Facial nerve repair and regeneration: an overview of basic principles for neurosurgeons

The facial nerve may be damaged by trauma, surgical manipulation, inflammation or neoplastic disease. Current techniques for repair and regeneration of the damaged nerve produce suboptimal results. This review outlines the current knowledge of experimental facial nerve regeneration in vitro and in vivo to provide an insight for neurosurgeons in clinical practice.

Expansins: ever-expanding numbers and functions

Expansins were first identified as cell-wall-loosening proteins that, at least in part, mediate pH-dependent extension of the plant cell wall and growth of the cell. More recently, it has been realized that expansins belong to two protein families, the alpha-and beta-expansins, and that they appear to be involved in regulating, besides cell expansion, a variety of plant processes, including morphogenesis, softening of fruits, and growth of the pollen tube of grasses through the stigma and the style. The Arabidopsis genome contains 26 alpha-expansin genes and the rice genome at least 26. There are more beta-expansin genes in monocots than in dicots, at least 14 in rice and five in Arabidopsis. Expansin genes are differentially regulated by environmental and hormonal signals, and hormonal regulatory elements have been found in their promoter regions. An analysis of exon/intron structure led to the hypothesis that alpha-and beta-expansins evolved from a common ancestral gene.

Hepatocellular carcinoma treated with percutaneous radio-frequency ablation: evaluation with follow-up multiphase helical CT

PURPOSE

To determine serial changes in hepatocellular carcinomas (HCCs) treated with percutaneous radio-frequency (RF) ablation at long-term follow-up multiphase helical computed tomography (CT).

MATERIALS AND METHODS

There were 43 nodular HCCs in 40 patients at follow-up CT performed not less than 12 months after RF ablation. All patients underwent follow-up multiphase helical CT immediately, 1 month, and then every 3 months after percutaneous RF ablation. The serial changes in attenuation, enhancement pattern, shape, other findings, and volume of the ablated lesions were analyzed at follow-up CT.

RESULTS

Thirty-eight (88%) of 43 ablated lesions were of low attenuation, with absence of contrast material enhancement at immediate and 1-month follow-up CT, which is suggestive of successful treatment. The remaining five lesions (12%) showed peripheral nodular enhancement, suggesting residual viable tumor. Compared with volume changes at immediate follow-up CT, the mean percentages of volume change at 1, 4, 10, 16, and 19 months were 79%, 50%, 27%, 11%, and 6%, respectively. Of 43 ablated lesions, 24 (56%) were mostly round at immediate CT and remained unchanged at subsequent follow-up CT. Peripheral rim enhancement was seen in 34 (79%) of 43 lesions at immediate CT but resolved in all 34 lesions at 1-month follow-up CT. Other associated findings included iatrogenic arteriovenous shunt in 10 patients, perihepatic hemorrhage in three, and pneumothorax in one.

CONCLUSION

Follow-up multiphase helical CT of HCCs treated with percutaneous RF ablation showed variable findings in the treated lesions and surrounding liver parenchyma.

Conspicuity of hepatocellular nodular lesions in cirrhotic livers at ferumoxides-enhanced MR imaging: importance of Kupffer cell number

PURPOSE

To correlate the conspicuity of hepatocellular carcinomas and dysplastic nodules on ferumoxides-enhanced magnetic resonance (MR) images with the number of Kupffer cells in the hepatic lesions, as compared with that in background liver in histopathologic findings.

MATERIALS AND METHODS

Sixty-nine histopathologically proved moderately or poorly differentiated hepatocellular carcinomas, 10 well-differentiated hepatocellular carcinomas, and 19 dysplastic nodules were retrospectively studied in 68 patients with cirrhosis who underwent ferumoxides-enhanced MR imaging. The contrast-to-noise ratio between the nodules and surrounding parenchyma was calculated at T2-weighted fast spin-echo imaging, and the difference in the number of Kupffer cells between the nodules and surrounding hepatic tissue was calculated histopathologically. The results of MR imaging and histopathologic examination were correlated.

