Hemorheological changes caused by lead exposure

Lead is a ubiquitous, biohazardous, and toxic heavy metal that induces a broad range of physiological, biochemical, and behavioral dysfunctions. We investigated the effect of lead on hemorheological characteristics, including deformability and aggregation. We found that red blood cell (RBC) deformability was unaffected at low concentrations of lead-rich plasma, but showed a significant decrease at high concentrations even within 1 h of incubation. In addition, apparent alterations in RBC aggregation were observed with an increase in lead concentration and incubation time. These results highlight the influence of lead on hemorheology and microcirculation.

Factors affecting unmet healthcare needs of older people in Korea

BACKGROUND

Despite the fact that the National Health Insurance programmes have ensured universal coverage for Koreans, disparities in access to health care and unmet healthcare needs still exist in Korea.

AIM

The purpose of this study was to analyse factors affecting unmet healthcare needs of older people in Korea.

METHODS

This study had a cross-sectional, descriptive design using secondary data taken from the Korean National Health and Nutrition Survey conducted in 2007-2009. A complex sampling design was used, and the participants included a nationally representative sample of 3943 people older than 64 years. Socio-demographic variables, subjective health, existence of chronic diseases, quality of life and unmet healthcare needs were included in the study instruments. Logistic regression analyses were performed in order to examine the relationship between unmet healthcare needs and independent variables.

RESULTS

According to the results, 29.4% of older women and 14.0% of older men had not visited clinics or hospitals when they needed to obtain healthcare services (unmet healthcare needs) during the past 12 months. Older women [odds ratio (OR) = 1.831, 95% confidence interval (CI) = 1.428-2.347] and those with poor subjective health (OR = 1.708, 95% CI = 1.371-2.126) and arthritis (OR = 1.278, 95% CI = 1.029-1.586) were more likely to have unmet healthcare needs than their counterparts.

CONCLUSIONS

Efforts to decrease unmet healthcare needs, targeting high-risk groups (especially for older women), are needed in order to prevent disability, decrease mortality and promote the quality of life of older people.

Treatment outcomes of 70 cases of early esophageal carcinoma: 12 years of experience

Early esophageal cancer (EEC) has an excellent prognosis compared to advanced esophageal cancer. Nowadays, endoscopic mucosal resection (EMR) may offer another alternative to cure early cancers of the gastrointestinal tract. We aimed to evaluate the clinical outcomes of EEC in Korea after curative treatments; EMR or surgery. We retrospectively reviewed the medical records of patients diagnosed as EEC from January 1994 to August 2005 at Yonsei University Medical Center, Seoul, Korea. Among 888 patients diagnosed with esophageal cancer, 70 (7.9%) were included as EEC. Among them, 10 patients (14.3%) were treated by EMR, and 50 (71.4%) by operation. The treatment outcomes of EEC in relation to various clinicopathologic factors along with survival rates were analyzed. There were 18 cases (30%) of mucosal lesions and 42 cases (70%) of submucosal lesions. Overall 5-year survival rate was 84.3%. When comparing treatment outcomes between EMR-treated and operated groups, there were no significant differences in complete remission (80%vs. 84%), recurrence (20%vs. 16%) and 5-year survival rate (100%vs. 78.3%). EEC is a potentially curable entity with a good clinical prognosis. EMR can be considered as another treatment arm for EEC, along with surgical resection.

K-ras activation generates an inflammatory response in lung tumors

Activating mutations in K-ras are one of the most common genetic alterations in human lung cancer. To dissect the role of K-ras activation in bronchial epithelial cells during lung tumorigenesis, we created a model of lung adenocarcinoma by generating a conditional mutant mouse with both Clara cell secretory protein (CC10)-Cre recombinase and the Lox-Stop-Lox K-ras(G12D) alleles. The activation of K-ras mutant allele in CC10 positive cells resulted in a progressive phenotype characterized by cellular atypia, adenoma and ultimately adenocarcinoma. Surprisingly, K-ras activation in the bronchiolar epithelium is associated with a robust inflammatory response characterized by an abundant infiltration of alveolar macrophages and neutrophils. These mice displayed early mortality in the setting of this pulmonary inflammatory response with a median survival of 8 weeks. Bronchoalveolar lavage fluid from these mutant mice contained the MIP-2, KC, MCP-1 and LIX chemokines that increased significantly with age. Cell lines derived from these tumors directly produced MIP-2, LIX and KC. This model demonstrates that K-ras activation in the lung induces the elaboration of inflammatory chemokines and provides an excellent means to further study the complex interactions between inflammatory cells, chemokines and tumor progression.

Prescription behaviours of office-based doctors to standardized common cold patients in Korea

PURPOSE

To investigate real pictures of prescription behaviours of office-based doctors in Korea, especially focusing on the prescription of oral antibiotics and injections.

METHODS

Prescription information was collected from 18 standardized patients (SPs) with the symptoms of the common cold who visited doctors' office.

RESULTS

For these patients antibiotics were prescribed by 96 doctors (64.7%) out of 148 and the rate of antibiotic prescription increased with age of doctors, increasing number of medicines, and cost of medicines. Analgesics were most frequently prescribed (91.8%), and gastrointestinal drugs (81.6%), antitussivies (61.2%), antithistamines (61.2%), decongestants (59.2%), mucolytics (51.0%) and proteolytic enzymes (32.7%) followed. More than half of the doctors intended to give injections to the patients, which was higher among internists and doctors prescribed more medicines.

CONCLUSIONS

Antibiotics and injections were frequently prescribed for mild common colds in Korea. Action to ensure judicious use of antibiotics and injection is urgent.

Analysis of vivax malaria cases in Gangwon-do (province), Korea in the year 2000

A total of 827 malaria cases were reported in the Gangwon-do in the year 2000. There were 18.2 cases per 100,000 inhabitants. There were 283 cases among civilians and 544 cases among the military. 90.6% of cases were reported in Cheorwon--(531), Hwacheon--(152), and Goseong--(66) gun (county), which bordered the demilitarized zone (DMZ). A distinct feature pertaining to the malaria cases in Gangwon-do is that the number of cases has increased about two times over the last year. The mean time from the beginning of symptoms to malaria diagnosis was five days. Control systems for malaria by public health organizations and military organizations are well maintained, but were not able to reduce the malaria prevalence rate. The cause for the increase in pattern of the malaria cases in Gangwon-do may be caused by the spreading of prevalent areas of malaria to the east. Continuous endeavor such as early detection of cases, early treatment, education on clinical symptoms and prevention of mosquito bites with repellent and mosquito nets will help to reduce the infection rate of malaria in Gangwon-do.

