a Chinese human thyroid cancer cell line, CGTH W-2, compared with that in normal human thyroid epithelial cells. In the normal cells, using immunofluorescence staining, E-cadherin and alpha-, beta-, and gammm-catenin were found to be localized at the intercellular junction and appeared as 135, 102, 90, and 80 kD proteins on Western blots. In CGTH W-2 cells, no E-cadherin and gamma-catenin immunoreactivity was detected by immunofluorescence or Western blotting; alpha- and beta-catenin were detected as 102 and 90 kD proteins on blots but gave a diffuse cytoplasmic immunofluorescence staining pattern in most cells, while beta-catenin was also distributed throughout the cytoplasm in most cells but was found at the cell junction in some, where it colocalized with alpha-actinin. The present data indicate that the loss of cell adhesiveness in these cancer cells may be due to incomplete assembly of the cadherin-catenin complex at the cell junction. However, this defect did not affect the linkage of actin bundles to vinculin-enriched intercellular junctions.

The effect of intravitreal injection of atropine on the proliferation of scleral chondrocyte in vivo

Atropine was found to be effective in arresting the progression of myopia. However, the actual mechanism is still unclear. Thus, we tried to investigate the in vivo effect of atropine on the proliferation of scleral chondrocytes in chicks of form-deprivation myopia. Twenty chicks were equally divided into 4 groups which included intravitreal injection of normal saline (IVN), IVN with goggling (IVNG), intravitreal injection of atropine (1%) (IVA), and IVA with goggling (IVAG) groups. Intravenous injection of bromodeoxyuridine (BrdU) (30 mg/kg) from subaxillary vein was performed 2 hours before being sacrificed. The eyeballs were then fixed in 10% neutral-buffered formalin at 4 degrees C. Standard BrdU immunohistochemical staining was performed. The BrdU labeling index was obtained from the average of positive labelings of BrdU in scleral chondrocytes for every 100 counting cells in posterior poles and anterior scleral margins by two experienced technicians. The BrdU index on the anterior scleral margin of the IVAG group was less than that of the IVNG group. The index on the anterior scleral margin of the IVNG group was higher than the IVN group. Although the index on the posterior poles of the IVNG group was also higher than the IVN group, it was statistically not different. Also, no statistical difference was found between IVN and IVA on the anterior scleral margins or posterior poles. The index was significantly different on the anterior scleral margins, but not on the posterior pole among each group. Therefore, intravitreal injection of atropine could inhibit the proliferation of chondrocytes on the anterior margins of sclera, but not the posterior poles in form-deprivation myopia.

RET protooncogene mutations in patients with apparently sporadic medullary thyroid carcinoma

We examined RET protooncogene mutations in sporadic medullary thyroid carcinoma (MTC), using polymerase chain reaction (PCR)-based sequencing. DNA was extracted from tumor tissue and peripheral blood leukocytes of seven unrelated individuals with apparently sporadic MTC. Oligonucleotide primers were selected to amplify exons 10, 11, 13, 15, and 16 of the RET protooncogene, to examine the sequences of codons 609, 611, 618, and 620 of exon 10, codon 634 of exon 11, codon 768 of exon 13, codon 883 of exon 15, and codon 918 of exon 16. Direct DNA sequencing from PCR products was then performed. The results showed that one patient had a somatic mutation at codon 918 (ATG-->ACG), causing a Met-->Thr substitution. One patient had a de novo germline mutation at codon 634 (TGC-->CGC), causing a Cys-->Arg substitution. Another patient had a germline mutation at codon 634 (TGC-->TTC), causing a Cys-->Phe substitution. In the remaining four cases, no RET mutations were found. Unexpectedly, two offspring of the patient (a female) with a germline mutation at codon 634 (TGC-->TTC) harbored homozygous alleles for the mutation; because the father did not carry this mutation, the other affected allele was suspected to have resulted from a de novo germline mutation of paternal origin. One of these offspring was subsequently diagnosed as having MTC. Our findings suggest that all patients with apparently sporadic MTC should be screened for the RET protooncogene by molecular analysis to detect occult or de novo multiple endocrine neoplasia 2 (MEN 2) or familial MTC. This would allow early treatment of affected family members.