RESULTS

All 69 moderately or poorly differentiated hepatocellular carcinomas had high contrast-to-noise ratios at MR imaging and large differences in the number of Kupffer cells. Six of the 10 well-differentiated hepatocellular carcinomas had contrast-to-noise ratios of zero or nearly zero, and five of these had little difference in the number of Kupffer cells. All 19 dysplastic nodules had contrast-to-noise ratios of zero or nearly zero, and there were virtually no differences in the number of Kupffer cells.

CONCLUSION

Hepatocellular nodule conspicuity at ferumoxides-enhanced MR imaging depends on differences in the number of Kupffer cells within a nodule and the surrounding cirrhotic liver; moderately or poorly differentiated hepatocellular carcinomas can be distinguished from well-differentiated hepatocellular carcinomas and dysplastic nodules.

Detection of hepatocellular carcinoma: combined T2-weighted and dynamic gadolinium-enhanced MRI versus combined CT during arterial portography and CT hepatic arteriography

PURPOSE

The purpose of this study was to compare the preoperative detectability of hepatocellular carcinomas (HCCs) using combined T2-weighted and dynamic gadolinium-enhanced MRI and combined CT during arterial portography (CTAP) and CT hepatic arteriography (CTHA).

METHOD

Thirty-three patients with 43 HCCs underwent T2-weighted and dynamic gadolinium-enhanced MRI and combined CTAP and CTHA. The diagnosis was established by pathologic examination following surgical resection in 26 patients and by biopsy in 7 patients. The MR protocol included fast SE with two TEs (including T2-weighted imaging) and precontrast and gadolinium-enhanced T1-weighted fast multiplanar spoiled gradient-recalled echo images with dynamic study. The MR images of all sequences and the paired CTAP and CTHA images were independently reviewed by three radiologists. Image review was conducted on a segment-by-segment basis. Diagnostic accuracy was evaluated with receiver operating characteristic analysis.

RESULTS

The accuracies (Az values) of MRI of all sequences and combined CTAP and CTHA for all observers were 0.960 and 0.959, respectively. The mean sensitivities of MRI and CT were 90 and 94%, respectively. The differences were not statistically significant. The mean specificity of MRI (99%) was significantly higher than that of combined CTAP and CTHA (92%).

CONCLUSION

Combined T2-weighted and dynamic gadolinium-enhanced MRI is as accurate as combined CTAP and CTHA for preoperative detection of HCCs.

Molecular cloning of a novel pathogen-inducible cDNA encoding a putative acyl-CoA synthetase from Capsicum annuum L

By means of differential display, a pool of salicylic acid (SA)-induced mRNAs were identified and subsequently their cDNAs were isolated from a cDNA library prepared from SA-induced leaf tissues of hot pepper. One of these cDNA clones, designated CaSIG4, was 1900 bp and contained an open reading frame encoding 523 amino acids with a calculated molecular mass of 56.3 kDa. The predicted amino acid sequence of CaSIG4 showed high sequence similarity to the AMP-binding protein family of both prokaryotic and eukaryotic acyl-CoA synthetases. CaSIG4 transcripts accumulated rapidly after SA treatment and in response to both incompatible and compatible interactions with Xanthomonas campestris pv. vesicatoria race 1. To investigate the cis-acting elements mediating CaSIG4 expression, the CaSIG4 5'-flanking region was isolated by inverse PCR. Database searches indicated that a potential cis-regulatory element is almost identical to the consensus core sequences ACC(A/T)ACC(A/C) which are conserved among promoters of other phenylpropanoid biosynthetic genes. The subcellular localization of the CaSIG4 protein was studied by using a soluble modified GFP gene fusion delivered into epidermal cells of onion by biolistic bombardment. The CaSIG4-smGFP fusion protein was localized to the plasma membrane. Taken together, CaSIG4 encoding a putative acyl-CoA synthetase could function as a plasma membrane-bound protein with a role in signaling in plant defense.