Is body mass index the prognostic factor in breast cancer?: a meta-analysis

This study was performed to integrate the results of previous studies that investigated the relationship between body mass index (BMI) and prognosis in breast cancer. We reviewed the English literatures using the MEDLINE database from 1966 to 1999. The materials included 12 published articles with a total of 8,029 cases of breast cancer. The effect size was obtained from hazard ratio in each study. Homogeneity test was conducted before the integration of each effect size and the result demonstrated that the studies were heterogeneous. A random effect model was used to integrate the overall effect size. The integrated effect size was 1.56 (95% confidence interval, 1.22-2.00). In addition, publication bias should be accounted for because each published study was asymmetric in shape revealed by funnel plot. These results suggest that BMI have a prognostic significance in breast cancer. We believe that well-designed longitudinal studies, involving a large number of samples are required to resolve these issues.

Meta-analysis of hypertension as a risk factor of cerebrovascular disorders in Koreans

This study was conducted to integrate the results of previous studies which evaluated hypertension as a risk factor for cerebrovascular disorders (CVD) in Koreans. We retrieved the Korean literature using a manual search and the English literature using the MEDLINE database concerning the relationship between hypertension and CVD in Koreans from 1980 to 1997. The overall effect size of hypertension as a risk factor of CVD was represented by common odds ratio (OR). Before the integration of each effect size, a heterogeneity test and a sensitivity test was conducted. The materials were nine published epidemiologic studies with a total of 2,271 cases of CVD. The common ORs (95% confidence interval) of overall CVD, hemorrhagic CVD and ischemic CVD associated with hypertension were 4.10 (3.56-4.71), 6.56 (4.92-8.80) and 3.28 (2.77-3.90), respectively. Thus, the common OR of hemorrhagic CVD associated with hypertension was significantly higher than that of overall or ischemic CVD. This suggests that hypertension is an important risk factor for overall CVD and its subtypes in Koreans. Due to the lack of reliable prospective studies, however, longitudinal study is required in this area.

An efficient cis-element discovery method using multiple sequence comparisons based on evolutionary relationships

The discovery of cis-element control motifs in noncoding DNA poses a difficult problem in genome analysis. Functional analysis by means of reporter constructs expressed in transgenic organisms is the most reliable method, but is by itself time-consuming and expensive. Searching noncoding DNA for known control motifs by sequence analysis is problematic, since protein binding motifs are short, in the range of 8-10 bp, and occur frequently by chance. Heretofore, the most reliable sequence analysis method has been the comparison of homologous sequence domains in related but moderately evolutionarily divergent species such as, for example, mouse and human. In such pairwise combinations, control regions are conserved because they serve a vital function and can be identified by their similar sequences. Single pairwise comparisons, however, allow the discovery of conserved sequence strings only at low resolution and without specific identity. We have investigated the possibility of using multiple sequence comparisons to correct these shortcomings. We applied this method to the Hoxc8 early enhancer region that has been previously analyzed in depth by functional methods and through its application successfully identified known protein binding cis-element motifs. Candidate protein binding sites could also be identified. This method, based on evolutionarily related sequence comparisons, should be quite useful as a prescreening step prior to functional analysis with corresponding savings in time and resources.

Interactions of disparate scales in drift-wave turbulence

Renormalized statistical theory is used to calculate the interactions between short scales (wave vector k) and long scales (wave vector q<<k) in the Hasegawa-Mima model of drift-wave turbulence (generalized to include proper nonadiabatic response for k( ||)=0 fluctuations). The calculations include the zonal-flow growth rate as a special case, but also describe long-wavelength fluctuations with q oriented at an arbitrary angle to the background gradient. The results are fully renormalized. They are subtly different from those of previous authors, in both mathematical form and physical interpretation. A term arising in previous treatments that is related to the propagation of short-scale wave packets is shown to be a higher-order effect that must consistently be neglected to lowest order in a systematic expansion in q/k. Rigorous functional methods are used to show that the long-wavelength growth rate gamma(q) is related to second-order functional variations of the short-wavelength energy and to derive a heuristic algorithm. The principal results are recovered from simple estimates involving the first-order wave-number distension rate gamma;((1))(k)equals, single dot abovek small middle dotnablaOmega;(k)/k(2), where Omega;(k) is a nonlinear random advection frequency. Fokker-Planck analysis involving gamma;((1))(k) is used to heuristically recover the evolution equation for the small scales, and a random-walk flux argument that relates gamma;((1))(k) to an effective autocorrelation time is used to give an independent calculation of gamma(q). Both the rigorous and heuristic derivations demonstrate that the results do not depend on, and cannot be derived from, properties of linear normal modes; they are intrinsically nonlinear. The importance of random-Galilean-invariant renormalization is stressed.

Functional plasticity in extrastriate visual cortex following neonatal visual cortex damage and monocular enucleation

Neonatal lesions of primary visual cortex (areas 17, 18 and 19; VC) in cats lead to significant changes in the organization of visual pathways, including severe retrograde degeneration of retinal ganglion cells of the X/beta class. Cells in posteromedial lateral suprasylvian (PMLS) cortex display plasticity in that they develop normal receptive-field properties despite these changes, but they do not acquire the response properties of striate neurons that were damaged (e.g., high spatial-frequency tuning, low contrast threshold). One possibility is that the loss of X-pathway information, which is thought to underlie striate cortical properties in normal animals, precludes the acquisition of these responses by cells in remaining brain areas following neonatal VC damage. Previously, we have shown that monocular enucleation at the time of VC lesion prevents the X-/beta-cell loss in the remaining eye. The purpose of the present study was to determine whether this sparing of retinal X-cells leads to the development of striate-like response properties in PMLS cortex. We recorded the responses of PMLS neurons to visual stimuli to assess spatial-frequency tuning, spatial resolution, and contrast threshold. Results indicated that some PMLS cells in animals with a neonatal VC lesion and monocular enucleation displayed a preference for higher spatial frequencies, had higher spatial resolution, and had lower contrast thresholds than PMLS cells in cats with VC lesion alone. Taken together, these results suggest that preserving X-pathway input during this critical period leads to the addition of some X-like properties to PMLS visual responses.

