Response to Neoadjuvant Therapy and Prognosis in Patients with Resectable Pancreatic Cancer: A Propensity Score Matching Analysis

Background/Aims

Controversy regarding the effectiveness of neoadjuvant therapy for resectable pancreatic ductal adenocarcinoma (PDAC) still exists. Here, we aimed to identify the potential benefits of neoadjuvant therapy followed by surgery for resectable PDAC.

Methods

We reviewed radiologically resectable PDAC patients who received resection with curative intent at a tertiary hospital in South Korea between January 2012 and August 2019. A total of 202 patients underwent curative resection for resectable PDAC 167 underwent surgical resection first during this period, and 35 received neoadjuvant chemotherapy/chemoradiation therapy followed by surgery. Resectable PDAC patients were subdivided, and 13 propensity score matching (PSM) was performed to reduce selection bias.

Results

Compared with the group that received surgery first, the group that received neoadjuvant treatment followed by surgery had significantly smaller tumors (22.0 mm vs 27.0 mm, p=0.004), a smaller proportion of patients with postoperative pathologic T stage (p=0.026), a smaller proportion of patients with lymphovascular invasion (20.0% vs 40.7%, p=0.022), and a larger proportion of patients with negative resection margins (74.3% vs 51.5%, p=0.049). After PSM, the group that received neoadjuvant therapy had a significantly longer progression-free survival than those in the group that underwent surgery first (29.6 months vs 15.1 months, p=0.002). Overall survival was not significantly different between the two groups after PSM analysis.

Conclusions

We observed significantly better surgical outcomes and progression-free survival with the addition of neoadjuvant therapy to the management of resectable PDAC. However, despite PSM, there was still selection bias due to the use of different regimens between the groups receiving surgery first and neoadjuvant therapy. Large homogeneous samples are needed in the future prospective studies.

Injecting NMDA and Ro 25-6981 in insular cortex induce neuroplastic changes and neuropathic pain-like behaviour

BACKGROUND

Neuropathic pain is associated with abnormal sensitivity of the central nervous system. Although the mechanism underlying the development of sensitization remains to be fully elucidated, recent studies have reported that neuroplastic changes in the pain circuitry may be involved in hypersensitivity associated with neuropathic pain. However, it is difficult to investigate such phenomena in existing animal pain model. Therefore, in this study, we developed a novel animal model - the circuit plasticity reconstruction (CPR) model - to mimic central sensitization associated with neuroplastic changes.

METHOD

NMDA and Ro 25-6981 were injected into the right insular cortex of Sprague-Dawley rats, while electrical stimulation was delivered to the contralateral hind paw. Mechanical allodynia was tested by von Frey test with up-down method, and neuroplastic changes were confirmed by PSA-NCAM-positive immunostaining.

RESULT

The mechanical withdrawal threshold of the left hind paw decreased beginning 1 day after CPR modelling and persisted until day 21 comparing to the modified CPR 1 (mod-CPR 1) group (CPR: 91.68 ± 1.8%, mod-CPR 1: 42.71 ± 3.4%, p < 0.001). In contrast, mod-CPR 2 surgery without electrical stimulation did not induce mechanical allodynia. Immunostaining for PSA-NCAM also revealed that neuroplastic changes had occurred in the CPR group.

CONCLUSION

Our results demonstrated that CPR modelling induced neuroplasticity within the insular cortex, leading to alterations in the neural circuitry and central sensitization.

SIGNIFICANCE

This article represents that the CPR model can mimic the neuropathic pain derived by neuroplastic changes. Our findings indicate that the CPR model may aid the development of novel therapeutic strategies for neuropathic pain and in elucidating the mechanisms underlying pain induced by central sensitization and neuroplastic changes.

[Clinical application of pain-related evoked potentials]

Pain-related evoked potentials (PREPs) represent a novel method for the evaluation of peripheral and central nociceptive pathways, e.g. in the diagnosis of small fiber neuropathy (SFN) or after therapeutic interventions for headache. Compared to contact heat-evoked and laser-evoked potentials, recording of PREPs is less stressful for the subjects and technically less demanding. The clinical usefulness of PREPs has been described for SFN associated with diabetes, HIV and hepatitis C infections as well as in headache and facial pain disorders. They have also been evaluated after interventional methods, such as direct current stimulation (tDCS). The article reviews and discusses the advantages and pitfalls of this technique in the context of recent clinical studies as compared to other paradigms of peripheral electrical stimulation and delineates perspectives and possible indications.

Efficacy of Pregabalin in the Treatment of Trigeminal Neuralgia

This prospective, open-label study aimed to evaluate the efficacy of pregabalin treatment in patients suffering from trigeminal neuralgia with and without concomitant facial pain. Fifty-three patients with trigeminal neuralgia (14 with concomitant chronic facial pain) received pregabalin (PGB) 150-600 mg daily and were prospectively followed for 1 year. The primary outcome was number of patients pain free or with reduction of pain intensity by > 50% and of attack frequency by > 50% after 8 weeks. Secondary outcome was sustained pain relief after 1 year. Thirty-nine patients (74%) improved after 8 weeks with a mean dose of 269.8 mg/day (range 150-600 mg/day) PGB: 13 (25%) experienced complete pain relief and 26 (49%) reported pain reduction > 50%, whereas 14 (26%) did not improve. Patients without concomitant facial pain showed better response rates (32 of 39, 82%) compared with patients with concomitant chronic facial pain (7 of 14, 50%, P = 0.020). Concomitant chronic facial pain appears to be a clinical predictor of poor treatment outcome. PGB appears to be effective in the treatment of trigeminal neuralgia.