Postinfarction left ventricular rupture misdiagnosed ruptured intramural hematoma of aorta

Left ventricular rupture is a fatal complication of acute myocardial infarction, however accurate preoperative diagnosis is still difficult. We experienced a postinfarction left ventricular rupture patient whose symptoms and radiologic findings mimicked those of acute intramural hematoma of the aorta. Upon emergency operation, he was proven to have a postinfarction LV rupture and underwent successful surgery. We herein report the case with a brief review of the literature.

Aortic dissection: percutaneous management with a separating stent-graft--preliminary results

The authors used a separating stent-graft to treat Stanford type B aortic dissection. The separating stent-graft consists of two stents: a stent-graft and an inner bare stent. The separating stent-graft has three parts: a proximal stent, a graft made of synthetic polyester textile fiber, and a distal stent. A 12-F introducing sheath was used. After the separating stent-graft was placed, false-lumen thrombosis was evident in all six patients during a follow-up period of 206 days. The major advantages of this technique are that a cutdown and blood pressure control are not required.

Hepatocellular carcinoma: correlation between vascular endothelial growth factor level and degree of enhancement by multiphase contrast-enhanced computed tomography

RATIONALE AND OBJECTIVES

To determine whether vascular endothelial growth factor (VEGF) is a histopathological factor influencing contrast enhancement of hepatocellular carcinoma (HCC) on computed tomography (CT).

METHODS

Twenty-two nodular HCCs underwent multiphase helical CT and surgery. Tumor size, histological grading of differentiation, and type of hepatitis were evaluated. Tumor attenuation was graded as hyperattenuated, isoattenuated, and hypoattenuated. Immunohistochemical staining with anti-VEGF antibody was performed and scored as weak, intermediate, or strong. Spearman's rank correlation test was used.

RESULTS

Tumors ranged from 1.0 to 12.0 cm (mean 5.1 cm). The degree of enhancement during the hepatic arterial phase was significantly correlated with VEGF expression. Size was negatively correlated with VEGF expression and the degree of enhancement, but histological grade and type of hepatitis were not correlated with VEGF expression, tumor size, or degree of enhancement.

CONCLUSIONS

In HCC, VEGF expression is correlated with the degree of contrast enhancement during arterial-phase CT.

Effectiveness of surveillance of central catheter-related bloodstream infection in an ICU in Korea

OBJECTIVE

To determine whether surveillance and infection control interventions decrease the incidence of catheter-related (CR) bloodstream infections (BSIs) in Korea.

SETTING

A medical-surgical intensive care unit (ICU) of a university hospital in Korea.

DESIGN

The CR infection rate of the intervention period was compared to that of historical controls for a 4-month period.

PATIENTS

All patients with a central venous catheter in the intensive care unit (ICU) from October 1998 to January 1999.

METHODS

Active infection control programs were initiated during the intervention period. Data collected included patient characteristics, risk factors of CR infection, and the microbiology laboratory results. Laboratory-proven CR infection rates were compared between the intervention group and control group.

RESULTS

304 catheters were inserted into 248 patients. The intervention group and the control group showed similar characteristics, but more patients in the intervention group received steroid therapy, and subclavian insertion was more common in the intervention group. CR BSI occurred in 1.3 per 1,000 catheter-days in the intervention group and 4.2 in the control group (binomial test, P=.14). CR infections were associated with the duration of ICU admission by multivariate logistic regression.

CONCLUSIONS

The data suggested that an active infection surveillance and control program could reduce the rate of CR

A novel dual-specificity protein kinase targeted to the chloroplast in tobacco

The NtDSK1 cDNA encoding a novel chloroplast-targeted protein kinase was identified in Nicotiana tabacum. It contains the kinase domain at the C-terminus and a putative regulatory domain at the N-terminus. The recombinant NtDSK1 underwent autophosphorylation of serine, threonine, and tyrosine residues, indicating that NtDSK1 encodes a functional dual-specificity protein kinase. The NtDSK1-green fluorescent protein fusion protein was targeted to chloroplasts. Furthermore, the NtDSK1 protein was immunodetected in chloroplast fractions isolated from tobacco seedlings. The NtDSK1 mRNA expression was developmentally regulated in different tissues, including anthers and germinating seeds, and strongly stimulated by gibberellin. The mRNA was rapidly light responsive during seedling growth. NtDSK1 may play a role in a light-regulated signaling process in tobacco.