The accuracy of myocardial infarction diagnosis in medical insurance claims. Korean Research Group for Cardiovascular Disease Prevention and Control

We attempted to assess the accuracy of the International Classification of Diseases (ICD) codes for myocardial infarction (MI) in medical insurance claims, and to investigate the reasons for any inaccuracy. This study was designed as a preliminary study to establish a surveillance system for cardiovascular diseases in Korea. A sample of 258 male patients who were diagnosed with MI from 1993 to 1997 was selected from the Korea Medical Insurance Corporation cohort (KMIC cohort: 183,461 people). The registered medical record administrators were trained in the survey technique, and gathered data by investigating the medical records of the study subjects from March 1999 to May 1999. The definition of MI for this study included symptoms pursuant to the diagnostic criteria of chest pain, electrocardiogram (ECG) findings, cardiac enzyme and results of coronary angiography or nuclear scan. We asked the record administrators for the reasons of incorrectness for cases where the final diagnosis was 'not MI'. The accuracy rate of the ICD codes for MI in medical insurance claims was 76.0% (196 cases) of the study sample, and 3.9% (ten cases) of the medical records were not available due to hospital closures, non-computerization or missing information. Nineteen cases (7.4%) were classified as insufficient due to insufficient records of chest pain, ECG findings, or cardiac enzymes. The major reason of inaccuracy in the disease code for MI in medical insurance claims was 'to meet the review criteria of medical insurance benefits (45.5%)'. The department responsible for the inaccuracy was the department of inspection for medical insurance benefit of the hospitals.

Putative chromosomal deletions on 9P, 9Q and 22Q occur preferentially in malignant gastrointestinal stromal tumors

To characterize the type of genetic alterations in gastrointestinal stromal tumors (GISTs), we performed a comprehensive allelotype study of 14 GISTs (2 benign, 7 borderline and 5 malignant) by polymerase-chain-reaction and loss-of-heterozygosity (PCR-LOH) analysis using 102 microsatellite markers, and compared the results with comparative-genomic-hybridization (CGH) analysis. Among the 38 evaluated chromosomal arms, 16 (42.1%) showed LOH in at least one patient. Most frequent LOH was observed at chromosome 14p and 14q (9/14, 64%) and this was demonstrated in all types of GISTs (50% in benign, 71% in borderline and 80% in malignant). Additional chromosomal deletions were found in several chromosomal arms. Among them, deletions on chromosomal arms of 22q (3/14, 21.4%), 9p (2/14, 14.3%) and 9q (2/14, 14.3%) were the most frequent, and were detected only in malignant GISTs both by PCR-LOH and by CGH analysis. Additionally, 2 malignant GISTs with LOH on 9p showed homozygous deletions in the restricted area of 9p by multiplex PCR-LOH analysis. Thus, several putative chromosomal changes were preferentially present in malignant GISTs but rare in benign and borderline GISTs. These findings suggest that accumulated chromosomal changes may contribute to the progression and/or malignant transformation of GISTs.

Putative chromosomal deletions on 9P, 9Q and 22Q occur preferentially in malignant gastrointestinal stromal tumors

To characterize the type of genetic alterations in gastrointestinal stromal tumors (GISTs), we performed a comprehensive allelotype study of 14 GISTs (2 benign, 7 borderline and 5 malignant) by polymerase-chain-reaction and loss-of-heterozygosity (PCR-LOH) analysis using 102 microsatellite markers, and compared the results with comparative-genomic-hybridization (CGH) analysis. Among the 38 evaluated chromosomal arms, 16 (42.1%) showed LOH in at least one patient. Most frequent LOH was observed at chromosome 14p and 14q (9/14, 64%) and this was demonstrated in all types of GISTs (50% in benign, 71% in borderline and 80% in malignant). Additional chromosomal deletions were found in several chromosomal arms. Among them, deletions on chromosomal arms of 22q (3/14, 21.4%), 9p (2/14, 14.3%) and 9q (2/14, 14.3%) were the most frequent, and were detected only in malignant GISTs both by PCR-LOH and by CGH analysis. Additionally, 2 malignant GISTs with LOH on 9p showed homozygous deletions in the restricted area of 9p by multiplex PCR-LOH analysis. Thus, several putative chromosomal changes were preferentially present in malignant GISTs but rare in benign and borderline GISTs. These findings suggest that accumulated chromosomal changes may contribute to the progression and/or malignant transformation of GISTs.

Hox cluster genomics in the horn shark, Heterodontus francisci

Reconstructing the evolutionary history of Hox cluster origins will lead to insights into the developmental and evolutionary significance of Hox gene clusters in vertebrate phylogeny and to their role in the origins of various vertebrate body plans. We have isolated two Hox clusters from the horn shark, Heterodontus francisci. These have been sequenced and compared with one another and with other chordate Hox clusters. The results show that one of the horn shark clusters (HoxM) is orthologous to the mammalian HoxA cluster and shows a structural similarity to the amphioxus cluster, whereas the other shark cluster (HoxN) is orthologous to the mammalian HoxD cluster based on cluster organization and a comparison with noncoding and Hox gene-coding sequences. The persistence of an identifiable HoxA cluster over an 800-million-year divergence time demonstrates that the Hox gene clusters are highly integrated and structured genetic entities. The data presented herein identify many noncoding sequence motifs conserved over 800 million years that may function as genetic control motifs essential to the developmental process.