Significance of E2F-1 overexpression in epithelial ovarian cancer

E2F-1 is a downstream regulator of the Rb pathway and is a transcription factor that plays a key role in the control of cell cycle progression. Deregulation of E2F-1 expression and Rb pathway is involved in carcinogenesis. The aim of this study was to evaluate E2F-1 expression and Rb pathway alteration and to elucidate their correlation with clinical and pathologic parameters in epithelial ovarian cancer (EOC). We investigated overexpression of E2F-1 and alterations of p16(INK4a), cyclin D1, CDK4, and pRb using immunohistochemistry and tissue microarray methods in 72 EOC patients. Overexpression of E2F-1 was detected in 45.8% of samples. The overall abnormal expression frequencies of p16(INK4a), cyclin D1, CDK4, and pRb were 33.3%, 11.1%, 12.5%, and 38.9%, respectively. E2F-1 overexpression was not associated with alteration of the Rb pathway. E2F-1 overexpression was correlated with FIGO stage, histologic grade, and mitotic index; it was a valuable prognostic variable along with FIGO stage in the multivariated analysis. The results suggest that E2F-1 has a growth-promoting effect in EOC and that E2F-1 overexpression may provide a useful prognostic indicator for EOC.

BARCSoySNP23: a panel of 23 selected SNPs for soybean cultivar identification

This report describes a set of 23 informative SNPs (BARCSoySNP23) distributed on 19 of the 20 soybean linkage groups that can be used for soybean cultivar identification. Selection of the SNPs to include in this set was made based upon the information provided by each SNP for distinguishing a diverse set of soybean genotypes as well as the linkage map position of each SNP. The genotypes included the ancestors of North American cultivars, modern North American cultivars and a group of Korean cultivars. The procedure used to identify this subset of highly informative SNP markers resulted in a significant increase in the power of identification versus any other randomly selected set of equal number. This conclusion was supported by a simulation which indicated that the 23-SNP panel can uniquely distinguish 2,200 soybean cultivars, whereas sets of randomly selected 23-SNP panels allowed the unique identification of only about 50 cultivars. The 23-SNP panel can efficiently distinguish each of the genotypes within four maturity group sets of additional cultivars/lines that have identical classical pigmentation and morphological traits. Comparatively, the 13 trinucleotide SSR set published earlier (BARCSoySSR13) has more power on a per locus basis because of the multi-allelic nature of SSRs. However, the assay of bi-allelic SNP loci can be multi-plexed using non-gel based techniques allowing for rapid determination of the SNP alleles present in soybean genotypes, thereby compensating for their relatively low information content. Both BARCSoySNP23 and BARCSoySSR13 were highly congruent relative to identifying genotypes and for estimating population genetic differences.

Cumulus cells apoptosis as an indicator to predict the quality of oocytes and the outcome of IVF-ET

PURPOSE

Our purpose was to establish an evaluation system for oocyte quality based on the incidence of cumulus cells apoptosis and to examine the effect of coculture, using autologous cumulus cells, on the outcome of IVF-ET according to proliferative activities of helper cells and the incidence of cumulus cells apoptosis.

METHODS

Cumulus cell masses were collected from 91 mature oocytes among 330 oocytes retrieved from a total of 34 IVF-ET cycles with tubal infertility and unexplained infertility. The incidence of apoptosis in cumulus cells was assessed by apoptosis detection kit fluorescein. On ovum pick up, 2nd day embryos were cocultured with autologous cumulus cells. Prior to coculture, in vitro proliferative activity of cumulus cells was evaluated.

RESULTS

Cumulus cells from patient groups over 40 years old had a significantly increased apoptosis incidence, a lower fertilization rate, and the decreased number of oocytes retrieved compared to the other age groups (P < .05). The incidence of cumulus cells apoptosis was significantly lower when the number of oocytes retrieved was 5 or less (P < .05). Cumulus cells from fertilized oocytes (0.43 +/- 0.07%) and those from patients who became pregnant (0.44 +/- 0.11%) following IVF-ET showed a significantly lower incidence of apoptosis compared to those of unfertilized oocytes (1.80 +/- 0.35%; P < .001) and the nonpregnant group (0.81 +/- 0.10%; P < .05). Embryo quality also had a negative correlation with the incidence of cumulus cells apoptosis. Coculture of fertilized oocytes with cumulus cells with high proliferative activity resulted in improved rates of implantation and pregnancy compared to that with poor active cumulus cells. No significant difference was found between the in vitro proliferative activity of cumulus cells and the incidence of cumulus cells apoptosis (P < .063).

CONCLUSIONS

The age of women might influence the incidence of apoptosis in cumulus cells, and the increased incidence of apoptosis is associated with the number of oocytes retrieved, the fertilization rate, and the pregnancy outcome following IVF-ET. These results suggest that the incidence of cumulus cells apoptosis can be used in predicting oocyte quality, outcome of IVF-ET, and age-related decline in fertility.

Vasoactive diadenosine polyphosphates in human placenta: possible candidates in the pathophysiology of pre-eclampsia?

BACKGROUND

One hypothesis of the pathophysiology of pre-eclampsia is that placentally derived, yet unidentified, vasoactive factors are released into the maternal circulation, causing hypertension.

OBJECTIVE

To determine if diadenosine polyphosphates, new potent vasoconstrictors, are present in human placenta.