Effects of cyclophosphamide on maturation and subsequent fertilizing capacity of pig oocytes in vitro

This study examines the effects of cyclophosphamide, a widely used anti-cancer agent, on the maturation of pig oocytes and on their subsequent fertilizing capacity in vitro. Pig cumulus-oocyte complexes collected from prepubertal gilts were cultured in Waymouth MB 752/1 medium supplemented with sodium pyruvate (50 micrograms/ml), luteinizing hormone (0.5 microgram/ml), follicle-stimulating hormone (0.5 microgram/ml), and 17 beta-estradiol (1 microgram/ml) in the presence or absence of cyclophosphamide for 24 hr; they then were cultured without hormonal supplements in the presence or absence of cyclophosphamide for an additional 16-24 hr. The breakdown of germinal vesicle (GVBD) and changes in glutathione (GSH) content before in vitro fertilization were assessed. Oocytes containing one polar body and a metaphase plate were regarded as matured. Cytoplasmic maturation as determined by male pronuclear formation following fertilization in vitro was also examined. Treatment of oocytes with increasing concentrations (1-1000 micrograms/ml) of cyclophosphamide for 48 hr resulted in a dose-response inhibition of the rate of maturation, but had no effect on GVBD. Increasing duration (12-48 hr) of treatment with cyclophosphamide (100 micrograms/ml) led to a time-dependent inhibition of nuclear maturation, achieving statistical significance by 24 hr. The addition of cyclophosphamide (100 micrograms/ml) to maturation medium immediately after culture, 12 hr or 24 hr after culture also decreased the percentage of oocytes matured during a 48-h culture period. Exposure of oocytes to cyclophosphamide (100 micrograms/ml) for 40 hr did not prevent sperm penetration, not affect the incidence of polyspermy, or decrease the ability of oocytes to form a male pronucleus at 8 hr after insemination. The concentration of GSH, an important factor for male pronuclear formation, in pig oocytes was determined by an enzymatic cycling assay. The concentration found was 8.15 +/- 1.19 mM per oocyte. Exposure of oocytes to cyclophosphamide (100 micrograms/ml) had no effect on GSH concentration. These results demonstrate that cyclophosphamide directly inhibits the meiotic but not cytoplasmic maturation of pig oocytes in vitro. This inhibitory effect, apparently, is not mediated through a decrease in the level of intracellular glutathione.

The effects of particle charge on the performance of a filtering facepiece

This study quantitatively determined the effect of electrostatic charge on the performance of an electret filtering facepiece. Monodisperse challenge corn oil aerosols with uniform charges were generated using a modified vibrating orifice monodisperse aerosol generator. The aerosol size distributions and concentrations upstream and downstream of an electret filter were measured using an aerodynamic particle sizer, an Aerosizer, and a scanning mobility particle sizer. The aerosol charge was measured by using an aerosol electrometer. The tested electret filter had a packing density of about 0.08, fiber size of 3 microns, and thickness of 0.75 mm. As expected, the primary filtration mechanisms for the micrometer-sized particles are interception and impaction, especially at high face velocities, while electrostatic attraction and diffusion are the filtration mechanisms for submicrometer-sized aerosol particles. The fiber charge density was estimated to be 1.35 x 10(-5) coulomb per square meter. After treatment with isopropanol, most of fiber charges were removed, causing the 0.3-micron aerosol penetration to increase from 36 to 68%. The air resistance of the filter increased slightly after immersion in the isopropanol, probably due to the coating of impurities in isopropanol. The aerosol penetration decreased with increasing aerosol charge. The most penetrating aerosol size became larger as the aerosol charge increased, e.g., from 0.32 to 1.3 microns when the aerosol charge increased from 0 to 500 elementary charges.