VEP and PERG acuity in anesthetized young adult rhesus monkeys

This study used the swept spatial-frequency method to compare retinal and cortical acuity in anesthetized young adult rhesus monkeys. Visual evoked potentials (VEPs) and pattern electroretinographic responses (PERGs) were recorded from 25 monkeys (age range: 4-12 years) anesthetized with a continuous infusion of propofol. The stimuli were temporally countermodulated sine-wave gratings that increased in spatial frequency within a 10.24-s period. All animals were refracted using acuity estimated from the zero micro-volt intercept of the linear regression of evoked potential amplitude on spatial frequency. Average sweep acuities were 23.7 cycles/deg +/- 1.5 S.E.M. and 23.1 cycles/deg +/- 1.8 S.E.M. for the PERG and VEP, respectively. VEP and PERG acuities were within the range expected based on acuities estimated from behavioral studies in macaques. PERG and VEP acuities were highly correlated (r = 0.90) and equally sensitive to spherical blur. On a subset of animals, test-retest reliability of animals, and interocular correlations, were high (r = 0.87 and r = 0.83, respectively). Increasing propofol dosage 8-fold did not degrade PERG or VEP acuity. This study demonstrates that high spatial-frequency acuities can be rapidly obtained from young adult rhesus monkeys under a wide dose range of propofol anesthesia using the swept spatial-frequency method.

Evolution of chordate hox gene clusters

In this article, we consider the role of the Hox genes in chordate and vertebrate evolution from the viewpoints of molecular and developmental evolution. Models of Hox cluster duplication are considered with emphasis on a threefold duplication model. We also show that cluster duplication is consistent with a semiconservative model of duplication, where following duplication, one daughter cluster remains unmodified, while the other diverges and assumes a new architecture and presumably new functions. Evidence is reviewed, suggesting that Hox gene enhancers have played an important role in body plan evolution. Finally, we contrast the invertebrates and vertebrates in terms of genome and Hox cluster duplication which are present in the latter, but not the former. We question whether gene duplication has been important in vertebrates for the introduction of novel features such as limbs, a urogenital system, and specialized neuromuscular interactions.

Anthropometric and biomechanical characteristics on body segments of Koreans

This paper documents the physical measurements of the Korean population in order to construct a data base for ergonomic design. The dimension, volume, density, mass, and center of mass of Koreans whose ages range from 7 to 49 were investigated. Sixty-five male subjects and sixty-nine female subjects participated. Eight body segments (head with neck, trunk, thigh, shank, foot, upper arm, forearm and hand) were directly measured with a Martin-type anthropometer, and the immersion method was adopted to measure the volume of body segments. After this, densities were computed by the density equations in Drillis and Contini (1966). The reaction board method was employed for the measurement of the center of mass. Obtained data were compared with the results in the literature. The results in this paper showed different features on body segment parameters comparing with the results in the literature. The constructed data base can be applied to statistical guideline for product design, workspace design, design of clothing and tools, furniture design and construction of biomechanical models for Korean. Also, they can be extended to the application areas for Mongolian.

Pesticide poisoning and its related factors among Korean farmers

This study has been carried out to assess the health damages due to pesticide use and its related risk factors among Korean farmers. Data regarding pesticide handling and poisoning symptoms were collected by means of a questionnaire filled in by 1,032 farmers from two provinces. The results showed that during summer farming 21.9% of the subjects experienced suspected pesticide poisoning. 18.8% mild poisoning, and 2% more serious poisoning. Univariate and logistic regression analyses between "no poisoning", including the "suspected poisoning" and "poisoning" groups, were performed to select significant variables related to pesticide poisoning. Four variables were significantly associated: sex, days of consecutive pesticide use, hours of pesticide use per day, having received safety education (weakly associated), and compliance with safety guidelines for application. Safety education was weakly associated with poisoning, while age, education, wearing protective gear, and compliance with safety guidelines for personal hygiene after pesticide use were not significant risk factors to determine pesticide poisoning.

Clinicopathologic characteristics of mucinous gastric adenocarcinoma

There has been considerable controversy over the prognosis of mucinous gastric adenocarcinoma (MGC). In this study we analyzed the clinicopathologic differences between MGC and non-mucinous gastric carcinoma (NMGC). In addition, the relationship between mucin content and other clinicopathologic variables, including prognosis in MGC, was also investigated. We reviewed 2118 patients with pathologically-confirmed gastric cancer who underwent gastrectomy at the Department of Surgery, Yonsei University College of Medicine, during the period between Jan. 1987 and Dec. 1993. Among them, 130 patients had gastric carcinoma with extracellular mucin (MGC) and 1988 patients had gastric carcinoma without extracellular mucin (NMGC). We placed the MGC patients into two groups according to mucin content: mucin content involving over 50% of the tumor (dominant type, n = 94) and mucin content involving less than 50% of the tumor area (partial type, n = 36). The results were as follows: MGC was more common in males than NMGC. The size of the tumor in MGC (mean 5.3 cm) was larger than that of NMGC (mean 4.4 cm). The patients with MGC had a higher incidence of Borrmann type IV (MGC: 16.1%, NMGC: 9.9%), more frequent serosal invasion (MGC: 75.4%, NMGC: 48.6%), lymph-node metastasis (MGC: 75.4%, NMGC: 50.7%), and peritoneal metastasis (MGC: 10.0%, NMGC: 3.5%) than patients with NMGC. The patients with MGC were more advanced in stage at the time of diagnosis and had a worse overall 10-year survival rate (44.9%) than patients with NMGC (54.7%). However, the 10-year survival rate according to the stage of MGC was similar to that of NMGC. There were no significant differences between the mucin content and other pathologic variables, including prognosis, i.e. similar biologic behavior between dominant type MGC and partial type MGC. In conclusion, we suggest that MGC was more frequently diagnosed in advanced stage than NMGC with a poorer prognosis and that it is reasonable to consider the carcinoma with mucin content involving more than 30% of the tumor area as MGC.

Comparative studies on mammalian Hoxc8 early enhancer sequence reveal a baleen whale-specific deletion of a cis-acting element

Variations in regulatory regions of developmental control genes have been implicated in the divergence of axial morphologies. To find potentially significant changes in cis-regulatory regions, we compared nucleotide sequences and activities of mammalian Hoxc8 early enhancers. The nucleotide sequence of the early enhancer region is extremely conserved among mammalian clades, with five previously described cis-acting elements, A-E, being invariant. However, a 4-bp deletion within element C of the Hoxc8 early enhancer sequence is observed in baleen whales. When assayed in transgenic mouse embryos, a baleen whale enhancer (unlike other mammalian enhancers) directs expression of the reporter gene to more posterior regions of the neural tube but fails to direct expression to posterior mesoderm. We suggest that regulation of Hoxc8 in baleen whales differs from other mammalian species and may be associated with variation in axial morphology.