METHODS AND RESULTS

Human placental tissue was homogenated and fractionated by size-exclusion chromatography, affinity chromatography, anion-exchange chromatography and reversed-phase chromatography. In fractions purified to homogeneity, diadenosine diphosphate, diadenosine triphosphate, diadenosine tetraphosphate, diadenosine pentaphosphate, diadenosine hexaphosphate and diadenosine heptaphosphate were identified by matrix-assisted laser desorption/ionization mass spectrometry, retention-time comparison and enzymatic cleavage analysis.

CONCLUSIONS

The presence of diadenosine polyphosphates in human placenta makes them possible candidates for involvement in the pathophysiology of pre-eclampsia. However, their contribution to the pathophysiology of eclampsia requires substantiation in further studies.

Increased vascular growth in hemodialysis patients induced by platelet-derived diadenosine polyphosphates

BACKGROUND

Enhanced vascular smooth muscle cell (VSMC) growth is one hallmark of atherosclerosis. One mechanism responsible for stimulating arterial smooth muscle cell growth is the release of growth factors from platelets aggregating at endothelial lesions. Since in end-stage renal failure (ESRF) atherogenesis is markedly accelerated, the release of VSMC growth factors on aggregation of platelets from hemodialysis patients, ESRF patients in the predialysis stage, and healthy subjects was examined.

METHODS

Platelets were activated by thrombin, and the supernatant was tested for growth stimulation in VSMCs from rat aorta. The cell proliferation rate was determined by [(3)H]-thymidine incorporation in VSMCs. The diadenosine polyphosphate (Ap(n)A with N = 3 to 6) content in the supernatant and in intact platelets was determined using a chromatographic assay established on the basis of affinity- and reversed-phase chromatographic methods.

RESULTS

The thrombin-activated platelet supernatant from hemodialysis patients (N = 15) increased the [(3)H]-thymidine incorporation rate in VSMC s in comparison to the supernatant of healthy control subjects (N = 17, counts/supernatant of 10(6) stimulated platelets +/- SEM, 604 +/- 71 vs. 364 +/- 45, P < 0.05). The addition of the selective P2-receptor blocker pyridoxal-phosphate-6-azophenyl-2,4-disulfonic acid to supernatants inhibited the stimulatory effects of Ap(n)A on the growth of vascular smooth muscle cells (219 +/- 53 vs. 156 +/- 71 counts/supernatant of 106 stimulated platelets +/- SEM). The Ap(n)A (N = 3 to 6) amount of thrombin-activated platelet supernatants from hemodialysis patients was significantly higher than in platelets from 10 healthy control subjects (Ap(3)A, 119 +/- 32 vs. 12 +/- 3; Ap(4)A, 154 +/- 59 vs. 43 +/- 20; Ap(5)A, 39 +/- 14 vs. 13 +/- 6; Ap(6)A, 42 +/- 19 vs. 2 +/- 1 fg/platelet +/- SEM, each P < 0.05, N = 10). The intracellular Ap(n)A (N = 3 to 6) amount of intact platelets from hemodialysis patients (N = 61) was significantly higher than that from healthy control subjects [N = 30, Ap(n)A amount (fg/platelet +/- SEM): Ap(3)A, 366 +/- 68 vs. 14.7 +/- 1; Ap(4)A, 336 +/- 48 vs. 19 +/- 2; Ap(5)A, 227 +/- 35 vs. 10 +/- 1; Ap(6)A, 141 +/- 45 vs. 4 +/- 1; each P < 0.01].

CONCLUSIONS

The increased amount of dinucleoside polyphosphate in platelets from hemodialysis patients may be an important additional atherogenic factor.

Prophylactic efficacy of a new gentamicin-releasing urethral catheter in short-term catheterized rabbits

OBJECTIVE

To describe an indwelling urethral catheter coated with gentamicin sulphate on the inner and outer surface of the catheter, and to evaluate the efficacy and safety of this catheter in preventing catheter-associated infections in rabbits. Materials and methods Sixty rabbits were divided equally into control and experimental groups which were then subdivided equally according to the duration of catheterization (1, 3 and 5 days). Silicone-treated latex catheters were used in the control group and gentamicin-releasing catheters in the experimental group. Urine samples and surface swabs from the catheter were cultured for bacteriological assessment, and the catheter surface examined by scanning electron microscopy to structurally analyse the biofilms.

RESULTS

The gentamicin-releasing catheter reduced the incidence of bacteriuria (defined as > or = 100 c.f.u./mL) after both 3 and 5 days of catheterization (eight and 10 rabbits, respectively, for the control catheter, vs two and four rabbits for the gentamicin-releasing catheter, P < 0.05). The surfaces of the gentamicin-releasing catheter were colonized less often than those of the control catheter after both 3 and 5 days (eight and 10, respectively, for the control, vs one and four for the gentamicin-releasing catheter, P < 0.05). Scanning electron microscopy showed the formation of bacterial biofilm throughout the 3-day and 5-day control catheters, but deterioration of the bacterial biofilm was visible on the surface of the gentamicin-releasing catheters.

CONCLUSION

This new gentamicin-releasing catheter produced an antibacterial barrier which inhibited catheter-associated urinary tract infection with no toxicity for at least 5 days. These in vivo studies suggest that this new catheter may be useful for controlling infection, with systemic and local safety, in patients undergoing short-term indwelling urethral catheterization.