The biological significance of phospholipase C beta 1 gene mutation in mouse sperm in the acrosome reaction, fertilization, and embryo development

PURPOSE

We carried out this study to evaluate the biological significance of phospholipase C beta 1 gene mutation in mouse sperm in the acrosome reaction, fertilization, and embryo development.

METHODS

Study subjects were divided into two groups according to the sperm [intact phospholipase C (PLC) beta 1 and PLC beta 1-/- C57BL/6J x CBA F1 mouse sperm] used. The positive acrosome reaction rate labeled with fluorescein isothiocyanate-Pisum sativum agglutinin, the fertilization rate, and the rate of embryos developed to the stage of morula or blastocyst in the two groups were compared.

RESULTS

The mouse sperm null for the PLC beta 1 gene showed a lower acrosome reaction rate than control sperm (69.2 vs 50.9%, P < 0.05). And the fertilization rate and the rate of embryos developed to the stage of morula or blastocyst were also lower in the group using PLC beta 1-/- mouse sperm compared to the intact group (P < 0.05; 73.5 vs 51.8% and 15.7 vs 4.3%, respectively).

CONCLUSIONS

Mutation of the PLC beta 1 gene in the mouse sperm reduces the acrosome reaction rate, fertilization rate, and embryo development rate, which may be the etiologic factors responsible for the low reproductive rate of PLC beta 1-/- mouse.

Telomerase expression prevents replicative senescence but does not fully reset mRNA expression patterns in Werner syndrome cell strains

Reduced replicative capacity is a consistent characteristic of cells derived from patients with Werner syndrome. This premature senescence is phenotypically similar to replicative senescence observed in normal cell strains and includes altered cell morphology and gene expression patterns. Telomeres shorten with in vitro passaging of both WRN and normal cell strains; however, the rate of shortening has been reported to be faster in WRN cell strains, and the length of telomeres in senescent WRN cells appears to be longer than that observed in normal strains, leading to the suggestion that senescence in WRN cell strains may not be exclusively associated with telomere effects. We report here that the telomere restriction fragment length in senescent WRN fibroblasts cultures is within the size range observed for normal fibroblasts strains and that the expression of a telomerase transgene in WRN cell strains results in lengthened telomeres and replicative immortalization, thus indicating that telomere effects are the predominant trigger of premature senescence in WRN cells. Microarray analyses showed that mRNA expression patterns induced in senescent WRN cells appeared similar to those in normal strains and that hTERT expression could prevent the induction of most of these genes. However, substantial differences in expression were seen in comparisons of early-passage and telomerase-immortalized derivative lines, indicating that telomerase expression does not prevent the phenotypic drift, or destabilized genotype, resulting from the WRN defect.

Congestion of right liver graft in living donor liver transplantation

BACKGROUND

Left liver graft from a small donor will not meet the metabolic demands of a larger adult recipient. One solution to this problem is to use a right liver graft without a middle hepatic vein (MHV). However, the need for drainage from the MHV tributaries has not yet been described.

METHODS

Five right liver grafts without a MHV were transplanted in patients including two hepatitis B virus-cirrhosis, two fulminant hepatic failure and one secondary biliary cirrhosis. The graft weight ranged from 650 to 1,000 g, corresponding to 48 to 83% of the standard liver volume of the recipients.

RESULTS

Two of five recipients were complicated with severe congestion of the right median sector immediately after reperfusion, followed by prolonged massive ascites and severe liver dysfunction. One of the patients died of sepsis with progressive hepatic dysfunction 20 days after the operation.

CONCLUSIONS

Preservation and reconstruction of the MHV tributaries is recommended to prevent congestion of the right liver graft without MHV.