Primary malignant melanoma of the esophagus

Primary malignant melanoma of the esophagus is exceedingly rare. The existence of primary malignant melanoma in the esophagus had been in doubt until the presence of benign melanocytes was demonstrated within the esophagus. Hematogenous and lymphatic metastases are common. The prognosis is poor even after a radical procedure due to early metastasis. We report here two cases of primary malignant melanoma of the esophagus. One is a melanotic melanoma and the other is an amelanotic melanoma.

Percutaneous transmyocardial revascularization

Transmyocardial revascularization (TMR) is a potential therapy for patients with severe angina pectoris and coronary anatomy deemed unsuitable for traditional revascularization techniques. Investigations of TMR are reviewed with emphasis on studies relevant to the development of a percutaneous, catheter-based transmyocardial revascularization procedure (PMR). The results of the preliminary animal studies and description of the PMR procedure are discussed. The recently initiated human PMR protocol is summarized and possible future investigative directions are outlined.

Retrospective comparison of infusional 5-fluorouracil, doxorubicin, and mitomycin-C (modified FAM) combination chemotherapy versus palliative therapy in treatment of advanced gastric cancer

About one-third of patients with gastric cancer are unresectable at the time of diagnosis. Their median survival is < 6 months, with a grave prognosis. The purpose of this study was to assess the efficacy of a modified FAM (mFAM) regimen in advanced gastric cancer. We retrospectively reviewed the clinical records of 409 advanced gastric cancer patients who had not received curative surgery. Among 409 patients, 202 patients were treated with an mFAM regimen (infusional 5-FU + doxorubocin + mitomycin-C), and 207 patients received no chemotherapy (control group). No differences were found in clinical parameters between the two groups. The 1-year survival rates were 34.1% for the mFAM-treated group and 22.5% for the control group (p = 0.0135). In subset analysis, a higher 1-year survival rate was demonstrated in patients with mFAM and palliative surgery. Of the 154 evaluable patients in the mFAM-treated group, the response rate was 17.5%. In these patients, median response duration was 30 weeks, and progression-free survival was 23 weeks. Overall toxicity of mFAM regimen was relatively tolerable and reversible. In conclusion, FAM combination chemotherapy, which has been used as a standard therapy, prolonged survival after modification of the administration schedule and combination with palliative surgery. A prospective randomized study is warranted to confirm this conclusion from our retrospective study.

Percutaneous method of laser transmyocardial revascularization

Laser transmyocardial revascularization (TMR) creates conduits from the left ventricular cavity into the myocardium and has been forwarded as a potential method of perfusing ischemic myocardium. The procedure typically employs a CO2 laser to produce transmyocardial channels from the epicardial to the endocardial surface via an open thoracotomy. Preliminary studies in animals and human subjects have yielded promising results, and clinical trials evaluating the long-term efficacy of the procedure are in progress. We now report the use of a percutaneous method of TMR using a laser delivered through a novel catheter system. To assess the feasibility of performing percutaneous TMR, studies were performed on 15 adult canine subjects utilizing a holmium:YAG laser. Via a femoral artery approach, novel laser catheters were introduced into the left ventricular cavity under fluoroscopic guidance. Biplane coronary angiography, ventriculography, and transesophageal echocardiography were employed to direct catheters to specific regions and assess the efficacy of creating transmyocardial channels. Multiple channels could be created in the anterior, lateral, inferoposterior, and septal regions as demonstrated by contrast ventriculography with confirmation by subsequent gross and histologic examination. The procedure was tolerated well without any ventricular dysfunction or sustained ventricular arrhythmias. We have demonstrated that laser transmyocardial revascularization via a percutaneous approach is feasible with creation of channels from the endocardial surface of the left ventricle into the myocardium. On gross and histological examination, these channels are similar in appearance to those created by the currently employed open chest, epicardial method of TMR.

Effects of aging on numbers and sizes of neurons in histochemically defined subregions of monkey striate cortex

BACKGROUND

In addition to its horizontal layers, primate striate cortex has a vertical modular organization. Among the vertical modules are histochemically defined areas of high and low cytochrome oxidase labeling in the supragranular layers, referred to, respectively, as blobs and interblobs. Cytochrome c oxidase (CO) blobs and interblobs differ in their inputs from the magnocellular and parvocellular visual pathways, their physiological properties, and many aspects of their neurochemistry. The present study investigated whether aging differentially affects neuron numbers or sizes in the supragranular blobs or interblobs.

METHODS

The right hemisphere from three young adult (5.2-12.4 years) and four old (24.0-26.7 years) rhesus monkeys was used. Tangential sections through the central visual-field representation were stained for CO and counterstained with cresyl violet. Montages were constructed through cortical layers 2 and 3, and neuron counts and size measurements were made in blob and interblob regions using stereological procedures that yield unbiased estimates. Blob density also was calculated.

RESULTS

CO blob density was 3.76/mm2 in young adults and 3.95/mm2 in old animals, a difference that was not statistically significant. Neuron soma sizes also did not differ significantly between young adult and old animals or between blob and interblob regions. In addition, neuron density was not significantly different between young adult and old animals. However, independent of age, neuron density was significantly higher in the center of interblobs (394,058 cells/mm3) than in the center of blobs (333,638/mm3).

CONCLUSIONS

Our results and those of previous studies (Vincent et al. 1989. Anat. Rec. 223:329-341; Peters and Sethares. 1993. Anat. Rec. 236:721-729) suggest that aging has little or no effect on the densities or sizes of the different functional or morphological types of neurons that exist in the different cortical layers or in the different vertical modules marked by CO blobs and interblobs. These findings are consistent with the results of our previous anatomical and physiological studies of the rhesus monkey retina and lateral geniculate nucleus. These results suggest that the retinogenic-ulostriate pathways are relatively unaffected by aging in the rhesus monkey.