Formation of cadherin-expressing brain nuclei in diencephalic alar plate divisions

During the formation of brain nuclei, the vertebrate neural tube is partitioned into distinct embryonic divisions. In this study, the expression of three members of the cadherin family of adhesion molecules (cadherin-6B, cadherin-7, and R-cadherin) was mapped to study the differentiation of gray matter in the division so that diencephalic alar plate of chicken embryos from embryonic day 3 (E3) to E10. At early stages of development (E3-E4), each cadherin is expressed in restricted regions of the diencephalic wall of the neural tube. The borders of some of the expression domains coincide with divisional boundaries. As the mantle layer is formed and increases in thickness from E4 to E8, morphologically discernible aggregates of cells appear that express the three cadherins differentially. These aggregates represent the anlagen of specific diencephalic brain nuclei, e.g., the lateroanterior nucleus, the ventral geniculate nucleus, the nucleus rotundus, the perirotundic area, the principal precommissural nucleus, and the lateral spiriform nucleus. Most of the cadherin-expressing diencephalic nuclei studied in this work apparently derive from a single embryonic division and remain there. The divisional boundaries are replaced gradually by the borders of cadherin-expressing brain nuclei. The current results support the idea that cadherins confer differential adhesiveness to developing structures of gray matter in the diencephalic alar plate. Moreover, they suggest that each cadherin plays a role in the formation of specific brain nuclei within the diencephalic divisions.

Vocal tremor reduction with deep brain stimulation

We present a case illustration of the significant effect that deep brain stimulation (DBS) of the thalamus can have on vocal tremor. A 72-year-old female with a history of essential tremor was noted preoperatively to have a moderate vocal tremor (3 on a scale of 1-5). Following bilateral DBS of the thalamus, the vocal tremor rating improved to 1. Acoustic analysis demonstrated her vocal tremor to be affecting the amplitude of her voice at 5.58 Hz preoperatively, at 1. 93 Hz postoperatively with both leads on and at 1.54 Hz with only the left lead on. A videotaped endoscopic view of the patient's vocal cords (presented at the 1999 ASSFN meeting) clearly illustrated the dramatic changes apparent in the vocal tremor when the stimulators were turned on and off.

Placement of deep brain stimulators into the subthalamic nucleus

We present our technique for deep brain stimulation (DBS) of the subthalamic nucleus (STN) and include information which may be helpful in general DBS. With the patient in a stereotactic head frame, the anterior and posterior commissures are identified on SPGR-sequence magnetic resonance imaging (MRI). STN coordinates are based on a stereotactic brain atlas at 12 mm lateral, 2 mm posterior and 5 mm caudal to the midcommissural point. Surgical navigation software allows for planning of the trajectory. Electromyography is used to quantitatively measure tremor responses to macrostimulation. Permanent lead placement is confirmed with intraoperative fluoroscopy and postoperative MRI.

Formation of cadherin-expressing brain nuclei in diencephalic alar plate divisions

During the formation of brain nuclei, the vertebrate neural tube is partitioned into distinct embryonic divisions. In this study, the expression of three members of the cadherin family of adhesion molecules (cadherin-6B, cadherin-7, and R-cadherin) was mapped to study the differentiation of gray matter in the divisions of the diencephalic alar plate of chicken embryos from embryonic day 3 (E3) to E10. At early stages of development (E3-E4), each cadherin is expressed in restricted regions of the diencephalic wall of the neural tube. The borders of some of the expression domains coincide with divisional boundaries. As the mantle layer is formed and increases in thickness from E4 to E8, morphologically discernible aggregates of cells appear that express the three cadherins differentially. These aggregates represent the anlagen of specific diencephalic brain nuclei, e.g., the lateroanterior nucleus, the ventral geniculate nucleus, the nucleus rotundus, the perirotundic area, the principal precommissural nucleus, and the lateral spiriform nucleus. Most of the cadherin-expressing diencephalic nuclei studied in this work apparently derive from a single embryonic division and remain there. The divisional boundaries are replaced gradually by the borders of cadherin-expressing brain nuclei. The current results support the idea that cadherins confer differential adhesiveness to developing structures of gray matter in the diencephalic alar plate. Moreover, they suggest that each cadherin plays a role in the formation of specific brain nuclei within the diencephalic divisions.

Relationships between concentrations of tumor necrosis factor-alpha and nitric oxide in follicular fluid and oocyte quality

PURPOSE

Our objective was to explain a relationship between concentrations of tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) in follicular fluid, oocyte quality, and outcomes of in vitro fertilization--embryo transfer (IVF-ET).

METHODS

The concentrations of TNF-alpha and NO were measured in 115 follicular fluid samples collected from 43 patients undergoing IVF-ET program, due to tubal obstruction, some with endometriosis (8 patients) or hydrosalpinx (5 patients). A correlation of these factors concentrations and the oocyte quality, the oocyte maturity, and infertility-associated diseases was analyzed.

RESULTS

No correlation was found between concentrations of NO and TNF-alpha in follicular fluid. NO concentrations in follicular fluids were significantly higher in patients with endometriosis (P < 0.001) or hydrosalpinx (P < 0.01) compared to the patients with just tubal obstruction. Follicular NO concentration differences according to oocyte maturity and oocyte quality were not found. In contrast, TNF-alpha concentrations in follicular fluids were significantly higher in poor quality oocytes (P < 0.05) but were not associated with infertility-associated diseases, such as hydrosalphinx or endometriosis,and the oocyte maturity. No significant differences in follicular levels of NO and TNF-alpha as well as IVF-ET parameters of pregnant and nonpregnant groups were revealed.

CONCLUSIONS

There is no significant correlation between the concentrations of NO and TNF-alpha in follicular fluid. NO levels in follicular fluid are altered in infertility-associated diseases. However, TNF-alpha levels but not NO levels influence oocyte quality. These results suggest that the production of NO and TNF-alpha in follicular fluid may be regulated via different pathways and can be tempered with infertility-associated diseases, thereby influencing oocyte quality locally.