Opacification of the intrahepatic portal veins during CT hepatic arteriography

PURPOSE

The purpose of this study was to ascertain the cause of opacification of the portal veins during CT hepatic arteriography (CTHA).

METHOD

A total of 155 consecutive patients with hepatocellular carcinoma were evaluated with CTHA as preoperative staging. The opacification of the portal veins during CTHA was categorized as opacification of the main portal vein, right or left branches of the main portal vein (generalized), and segmental or subsegmental portal veins (localized). Hepatic angiography was compared and possible causes were evaluated.

RESULTS

One hundred eight (70%) of 155 patients showed intrahepatic portal vein opacification at CTHA: generalized in 60 patients (39%) and localized in 48 patients (31%). Intrahepatic causes were arterioportal shunts due to hepatocellular carcinoma in 20 (19% of 108 patients), previous liver biopsy in 9 (8%), and portal vein thrombosis in 4 (4%). Extrahepatic cause was counted in 57 cases (53%) and was due to inflow of contrast material via nonmesenteric portal circulation through the gastric antrum, duodenum, and/or pancreas.

CONCLUSION

Intrahepatic portal veins are frequently opacified during CTHA, and the causes were arterioportal shunts through hepatocellular carcinoma, postbiopsy shunt, portal vein thrombosis, and inflow of contrast material via the nonmesenteric portal circulation.

Stenting with intravenous abciximab infusion for the treatment of left main coronary artery thrombosis during coronary angioplasty

A 67-year-old female patient complained of exertional precordial chest pain with radiation to the left shoulder occurring over a two-month period. An acute non-Q wave anterior myocardial infarction was diagnosed. On the third day of admission, coronary angiography revealed two-vessel disease with 73% luminal narrowing of the proximal left anterior descending coronary artery and 50% luminal narrowing of the mid-right coronary artery. The initial attempt to implant a NIR stent (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) was unsuccessful. We report on the successful rescue implantation of two MAC (Maximum Arterial re-Creation) stents (Advanced Medical Technologies, Germany), in conjunction with the infusion of abciximab for the treatment of an abrupt closure due to thrombus of the left main coronary artery.

The expression of pseudogene cyclin D2 mRNA in the human ovary may be a novel marker for decreased ovarian function associated with the aging process

PURPOSE

Our purpose was to investigate the expression pattern of cyclin D2 and pseudogene cyclin D2 mRNA in the human ovary with age.

METHODS

After extraction of the total RNA from ovarian tissues of 23 premenopausal patients, cyclin D2 and pseudogene cyclin D2 mRNAs were measured by the reverse transcription-polymerase chain reaction technique using cyclin D2 and pseudogene cyclin D2 specific primers. Analysis of the cyclin D2 and pseudogene cyclin D2 mRNA expression pattern with age and correlation analysis were carried out.

RESULTS

A 489-bp cyclin D2 band and a 441-bp pseudogene cycin D2 mRNA band were detected in the human ovarian tissue. While cyclin D2 mRNA expression showed a decreasing tendency with age (P = 0.17), pseudogene cyclin D2 mRNA expression increased with age (P < 0.05). Pseudogene cyclin D2 mRNA expression showed a negative correlation with cyclin D2 mRNA (R = -0.35, P < 0.03).

CONCLUSION

The expression of pseudogene cyclin D2 mRNA in the human ovary increases with age, which may be a novel marker for decreased ovarian function associated with the aging process.

Preoperative detection of hepatocellular carcinoma: ferumoxides-enhanced mr imaging versus combined helical CT during arterial portography and CT hepatic arteriography

OBJECTIVE

The purpose of this study was to compare ferumoxides-enhanced MR imaging with combined helical CT during arterial portography and CT hepatic arteriography for preoperative detection of hepatocellular carcinomas.