Phylogenetic relationships of annelids, molluscs, and arthropods evidenced from molecules and morphology

Annelids and arthropods have long been considered each other's closest relatives, as evidenced by similarities in their segmented body plans. An alternative view, more recently advocated by investigators who have examined partial 18S ribosomal RNA data, proposes that annelids, molluscs, and certain other minor phyla with trochophore larva stages share a more recent common ancestor with one another than any do with arthropods. The two hypotheses are mutually exclusive in explaining spiralian relationships. Cladistic analysis of morphological data does not reveal phylogentic relationships among major spiralian taxa but does suggest monophyly for both the annelids and molluscs. Distance and maximum-likelihood analyses of 18S rRNA gene sequences from major spiralian taxa suggest a sister relationship between annelids and molluscs and provide a clear resolution within the major groups of the spiralians. The parsimonious tree based on molecular data, however, indicates a sister relationship of the Annelida and Bivalvia, and an earlier divergence of the Gastropoda than the Annelida-Bivalvia clade. To test further hypotheses on the phylogenetic relationships among annelids, molluscs, and arthropods, and the ingroup relationships within the major spiralian taxa, we combine the molecular and morphological data sets and subject the combined data matrix to parsimony analysis. The resulting tree suggests that the molluscs and annelids form a monophyletic lineage and unites the molluscan taxa to a monophyletic group. Therefore, the result supports the Eutrochozoa hypothesis and the monophyly of molluscs, and indicates early acquisition of segmented body plans in arthropods.

Accuracy of biplane and multiplane transesophageal echocardiography in diagnosis of typical acute aortic dissection and intramural hematoma

OBJECTIVES

The purpose of this study was to evaluate the diagnostic accuracy of biplane and multiplane transesophageal echocardiography in patients with suspected aortic dissection, including intramural hematoma.

BACKGROUND

Transesophageal echocardiography is a useful technique for rapid bedside evaluation of patients with suspected acute aortic dissection. The sensitivity of transesophageal echocardiography is high, but the diagnostic accuracy of biplane and multiplane transesophageal echocardiography for dissection and intramural hematoma is less well defined.

METHODS

We studied 112 consecutive patients at a major referral center who had undergone biplane or multiplane transesophageal echocardiography to identify aortic dissection. The presence, absence and type of aortic dissection (type A or B, typical dissection or intramural hematoma) were confirmed by operation or autopsy in 60 patients and by other imaging techniques in all. The accuracy of transesophageal echocardiography for ancillary findings of aortic dissection (intimal flap, fenestration and thrombosis) was assessed in the 60 patients with available surgical data.

RESULTS

Of the 112 patients, aortic dissection was present in 49 (44%); 10 of these had intramural hematoma (5 with and 5 without involvement of the ascending aorta). Of the remaining 63 patients without dissection, 33 (29%) had aortic aneurysm and 30 (27%) had neither dissection nor aneurysm. The overall sensitivity and specificity of transesophageal echocardiography for the presence of dissection were 98% and 95%, respectively. The specificity for type A and type B dissection was 97% and 99%, respectively. The sensitivity and specificity for intramural hematoma was 90% and 99%, respectively. The accuracy of transesophageal echocardiography for diagnosis of acute significant aortic regurgitation and pericardial tamponade was 100%.

CONCLUSIONS

Biplane and multiplane transesophageal echocardiography are highly accurate for prospective identification of the presence and site of aortic dissection, its ancillary findings and major complications in a large series of patients with varied aortic pathology. Intramural hematoma carries a high complication rate and should be treated identically with aortic dissection.

Effects of aging on the densities, numbers, and sizes of retinal ganglion cells in rhesus monkey

We used sterological procedures that yield unbiased estimates to quantify the densities, numbers, and soma sizes of retinal ganglion cells in seven young adult and six old rhesus monkeys. The retinae were flat mounted so that we could determine whether there are different aging-related losses in different retinal regions. The mean (+/-standard deviation) total number of ganglion cells was 1,529,039 +/- 115,260 in young-adult retinae and 1,556,698 +/- 165,056 in old retinae, a difference that was not statistically significant. There also were no significant differences between young and old retinae in the densities or total numbers of ganglion cells in the four retinal quadrants, in four concentric retinal zones from fovea to peripheral retina, or in smaller hemiretinal regions of the concentric zones. Ganglion-cell soma sizes also did not differ significantly between young and old animals. Moreover, counts of the largest ganglion cells, which probably correspond to P alpha ganglion cells, revealed no selective loss of these cells with aging. These results are consistent with our previous anatomical and physiological studies of the LGN. Together they suggest that the retino-geniculate pathways are relatively unaffected by aging in the rhesus monkey.

Differentiation of alpha coma from awake alpha by nonlinear dynamics of electroencephalography

The electroencephalogram, as a probe of scalp-recorded electrical activity arising from the human cortex, provides useful information because of its temporal and spatial organization. Recent developments in nonlinear dynamics suggest that an object can be constructed in an n-dimensional space out of a temporal sequence of data such as an EEG signal and that its organization is characterized by the dimensionality of the object (in this case, human brain activity). We have carried out an analysis of a set of alpha coma EEG patterns in comparison to the awake alpha EEG patterns of normal volunteers and patients. Alpha coma recorded from a single channel is visually indistinguishable from normal resting alpha due to its similar frequency spectrum (a broad-band spectrum with 1/f characteristics). Our results show that alpha coma dimensionality, however, differs from that of normal alpha in that it has a greater variability over different temporal segments of EEG. Single channel recordings in 7 patients with alpha coma were differentiable from those of 10 subjects with "normal" EEGs. Through dynamic analysis of the EEG, novel methods of signal extraction from EEG may become evident and applicable to clinical practice.