Angiolymphoid hyperplasia with eosinophilia showing characteristics of Kimura's disease

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a rare benign condition affecting principally the head and neck region of young females. We describe a 42-year-old female patient of ALHE showing the typical changes of endothelial cells and features similar to Kimura's disease in histologic and immunohistochemical findings.

Long-term results of percutaneous endourologic management of renal infundibular stricture

PURPOSE

The long-term result of percutaneous endourologic management in the relief of infundibular stricture is not clear. We reviewed the long-term efficacy in our series of patients.

PATIENTS AND METHODS

Twenty-seven patients underwent percutaneous endourologic management between August 1990 and February 1996. This study included the 21 who could be followed for more than 2 years (mean 4.8 years). The causes of stricture were tuberculosis (N = 18; 86%) and stone (N = 3; 14%). We made a cold-knife incision in eight patients; the others underwent only dilation with fascial dilators from 20F to 30F. Success was defined as symptomatic improvement and radiographic resolution of obstruction.

RESULTS

The overall success rate was 76% (16 of 21). Seven of the eleven patients (64%) with concomitant ureteral stricture had a successful result. In the nine patients with multiple infundibular strictures, five procedure (56%) were successful. The success rates of the cold-knife or fascial dilator were 88% (7 of 8) and 69% (8 of 13), respectively. In the five patients in whom the procedure failed, ureteral stricture was associated in four and multiple infundibular strictures in four. All of them had tuberculous infundibular strictures. No significant difference in the success rate was observed according to the duration of indwelling catheter. There was no significant complication except pyelonephritis in four patients, which was controlled with conservative treatment.

CONCLUSIONS

Percutaneous endourologic management is an effective and safe procedure to treat renal infundibular stricture. Risk factors for failure are multiple infundibular strictures and concomitant ureteral stricture. If the procedure does fail, other treatments have not been compromised. Cold-knife incision seems to be more effective than dilation.

MR high-resolution blood oxygenation level-dependent venography of occult (low-flow) vascular lesions

A new technique for detecting vascular malformations, high-resolution BOLD venography (HRBV), is described. This technique relies on the BOLD principle for detecting deoxygenated blood in low-flow malformations. HRBV images are acquired using a modified 3D gradient-echo with voxel volumes of 0.5 x 0.5 x 2 mm3. The magnitude data are masked with the phase images to enhance visibility of the venous structures and are displayed using the minimum intensity projection. Preliminary results for 10 patients show that HRBV is more sensitive in detecting cavernomas than is T2-weighted imaging, and lesions that are presumed to be telangiectasias are detected only with this technique.

Collagen studies for pediatric ureteropelvic junction obstruction

OBJECTIVES

Ureteropelvic junction (UPJ) obstruction is the most common form of urinary tract obstruction in pediatrics. There is controversy regarding the need for early surgical intervention in many patients with apparent neonatal UPJ obstruction. To demonstrate the differences in type and amount of collagen in adult and pediatric UPJ obstruction, collagen studies were performed.

METHODS

The experimental groups are 9 pediatric patients with UPJ obstruction and 13 adult patients with UPJ obstruction. Six patients with normal UPJ were assigned as controls for each experimental group. The collagen content of UPJ was quantitated by hydroxyproline analysis. Immunohistochemical staining and Western blotting for collagen types I and III were performed.

RESULTS

The collagen content of pediatric UPJ was significantly lower in value than that of adult UPJ (P < 0.05). Immunohistochemical staining revealed that collagen type I was located in interfascicular space and collagen type III was located in intrafascicular space in both age groups. In Western blotting the relative intensity of collagen type III for pediatric UPJ was weaker than that of adult groups.

CONCLUSIONS

These results suggest that a larger series of patients should be examined to determine whether quantitative analysis for collagen types I and III would provide some kind of prognostic test for UPJ outcome in pediatric patients.

Head injuries in children from plastic hairbeads

BACKGROUND

Plastic hairbeads are often worn as decorative hair fasteners by children. Serious, penetrating head injuries may result from their use and have been observed in some children following a fall.

OBJECTIVE

The objective of this report is to describe the imaging findings in children who have sustained head injury while wearing plastic hairbeads.

MATERIALS AND METHODS

Three children with significant head injuries resulting from embedded hairbeads are described. Three additional cases of minor head injury reported to the Consumer Product Safety Commission are summarized.

RESULTS

One child sustained a minimally depressed skull fracture without brain injury. The second child required surgical repair of a depressed skull fracture complicated by a parenchymal hemorrhage and dural tear. A third child required surgical evacuation of an organized, liquefied epidural hematoma 2 weeks after an initial evaluation at an outside emergency room.

CONCLUSION

Children wearing plastic hairbeads are at risk for severe head injury following a fall. Caution must accompany their use.