Antioxidant activity of lazaroid (U-75412E) and its protective effects against crystalline silica-induced cytotoxicity

Lazaroids (21-amino steroids) are believed to be powerful scavengers of reactive oxygen species (ROS) and inhibitors of lipid peroxidation. Crystalline silica, a potent cytotoxic agent, causes pulmonary fibrosis in experimental animals and humans. ROS have been previously shown to be involved in crystalline silica-induced pulmonary injury and inflammation. In the present study, the reaction rate of lazaroid (U-75412E) with hydroxyl radical (.OH) generated by Fenton reaction (Fe(II) + H2O2 --> Fe(III) + OH- + .OH) was investigated using ESR spin-trapping competition reactions. The reaction rate constant was found to be 1.0 x 10(10) M(-1)s(-1), which was comparable with those of other efficient .OH radical scavengers. As indicators of crystalline silica-induced cytotoxicity and its protection by this antioxidant lazaroid (U-75412E) we measured lactate dehydrogenase, N-acetyl-beta-glucosaminidase, superoxide dismutase, glutathione peroxidase, and hydrogen peroxide released from rat alveolar macrophages. Lipid peroxidation, a prominent manifestation of .OH radical-induced cell injury, was also measured to evaluate the protective value of lazaroid. Alveolar macrophages treated with lazaroid (U-75412E) before crystalline silica exposure were protected against cell injury and lipid peroxidation as demonstrated by those indicators. Lazaroid (U-75412E) scavenges .OH radicals generated by crystalline silica-mediated reaction from H2O2 and inhibits lipid peroxidation in macrophages induced by these particles.

Serum HDL level at acute stage of Kawasaki disease

Kawasaki disease is a disease of acute vascular inflammation of unknown etiology and HDL is a known risk factor of vascular damage. So far, there is no specific serum marker for KD. The previous study has shown a remarkable change of serum HDL in the patients with KD. To find whether changes in serum HDL level is a specific serum marker for early diagnosis of KD, we measured the concentration of HDL, LDL, TC, TG and CRP immediately after admission and one week later in three groups of patients (56 patients with KD, 38 patients with clinical viral infection, and 42 patients with bacterial infection). There was a significant decrease of HDL and increase of TG immediately after admission in three groups of patients. HDL and TG did not return to normal one week later. HDL level is more adversely affected in severe diseases than in mild diseases. Our results indicated that low HDL level is noted in various acute infection and is not a specific serum marker in the early stage of Kawasaki disease. It is interesting that low HDL is a universal phenomenon in this series. Further research is needed to explain the mechanism of lipid alterations and its consequences.

A modified immuno-polymerase chain reaction for the detection of beta-glucuronidase from Escherichia coli

A modified immuno-polymerase chain reaction (immuno-PCR) for the detection of E. coli beta-glucuronidase (GUD) is described. Flexible polycarbonate microtiter plates (Biozyme, Landgraaf) with 96 V-bottomed wells were used throughout all steps including the antigen-antibody reaction and polymerase chain reaction. The plates were coated with anti-GUD antibodies to capture the antigen, which was then detected using biotinylated anti-GUD antibodies. Following this, avidin was used to bridge the biotinylated antibodies and biotinylated lamda phage DNA, which was amplified by PCR to produce a product of 500 nucleotides. Following optimization, the detection limit of the immuno-PCR for GUD was 1 x 10(-17) g/ml (or 5 x 10(-19) g/well); this is equivalent to two GUD molecules in a sample solution of 50 microliters. The method was used to detect GUD in a cell extract of E. coli, and it was found that the enzyme released from a single E. coli cell in a solution of 10 l could be detected. So far, this is the most sensitive method ever published for the detection of an antigen. In addition to high sensitivity, the present protocol is capable of automation.

Gemfibrozil treatment of hypertriglyceridemia: improvement on fibrinolysis without change of insulin resistance