Relationship between numbers of retinal ganglion cells and lateral geniculate neurons in the rhesus monkey

Studies of the numbers of retinal ganglion cells and lateral geniculate nucleus (LGN) neurons in primates suggest that the numbers of both types of neurons may vary over a two-fold range from one individual to another. This raises the question of whether the numbers of ganglion cells and LGN neurons are related or vary independently from individual to individual. We used stereological procedures to obtain unbiased estimates of the numbers of both cell types in seven rhesus monkeys. We found no significant correlation (rs = -0.21) between the numbers of retinal and LGN cells in the same animals. In agreement with previous studies, the average ratio of the number of retinal ganglion cells that project to the LGN and the number of LGN cells was approximately 1:1. However, this ratio varied over a two-fold range, from 0.78:1 to 1.64:1, in individual animals. These results have important implications for understanding the mechanisms of retino-geniculate development and for understanding the connectional wiring between the retina and LGN.

Long-term follow-up of gracilis muscle transposition in children

Sixteen children of uncontrollable fecal incontinence have been treated with Pickrell's gracilis muscle transposition since 1983: 12 had an imperforate anuses with multiple corrective operative procedures and 4 had traumatic destructions of anal sphincters. We report a series of 11 cases whom we followed-up over a period of 0.8 to 10.5 years (mean; 5.6 years). Seven patients were evaluated by anorectal manometry. All patients except one who had left hemipelvectomy and permanent colostomy showed nearly normal continence during the follow-up period. There was no evidence of fibrosis in the transposed muscles and the tensions of the transposed muscles were well maintained. The voluntary contractions of the transposed muscles were well maintained and efficient in all cases. The general manometric parameters did not correlate well with the functional results; however, there was a strong correlation in the S/R ratio (maximum squeeze pressure/resting pressure) with the functional results. We believe that the good functional outcome of this procedure need not only the meticulous surgical technique but also the personal motivation and the compliance with physiotherapy. In conclusion, although the gracilis muscle transposition never results in normal continence, acceptable continence can be achieved in the selected patients.

Transhiatal gastric transposition of a long gap esophageal atresia

Transhiatal gastric transposition was performed in a long gap esophageal atresia without tracheoesophageal fistula. The patient was a 12 months old female infant with previous stamm-type gastrostomy. The stomach was mobilized preserving the right gastric artery, the right gastroepiploic artery and spleen. The proximal and distal blind pouches of esophagus were excised by transcervical and transhiatal route, respectively. The mobilized stomach was pulled up into the neck through esophageal hiatus and posterior mediastinal route. The esophagogastrostomy, the only one anastomosis of this procedure, was safely performed in the neck. There were neither anastomotic leak nor early anastomotic stricture. The oral feeding was quickly established. There was no clinical evidence of regurgitation, difficulty of gastric emptying, hoarseness or respiratory problem. The low morbidity combined with satisfactory functional result indicates that the transhiatal gastric transposition is a safe and easy alternative surgical procedure for esophageal replacement in long gap esophageal atresia.

Influence of the superior colliculus on responses of lateral geniculate neurons in the cat

The superior colliculus (SC) projects to all layers of the cat's lateral geniculate nucleus (LGN) and thus is in a position to influence information transmission through the LGN. We investigated the function of the tecto-geniculate pathway by studying the responses of cat LGN neurons before, during, and after inactivating the SC with microinjections of lidocaine. The LGN cells were stimulated with drifting sine-wave gratings that varied in spatial frequency and contrast. Among 71 LGN neurons that were studied, 53 showed a statistically significant change in response during SC inactivation. Control experiments with mock injections indicated that some changes could be attributed to slow waxing and waning of responsiveness over time. However, this could not account for all of the effects of SC inactivation that were observed. Forty cells showed changes that were attributed to the removal of tecto-geniculate influences. About equal numbers of cells showed increases (22 cells) and decreases (18 cells) in some aspect of their response to visual stimuli during SC inactivation. The proportion of cells that showed tecto-geniculate influences was somewhat higher in the C layers (68% of the cells) than in the A layers (44% of the cells). In addition, among cells that showed a significant change in maximal response to visual stimulation, the change was larger for cells in the C layers (64% average change) than in the A layers (26% average change) and it was larger for W cells (61% average change) than for X and Y cells (29% average change). Nearly all of the X cells that showed changes had an increase in response, and nearly all of the Y cells had a decrease in response. In addition, across all cell classes, 80% of the cells with receptive fields < 15 deg from the area centralis had an increase in response, and 80% of the cells with receptive fields > or = 15 deg from the area centralis had a decrease in response. None of the LGN cells had significant changes in spatial resolution, and only three cells had changes in optimal spatial frequency. Ten cells had a change in contrast threshold, 25 cells had a change in contrast gain, and 29 cells had a change in the maximal response to a high-contrast stimulus. Thus, our results suggest that the tecto-geniculate pathway has little or no effect on spatial processing by LGN neurons. Rather, the major influence is on maximal response levels and the relationship between response and stimulus contrast.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of aging on the primate visual system: spatial and temporal processing by lateral geniculate neurons in young adult and old rhesus monkeys

1. Visual abilities decline during normal aging, and many of these declines are due to neural changes in the retina or central visual pathways. We have begun studies of the primate visual system to investigate the location and nature of these changes as well as to answer general questions about the effects of aging on neural function. We began with the dorsal lateral geniculate nucleus (LGN) because it is the main structure through which visual information passes on the way to cortex and because the parallel parvocellular and magnocellular pathways, which may be affected differently by aging, are anatomically distinct there. 2. Single-cell recordings were made in the LGN of young adult (5-16 yr) and old (25-28 yr) rhesus monkeys. We made quantitative measures of a wide variety of response properties for a large number of parvocellular (n = 257) and magnocellular (n = 113) neurons in the two groups of animals. As a result, in addition to studying the effects of aging, we were able to make quantitative comparisons between parvocellular and magnocellular neurons using larger samples than have been studied previously and for some properties that have not been studied before. 3. We found that magnocellular neurons have significantly higher maximal response rates and signal-to-noise ratios than parvocellular neurons. However, response latencies to visual stimulation were similar for neurons in the two types of layers. In agreement with previous studies, magnocellular neurons had higher maximal contrast sensitivity and higher contrast gain than parvocellular neurons. However, the sensitivity difference occurred because nearly all of the neurons with low sensitivities (< 10) were in the parvocellular layers, not because neurons in the magnocellular layers had the highest sensitivities. 4. Neurons with the smallest receptive-field centers, the highest spatial-frequency resolutions, and the highest optimal spatial frequencies were found in the parvocellular layers. However, the overall distributions of each of these properties overlapped substantially for neurons in the two types of layers, and the mean values were not significantly different. The mean high temporal-frequency cutoff was significantly higher for magnocellular than parvocellular neurons, but the difference was small (only 3 Hz), and it occurred because many parvocellular neurons had lower cutoffs than any seen in the magnocellular layers, not because magnocellular neurons had the highest temporal-frequency cutoffs. Parvocellular neurons also had narrower temporal-frequency tuning than magnocellular neurons. However, there was no significant difference in optimal temporal frequency.(ABSTRACT TRUNCATED AT 400 WORDS)