The effects of monoclonal antibodies against iC3b receptors in mice with experimentally induced disseminated candidiasis

CR3 (iC3b receptor), composed of CD11b/CD18, is a beta 2 integrin. A protein that shares antigenic and structural homology with the alpha-chain of CD11b/CD18 has been isolated from the surface of Candida albicans. This molecule is thought to be essential in the pathogenesis of disseminated candidiasis. To evaluate the effects of anti-iC3b receptor antibodies on adhesion between human dermal microvascular endothelial cells (HDMEC) and C. albicans, and in treatment of candidal infection, a binding assay of C. albicans to cultured HDMEC was performed in vitro. An anti-iC3b receptor-specific monoclonal antibody was administered to mice infected with C. albicans. The mice were monitored for mortality and renal involvement by culture and histopathological findings. Flow cytometric analysis demonstrated surface expression of iC3b receptor on C. albicans. The adherence of C. albicans to HDMEC was significantly decreased by treatment with anti-iC3b receptor antibodies. Anti-iC3b receptor antibodies significantly increased the survival time and rate while lowering the renal fungal burden. The iC3b receptors are involved in the adherence of C. albicans to vascular endothelial cells and are likely to be involved in the pathogenesis of disseminated candidiasis. The increased survival in mice infected with C. albicans after treatment with anti-iC3b receptor antibodies indicates that this modality may be beneficial for future development of a new therapy for candidiasis.

A genetic system to identify DNA polymerase beta mutator mutants

DNA polymerase beta (pol beta) is a 39-kDa protein that functions in DNA repair processes in mammalian cells. As a first step toward understanding mechanisms of polymerase fidelity, we developed a genetic method to identify mammalian pol beta mutator mutants. This screen takes advantage of a microbial genetics assay and the ability of rat pol beta to substitute for Escherichia coli DNA polymerase I in DNA replication in vivo. Using this screen, we identified 13 candidate pol beta mutator mutants. Three of the candidate mutator mutants were further characterized in vivo and shown to confer an increased spontaneous mutation frequency over that of wild-type pol beta to our bacterial strain. Purification and subsequent analysis of one of our putative mutator proteins, the pol beta-14 protein, showed that it possesses intrinsic mutator activity in four different assays that measure the fidelity of DNA synthesis. Therefore, residue 265, which is altered in pol beta-14 and another of our mutant proteins, pol beta-166, is probably critical for accurate DNA synthesis by pol beta. Thus, our genetic method of screening for pol beta mutator mutants is useful in identifying active mammalian DNA polymerase mutants that encode enzymes that catalyze DNA synthesis with altered fidelity compared with the wild-type pol beta enzyme.

Characterization of DNA polymerase beta mutants with amino acid substitutions located in the C-terminal portion of the enzyme

We used quantitative complementation assays to characterize individual DNA polymerase beta (Pol beta) mutants for their ability to function in DNA replication and DNA repair. We also describe a screen for detecting mutator activity of DNA polymerase beta mutants. By using these bioassays, together with DNA polymerase activity gels, we characterized 15 new DNA polymerase beta mutants that display a wide spectrum of phenotypes. Most of these mutants are generally defective in their ability to synthesize DNA. However, two of our Pol beta mutants show more complex phenotypes: they are able to function in DNA repair but unable to participate in DNA replication. One of our mutants displays mutator activity in vivo. Our work provides a model to study mutant mammalian enzymes in Escherichia coli with phenotypes that are otherwise difficult to assess.

Vasal anastomoses in dogs using contact neodymium:yttrium aluminum garnet (Nd:YAG) laser

The purpose of this study is to evaluate the contact Nd:YAG laser system for vasal anastomosis in the animal model. Eighteen mongrel dogs were used. In this study, two major groups--control and laser--were defined. In the control group, vas anastomoses were performed with conventional microsurgical technique in six dogs. In the laser group, we performed contact laser assisted vas anastomosis (CLAVA) in 12 dogs by means of a contact Nd:YAG laser with synthetic sapphire probe (ERP4), emitted 2.0 sec pulse duration of minimum 1 watt to maximum 10 watts power. The time needed for completion of the vasal anastomosis in CLAVA group was 2-3 min; in the control group, approximately 25 min. The patency rate did not differ in these two groups; however, microscopic sperm granuloma formation was 16.7% (2/12) in the control group but 0% (0/12) in the CLAVA group. In conclusion, CLAVA is a fast and simple technique for vasal anastomosis and there were no significant complications, sperm granuloma, or even significant swelling or hematoma in any animal in this experiment.

Two cases of nickel dermatitis showing vitiligo-like depigmentations

The authors reviewed two patients showing "vitiligo-like depigmentations" where the skin had been in close contact with a metal spectacle frame made of nickel alloy. In spite of the hypersensitivity to nickel in both patients, they showed clinical and histologic findings indicate that the formation of "vitiligo-like depigmentation" does not result from posinflammatory hypopigmentation but from chemical hypomelanosis. We could not explain the underlying mechanisms; however, the speculation that the "vitiligo-like depigmentation" may come from the direct effect of the nickel itself, prompted us to report these cases.

Clinical experience in 200 renal transplants at Catholic Medical Center

Between March, 1969, and April, 1986, two hundred of renal allograft recipients were treated with either cyclosporine (CsA) + prednisone (n=53) or azathioprine (Aza) + prednisone (n = 147). On October 31, 1986, the actuarial patient survival rate at two years was 75% for all patient group. The corresponding graft survival rate at two years was 68 % for all patients. The actuarial patient survival rate at two years was 71% in the Aza group, and 94% in the CsA group including recipients converted from CsA to Aza (3 cases), which was statistically significant (p<.001), and the corresponding graft survival rate was 65% and 80%: the difference was not statistically significant. In the CsA-treated group, excluding converter from CsA to Aza (3 cases), however, the graft survival rate at two years was 91%, which was statistically significant (p = .0056). There was no significant difference of graft survival rate between the recipients who received DST vs non-DST in CsA-treated group. It was difficult to evaluate the recipients who were given DST due to a small number of cases and short follow-up period. In either, the Aza-or the CsA-treated group, the graft survival rates were higher in HLA identical LRD group than in either haplo-identical or mismatched LRD group. Total of 63 patients, who received kidney transplantation expired. The most frequent cause of death in 17.5% of cases was uremia per se due to graft failure, followed by infection (14.7%), vascular (14.3%), and cardiac (11.1%). The most commonly encountered posttransplant complications in order of frequency were as follows: erythrocytosis (18.0%), pneumonia (15.0%), urinary tract infections (14.0%), herpetic infections (12.0%), fungal infection (11.5%), posttransplant diabetes (8.5%), technical (5.0%) and others.