SUBJECTS AND METHODS

Twenty patients with 30 hepatocellular carcinomas underwent ferumoxides-enhanced MR imaging and combined helical CT during arterial portography and CT hepatic arteriography. The diagnosis was established by pathologic examination after surgical resection in 18 patients and by biopsy in two. The MR protocol included fast spin-echo with two echo times, T2(*)-weighted fast multiplanar gradient-recalled acquisition in the steady state, proton density-weighted fast multiplanar spoiled gradient-recalled echo, and T1-weighted fast multiplanar spoiled gradient-recalled echo images. The MR images of all sequences and the paired CT during arterial portography and CT hepatic arteriography images were independently evaluated by three radiologists on a segment-by-segment basis. Diagnostic accuracy was assessed with receiver operating characteristic analysis.

RESULTS

The accuracies (A(z) values) of ferumoxides-enhanced MR imaging and combined CT during arterial portography and CT hepatic arteriography for all observers were 0.964 and 0.948, respectively. The mean sensitivities of MR imaging and CT were 93% and 91%, respectively. The differences were not statistically significant. The mean specificity of MR imaging (99%) was significantly higher than that of combined CT during arterial portography and CT hepatic arteriography (94%).

CONCLUSION

Ferumoxides-enhanced MR imaging can be used successfully in place of combined CT during arterial portography and CT hepatic arteriography for the preoperative evaluation of patients with hepatocellular carcinomas.

Intestinal metastases from gastric adenocarcinoma: helical CT findings

PURPOSE

The purpose of this work was to describe the helical CT findings of intestinal metastasis from gastric adenocarcinoma.

METHOD

Twenty-three patients with intestinal metastasis from gastric adenocarcinoma found at helical CT were included. CT findings and clinical and pathologic data were reviewed.

RESULTS

The most common characteristic finding was target-like concentric bowel wall thickening (thick inner high-outer low, n = 18) involving multiple long segments with progressive thickening of the enhancing inner layer. Fifteen cases (65%) involved multiple sites, and the ascending colon (n = 12) and rectum (n = 11) were the two most common sites. Peritoneal carcinomatosis (n = 15, 65%) and bowel obstruction (n = 14, 61%) were common associated findings. Regarding the primary lesion, the majority was linitis plastica (n = 16) and poorly differentiated adenocarcinoma with or without signet-ring cell differentiation (n = 14).

CONCLUSION

Intestinal metastasis from gastric adenocarcinoma, especially of the linitis plastica type, most commonly showed target-like long segmental wall thickening with a characteristically thick inner enhancing layer on helical CT.

17Beta-estradiol inhibits proliferation of cultured vascular smooth muscle cells induced by lysophosphatidylcholine via a nongenomic antioxidant mechanism

OBJECTIVE

Lysophosphatidylcholine (lysoPC), an active component of oxidized low-density lipoprotein, stimulates proliferation of vascular smooth muscle cells (VSMC). We investigated the direct impact of 17beta-estradiol (E2) on the proliferation of VSMC from rat aorta.

RESULTS

VSMC derived from both female and male rats expressed estrogen receptors alpha and beta. Treatments with 1% fetal bovine serum or 5 microM lysoPC increased the incorporation of [3H]-thymidine in VSMC obtained from female rats. 17Beta-E2 did not alter the response to fetal bovine serum, but significantly suppressed the enhanced deoxyribonucleic acid synthesis which had been induced by lysoPC in a dose-dependent manner (10(-4)-10(-6) M). Estrogen also inhibited the proliferation of VSMC from male animals. ICI 182,780, a specific estrogen receptor antagonist, and 17alpha-E2, an inactive form of estradiol, also decreased the mitogenic response to lysoPC in VSMC. In addition, N-acetyl-L-cysteine, a potent antioxidant, inhibited the lysoPC effect. Flow cytometric analysis using the oxidation-sensitive probe 2',7'-dichlorofluorescin diacetate revealed that elevated intracellular formation of reactive oxygen species elicited with lysoPC was depressed significantly by 17beta-E2, ICI 182,780, or 17alpha-E2 as well as by N-acetyl-L-cysteine.

CONCLUSION

17Beta-E2 inhibits in vitro VSMC proliferation induced by lysoPC via a nongenomic antioxidant mechanism.