Foveal flicker sensitivity in healthy aging eyes. II. Cross-sectional aging trends from 18 through 77 years of age

Foveal flicker contrast sensitivity was measured for healthy adults at temporal frequencies from 2.5 to 50 Hz. The first experiment compared two-interval forced-choice (2IFC) and yes-no detection (Y-N) testing procedures for younger (19-33-year-old) and older (67-73-year-old) observers. The 2IFC technique resulted in higher absolute estimates of sensitivity. However, within a method, relative differences were similar. Therefore the two methods gave similar estimates of temporal contrast-sensitivity change with age. Experiment 2 compared 89 observers from 18 through 77 years of age to explore the effect of the time course of aging on flicker sensitivity. The 2IFC procedure was used, and retinal illuminance changes with age were controlled. Significant overall losses in contrast sensitivity were found for the 45-54, 55-64, and 65-77-year-old age groups. Overall sensitivities for the 35-44-year-old group were comparable with or (not significantly) higher than those for the 18-24- and 25-34-year-old groups. The results suggested that (1) foveal temporal contrast sensitivity does not decline until after 44 years, (2) losses after 44 years are in amplitude but not in temporal resolution of the visual response, and (3) the mean rate of loss is approximately 0.78 decilog per decade after 44 years. These results are consistent with the existence of three phases of development of temporal contrast sensitivity over the life span. The results also emphasize the importance of including healthy-eyed age-matched controls in studies of flicker sensitivity in visual dysfunctions that affect mainly older adults.

Roux-en-Y end-to-side esophagojejunostomy with stapler after total gastrectomy

One hundred gastric cancer patients who underwent total gastrectomy and Roux-en-Y, end-to-side esophagojejunostomy by using stapling devices were analyzed with regard to their operative results. The median time required for the anastomosis was 18 minutes (range of 15 to 45 minutes). A cartridge of 25 mm in diameter was preferred (85% of 25 mm vs. 15% of 28 mm). In 92 patients, procedures were uneventful. Intraoperative problems happened in 8 patients: Two misfirings of stapler due to mechanical problems, in 6 patients, doughnut tissues were incomplete. Mechanical problems were solved by a change of the stapler and for incomplete doughnut tissues, anastomosis was simply reinforced (2 cases) or reanastomosed with restaplings (4 cases). Anastomotic leakage occurred in 2 patients but it was seen only in radiological studies. During the follow up period, two cases of anastomotic stricture were found and they were treated with endoscopic dilatations. There was no operative mortality nor other complication. In addition, routine use of the Levin tube after total gastrectomy was appraised by comparing postoperative courses. Twenty patients were randomly divided into two groups; for 10 patients the Levin tube was removed at the recovery room and for another 10 patients the Levin tube was indwelled until peristalsis returned. Timing of the tube removal did not affect the duration of the hospital stay and starting day of oral intake. We think that the stapler, when properly used, can facilitate the esophagojejunostomy safely and routine use of the Levin tube after total gastrectomy may be unnecessary.

Mid-frequency loss of foveal flicker sensitivity in early stages of age-related maculopathy

Temporal contrast sensitivity in eyes at risk for exudative age-related maculopathy (ARM) was compared to that in age-matched healthy older eyes. The test stimulus was a foveally viewed, flickering, long-wavelength 2.8 degrees diameter circle in an equiluminant (photopic) surround. Retinal illuminance and decision criterion differences were experimentally controlled. Eyes in the healthy and ARM-risk groups had 20/30 or better Snellen acuity and intraocular pressure of less than 22 mmHg. Nevertheless, the ARM-risk patients were less sensitive to flicker contrast, especially for mid-temporal frequencies. This suggests that flicker sensitivity may be useful in identifying patients at risk for exudative ARM. In addition, comparison with other research reveals a paradox: Mid-temporal frequency sensitivity losses may be attributable primarily to a "high temporal frequency" mechanism.

Foveal flicker sensitivity discriminates ARM-risk from healthy eyes

The "good" eyes of 13 patients with monocular exudative ARM were compared with age-matched healthy eyes of 19 subjects. Membership in the two study groups was based upon careful clinical evaluation of the tested eye as well as upon status of the fellow eye. We asked whether temporal contrast sensitivity for a long-wavelength, low spatial frequency stimulus can be used to identify the group in which a given eye belongs. Using step-wise discriminant analysis, we found that the ARM-risk and healthy eyes could be classified with 78% accuracy on the basis of foveal flicker sensitivity at two temporal frequencies--14 and 10 Hz (in order of estimated weight.)

Preliminary evaluation of flicker sensitivity as a predictive test for exudative age-related maculopathy

Flicker contrast sensitivity was tested in the "good" eyes of 13 patients with monocular exudative age-related maculopathy (ARM). The stimulus was a foveal, long-wavelength, low spatial frequency 2.8 degrees circle in an equiluminant (photopic) surround. Two of these ARM-risk eyes have since developed exudative ARM. Compared to healthy age-matched eyes, the two eyes that developed exudative ARM had significantly lower sensitivity at 10-40 Hz up to 9 mo before exudative symptoms appeared. The implications of these results regarding the time-course of ARM and the predictive value of foveal contrast sensitivity testing are considered. Based upon data and theoretical considerations, the authors speculate that sensitivity loss between 10 and 40 Hz is a good predictor of which eyes will develop exudative ARM. This proposal will be tested by new data from current as well as new ARM-risk subjects.