The fibrinolytic and metabolic changes associated with gemfibrozil treatment of hypertriglyceridemia were evaluated in 16 patients with type IV hyperlipidemia by criteria of triglyceride levels > 250 mg/dl and total cholesterol levels < 220 mg/dl. The plasma triglyceride level was significantly lower (323 +/- 71 vs 189 +/- 57 mg/dl; p = 0.000) and high-density lipoprotein cholesterol level significantly higher (33.5 +/- 4.6 vs 38.0 +/- 6.7 mg/dl; p = 0.005) after 3 to 4 months of gemfibrozil treatment. However, the glucose and insulin metabolism measured by oral glucose challenge and insulin suppression tests showed no significant changes after gemfibrozil therapy. In contrast, plasma plasminogen activator inhibitor-1 antigen (36.9 +/- 12.4 vs 27.3 +/- 11.4 ng/ml; p = 0.008) and activity (15.5 +/- 5.5 vs 11.8 +/- 3.0 IU/ml; p = 0.009) and tissue plasminogen activator antigen (13.2 +/- 4.0 vs 10.4 +/- 3.7 ng/ml; p = 0.007) were significantly depressed, and tissue plasimogen activator activity (0.57 +/- 0.31 vs 0.69 +/- 0.38 IU/ml; p = 0.015) was significantly elevated by gemfibrozil. The data indicate that lowering plasma triglyceride and raising high-density lipoprotein cholesterol levels by gemfibrozil treatment also improved the fibrinolytic system without changes of insulin resistance and glucose intolerance in patients with isolated hypertriglyceridemia.

Autopsy findings on patients with AIDS in Taiwan

At National Taiwan University Hospital, from 1986 to 1996, autopsies were performed on 16 patients with acquired immunodeficiency syndrome. There were 15 men and 1 woman. Fourteen of these male patients had contracted the disease as a result of sexual practice, among which 9 were homosexual, 1 was bisexual and 4 were heterosexual. One of the patients had become infected by sharing a syringe during intravenous drug use. The female was a sex worker. Among these patients, only 2 had been tested for HIV before developing AIDS. On autopsy, lymphoid depletion and thymus atrophy were found in all patients. Testicular atrophy was noted in all the male patients. Three patients died of malignant lymphoma. Twelve patients died of opportunistic infections and 1 committed suicide. The initial opportunistic infection was usually oral candidiasis. Pneumocystis carinii pneumonia (PCP) was the most common opportunistic infection developed in the early stage while cytomegalovirus (CMV) infection was the most common one found in the late stage. Mycobacterium infection had developed in 8 patients. Six patients had disseminated Kaposi's sarcoma (KS) and 4 of them were homosexual. In 4 patients, biopsy specimens were proved to have KS associated viral (HHV-8) genome. Malignant lymphoma was found in 4 cases, all were of high grade B cell type. Epstein-Barr virus (EBV) encoding small RNA (EBER1) was demonstrated in all the lymphomas. In conclusion, (1) the prevalence of tuberculosis (38%) in patients with AIDS in Taiwan is high; (2) the most common opportunistic infections in this series are candidiasis, PCP and CMV infections; (3) the incidence of AIDS related non-Hodgkin's lymphoma in Taiwan has increased since 1995.

High efficiency DNA delivery into swine oocytes and embryos by electronic pulse delivery (EPD)

The production of transgenic swine for xenotransplantation has been proposed as an optimal option to overcome the chronic shortage of human organ donors. Generation of genetically engineered swine has been elusive due to the difficulties in gene transfer. In order to achieve effective gene delivery, a key step for the genetic modification, we applied electronic pulse delivery (EPD) technology to introduce H2Kb-DC DNA construct into swine eggs. Using the developed EPD Protocols, we have achieved good viability of the EPD treated oocytes, satisfactory embryonic development of the EPD treated embryos, and stable DNA transfer into the swine embryos with high efficiency. Thus, application of the EPD technology promises to effectively facilitate the generation of large transgenic mammals.

The regulation of the scleral growth associated with deprivation myopia in chicks

The mechanism of axial elongation caused by experimental or clinical myopia is still unknown. We sought to explore the changes of scleral chondrocytes during myopia formation through the cell biology model. White Leghorn chicks were used for this study. The right eye was covered with a translucent goggle after hatching, and the left eye was left uncovered for control. The chicks were maintained on 12 hours light-dark cycle for two weeks, then sacrificed every other day and the eyeballs removed for study. Our results in the primary culture of scleral chondrocytes showed that the densities of chondrocytes on myopic eyes were significantly higher than those of the controlled non-myopic eyes, and 3H-thymidine incorporation rate also increased with the increasing of the concentration of fetal bovine serum. The PCNA index of chondrocytes in myopic eyes was also higher than that of the controlled non-myopic eyes. Thus, axial elongation of experimental myopia in the chick is the result of active tissue remodeling rather than passive scleral stretching alone.