Postextrasystolic T wave changes in normal canine hearts

Premature ventricular beats were induced at variable coupling intervals and postextrasystolic T wave changes were observed following various postextrasystolic cycle lengths in 19 closed chest dogs with normal hearts. Following relatively longer postextrasystolic cycle lengths, reversal of the T wave polarity was seen in six dogs (31%), only T wave amplitude changes were seen in 6 dogs (31%), and no significant T wave changes were seen in seven dogs (38%). It was concluded that postextrasystolic T wave changes occur in normal hearts and have no useful diagnostic values.

Electrophysiologic effects of mexiletine on normal and ischemic ventricles

The effects of mexiletine on ventricular electrophysiologic properties were studied in seven normal and ten ischemic canine ventricles. Ventricular fibrillation threshold was significantly increased and idioventricular automaticity was significantly suppressed after intravenous administration of 2 mg/kg of mexiletine. Diastolic threshold, effective refractory period and ventricular conduction time were all increased slightly after the drug administration, although the changes were not statistically significant. Rapidly repetitive responses and/or fibrillation were induced in the ischemic ventricle by two early premature beats in six of ten dogs, but these serious arrhythmias could be induced in none of the ten dogs after mexiletine pretreatment. The study indicates that the mode of action of mexiletine is similar to that of lidocaine and the drug is an effective antiarrhythmic agent in preventing ventricular arrhythmias in dog ventricles during myocardial ischemia.

Effects of thioridazine (Mellaril) on ventricular electrophysiologic properties

The effects of therapeutic and toxic doses of thioridazine (Mellaril) (10 and 50 mg/kg body weight, respectively) on ventricular electrophysiologic properties were studied in 12 anesthetized dogs. Threshold pacing currents (diastolic threshold), effective refractory period and conduction time were significantly increased, and idioventricular automaticity was suppressed after administration of 10 mg/kg of thioridazine; the effects were much more pronounced after administration of 50 mg/kg. Rapidly repetitive responses or tachycardia could be induced in the ventricle by two early premature beats in 9 of the 12 dogs after the 50 mg/kg dose, but they did not occur before drug administration or after the 10 mg/kg dose. These results indicate that the antiarrhythmic and arrhythmogenic effects of thioridazine are dose-dependent and that careful monitoring with frequent electrocardiograms is needed for patients receiving large doses of this drug.

Effects of methylprednisolone on ventricular arrhythmias during acute myocardial ischaemia

The effects of methylprednisolone (50 mg.kg-1) on the incidence of ventricular tachycardia and fibrillation and on ventricular fibrillation threshold were studied during acute coronary occlusion in anaesthetised dogs. Ventricular tachycardia and/or ventricular fibrillation occurred in 11 of the 16 animals (69%) both before and after methylprednisolone pretreatment. The mean ventricular fibrillation threshold of 10 dogs was 10.1 +/- 1.8 mA before methylprednisolone and it increased slightly to 13.3 +/- 2.3 mA after the drug. This difference was not statistically significant (P greater than 0.2).

Effects of verapamil on ventricular rhythm during acute coronary occlusion

The effects of verapamil on electrophysiologic parameters of the ventricle were studied during acute coronary occlusion in anesthetized open-chest dogs. Those parameters measured in the study were idioventricular automaticity, ventricular conduction, and fibrillation threshold. The incidence of rapidly repetitive beats and fibrillation induced by two successive premature beats was also studied. Verapamil significantly decreased idioventricular automaticity (in five dogs), improved conduction through the ischemic area (in six dogs), and increased fibrillation threshold of the ischemic ventricular (in eight dogs). The drug was effective in abolishing rapidly repetitive beats and fibrillation induced by closely coupled premature beats during acute coronary occlusion. Rapidly repetitive beats occurred in nine out of 15 dogs and these repetitive beats were degenerated into fibrillation in seven dogs before verapamil. Following pretreatment with the drug, rapidly repetitive beats and fibrillation occurred in none of the 15 dogs. The results indicate that verapamil can be very effective against ventricular arrhythmias occurring in association with myocardial infarction.

Effects of vagal stimulation, atropine, and propranolol on fibrillation threshold of normal and ischemic ventricles

The effects of electrical stimulation of the vagus nerves and the administration of atropine on ventricular fibrillation threshold (VFT) were studied in open-chest hearts of 15 dogs anesthetized by alpha-chloralose. These studies were made in both normal and ischemic ventricles, i.e., before and during acute coronary occlusion. The ventricles were paces at a constant rate to eliminate rate-dependent changes and the minimal current required to induce ventricular fibrillation (or VFT) was determined by delivering a train of rapid rectanglular pulses (100 per second) to the venticle actoss the vulnerable period. In normal ventricles, VFT's were significantly increased by vagal stimulation (P less than 0.01) and decreased by atropine (P less than 0.05). Coronary occlusion markedly decreased VFT's (P less than 0.01), and vagal stimulation or atropine failed to alter VFT's significantly in these ischemic ventricles (P greater than 0.8). In additional 14 dogs, the effects of vagal stimulation and atropine were studied after the administration of propranolol. Propranolol alone increased VFT's significantly in boetreatment with propranolol, vagal stimulation and atropine failed to change VFT's significantly in both normal and ischemic ventricles (P greater than 0.8). These results indicate that the vagus nerves exert their effect on VFT by modifying the sympathetic nerve activity in normal ventricles, but such an effect is not significant enough to alter VFT in ischemic ventricles.

Facilitation of A-V nodal reciprocation by procainamide

Procainamide is known to depress conduction through the A-V node, and this property may facilitate the development of ventricular reciprocal beats or echoes. The occurrence of ventricular reciprocal beats was studied in 20 open-chest dogs before and after the administration of procainamide. While the ventricle was paced by basic stimuli, early ventricular premature beats were introduced at various coupling intervals to induce ventricular echoes. When ventricular echoes could be induced in a given heart, there was a continuous range of coupling intervals (or echo zone) within which ventricular echoes occurred. In the control state, no echo occurred in eight dogs and the echoes developed in 12 dogs with the mean echo zone of 38.3 msec. The effect of procainamide was studied at its therapeutic blood levels about 25 minutes after an intravenous injection of the drug in a dose of 10 mg. per kilogram. Of the first group of eight dogs, in which no echo occurred in the control state, four dogs developed ventricular echoes after the administration of procainamide with the mean echo zone of 29.3 msec. for the group. Of the second group of 12 dogs, in which ventricular echoes were induced in the control state, the administration of procainamide increased the echo zone in 10 dogs with the mean echo zone of 67.8 msec. for the group. Ventricular reciprocal beats were often sustained to produce short runs of supraventricular tachycardia in five dogs after the administration of procainamide. The results demonstrated a potentially deleterious effect of procainamide in facilitating the inducation of A-V nodal reciprocation by closely coupled ventricular premature beats.

Effect of acetylcholine on automaticity of canine Purkinje fibers

The effect of acetylcholine on automaticity of Purkinje fibers was studied in isolated canine false tendon preparations with conventional microelectrode techniques. Of 15 preparations with the control spontaneous rate of 12-60 beats/min, acetylcholine in a concentration of 0.5 mug/ml decreased the spontaneous rate by 20-87% in 13 preparations. This decrease in automaticity was due to a decrease in the slope of phase 4 depolarization and an increase in the maximum diastolic potential. The inhibitory effect of acetylcholine could be reversed by atropine in a concentration of 3 mug/ml in six preparations and prevented by pretreatment with atropine in another six preparations. Atropine per se did not have any appreciable effect on automaticity of Purkinje fibers. The results indicate that acetylcholine significantly suppresses automaticity of canine Purkinje fibers through its muscarinic action.

Effect of ventricular aberrancy on fibrillation threshold

VFT's were determined in 12 open-chest dogs at epicardial sites in the right and left ventricles (RV and LV) following normally or aberrantly conducted beats. The normal beats were produced by right atrial pacing, and the aberrant beats by surgical RBBB or ventricular pacing at an RV or LV site. The mean VFT following normal beats was 21.2 plus or minus 1.8 ma. in RV and 23.0 plus or minus 2.7 ma. in LV. The mean VFT following aberrant beats of RBBB was 21.3 plus or minus 2.6 ma. in RV and 25.0 plus or minus 2.8 ma. in LV. The difference between the mean VFT of normal beats and that of aberrant beats was not statistically significant. The mean values of VFT's determined in RV or LV following aberrant beats produced by pacing of the contralateral ventricle were not significantly different from those of the normal beats. The mean VFT was 22.9 plus or minus 3.1 ma. in RV and 20.1 plus or minus 2.1 ma. in LV. These results indicate that the aberrancy of ventricular beats per se is not associated with decreased VFT or increased ventricular vulnerability to fibrillation. The most predictable observation was that the mean VFT's were significantly lower in both ventricles when they were determined at the site of application of pacing stimuli. The mean values were 12.4 plus or minus 1.2 ma. in RV and 13.6 plus or minus 1.6 ma. in LV. This decrease in VFT may be due to slow conduction and increased asynchrony of recovery of excitability at or near the site of application of pacing stimuli.

Effects of unipolar cathodal and bipolar stimulation on vulnerability of ischemic ventricles to fibrillation

The effects of unipolar and bipolar stimulation on ventricular fibrillation threshold were studied during acute occlusion of the left anterior descending coronary artery in 13 anesthetized dogs. Values for ventricular fibrillation threshold were determined by delivering trains of rapid bipolar or unipolar pulses (100/sec) during the vulnerable period. The mean threshold value was found to be 13.0 ma for bipolar, 13.9 ma for unipolar anodal and 21.0 ma for unipolar cathodal stimulation. Ventricular fibrillation threshold was significantly lower (P less than 0.01) with both unipolar anodal and bipolar stimulation than with unipolar cathodal stimulation. In these animals, the first premature beats induced by the rapid stimuli occurred significantly earlier with unipolar anodal and bipolar stimulation than with unipolar cathodal stimulation. The effect of competition of unipolar or bipolar pacing stimuli with normally conducted ventricular beats was also studied in a group of 16 dogs. Repeated trials of competitive pacing during coronary occlusion showed that the incidence of ventricular fibrillation was significantly greater (P less 0.05) with bipolar pacing (36 percent) than with unipolar cathodal pacing (15 percent). These results indicate that bipolar pacing is potentially more dangerous than unipolar cathodal pacing and suggest that the incidence of pacemaker-induced ventricular fibrillation might be further reduced by the use of unipolar cathodal stimulation during acute myocardial infarction.