Novel role of the Ca(2+)-ATPase in NMDA-induced intracellular acidification

The mechanism involved in N-methyl-D-glucamine (NMDA)-induced Ca(2+)-dependent intracellular acidosis is not clear. In this study, we investigated in detail several possible mechanisms using cultured rat cerebellar granule cells and microfluorometry [fura 2-AM or 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein-AM]. When 100 microM NMDA or 40 mM KCl was added, a marked increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)) and a decrease in the intracellular pH were seen. Acidosis was completely prevented by the use of Ca(2+)-free medium or 1,2-bis(2-aminophenoxy)ethane-N,N,N', N'-tetraacetic acid-AM, suggesting that it resulted from an influx of extracellular Ca(2+). The following four mechanisms that could conceivably have been involved were excluded: 1) Ca(2+) displacement of intracellular H(+) from common binding sites; 2) activation of an acid loader or inhibition of acid extruders; 3) overproduction of CO(2) or lactate; and 4) collapse of the mitochondrial membrane potential due to Ca(2+) uptake, resulting in inhibition of cytosolic H(+) uptake. However, NMDA/KCl-induced acidosis was largely prevented by glycolytic inhibitors (iodoacetate or deoxyglucose in glucose-free medium) or by inhibitors of the Ca(2+)-ATPase (i.e., Ca(2+)/H(+) exchanger), including La(3+), orthovanadate, eosin B, or an extracellular pH of 8.5. Our results therefore suggest that Ca(2+)-ATPase is involved in NMDA-induced intracellular acidosis in granule cells. We also provide new evidence that NMDA-evoked intracellular acidosis probably serves as a negative feedback signal, probably with the acidification itself inhibiting the NMDA-induced [Ca(2+)](i) increase.

A method for identifying abrupt changes in U.S. cancer mortality trends

BACKGROUND

Summaries of trends in cancer rates evaluated over a fixed, short period are informative, but methods that evaluate trends over a longer time period, identifying when changes occur as well as the magnitude of the changes, can provide additional information.

METHODS

Cancer mortality trends from 1973-1995 were determined for more than 15 anatomic sites for white and black males and females using weighted piecewise linear regression analysis with a stepwise selection procedure. The dependent variable was the natural logarithm of the annual mortality rate, and the weight was the annual number of cancer deaths. The variability of estimated change points was examined by bootstrapping the residuals from the resulting models.

RESULTS

For black males, cancer mortality rates declined in the 1990s due to decreases in lung, esophageal, oral cavity, and prostate cancer rates. However, there was no significant decline for cancer of the colon and rectum. For white males, cancer mortality rates declined in the 1990s due to declines in cancer of the lung and colon/rectum since the mid-1980s and declines in prostate cancer in the 1990s. For black females and white females, total cancer mortality rates declined, but not significantly. Cancer rates for all sites except the lung declined significantly in the 1990s for white, but not black, females due to declining trends for carcinoma of the colon and rectum since the mid-1980s and for breast cancer in the 1990s.

CONCLUSIONS

A method for identifying major changes in cancer trends has been developed. Trends for cancer of the breast and colon/rectum indicate that gaps between rates for blacks and whites are widening.

Early metabolic inhibition-induced intracellular sodium and calcium increase in rat cerebellar granule cells

1. Possible mechanisms responsible for the increases in intracellular calcium ([Ca2+]i) and sodium ([Na+]i) levels seen during metabolic inhibition were investigated by continuous [Ca2+]i and [Na+]i measurement in cultured rat cerebellar granule cells. An initial small mitochondrial Ca2+ release was seen, followed by a large influx of extracellular Ca2+. A large influx of extracellular Na+ was also seen. 2. The large [Ca2+]i increase was not due to opening of voltage-dependent or voltage-independent calcium channels, activation of NMDA/non-NMDA channels, activation of the Na+i-Ca2+o exchanger, or inability of plasmalemmal Ca2+-ATPase to extrude, or mitochondria to take up, calcium. 3. The large [Na+]i increase was not due to activation of the TTX-sensitive Na+ channel, the Na+i-Ca2+o exchanger, the Na+-H+ exchanger, or the Na+-K+-2Cl- cotransporter, or an inability of Na+-K+-ATPase to extrude the intracellular sodium. 4. Phospholipase A2 (PLA2) activation may be involved in the large influx, since both were completely inhibited by PLA2 inhibitors. Moreover, melittin (a PLA2 activator) or lysophosphatidylcholine or arachidonic acid (both PLA2 activation products) caused similar responses. Inhibition of PLA2 activity may help prevent the influx of these ions that may result in serious brain injury and oedema during hypoxia/ischaemia.

Simple, reliable, and cost-effective yeast identification scheme for the clinical laboratory

The appearance of colonies on the chromogenic medium CHROMagar Candida combined with observation of morphology on corn meal-Tween 80 agar was used for the identification of 353 clinical yeast isolates. The results were compared with those obtained with API yeast identification kits. The accuracy of identification and the turnaround time were equivalent for each method, and our cultural method was less expensive.

The significance of CT scan or MRI in the evaluation of salivary gland tumors

Imaging modalities such as CT scan or MRI are frequently employed for the diagnosis of neoplastic lesions in the salivary glands. To evaluate the efficacy of the CT scan and the MRI in differentiating malignant neoplasm from benign lesions, 120 CT scans and 31 MRIs were retrospectively analyzed from 147 patients with salivary gland masses. All images were analyzed focusing on the presence of several relevant features. The pathologic results were matched with radiological features and also tabulated with radiological assessment. For the CT scans, the contour and margin of the lesion and tissue plane obliteration were found to be statistically significant indicators for malignant neoplasms. Among 69 CT scans interpreted as 'benign' by a radiologist, five cases (7%) were histologically diagnosed as 'malignant'. On the other hand, 20 out of 51 CT scans (39%) were misinterpreted as 'malignant'. For MRI, two out of 14 cases (14%) were radiologically misdiagnosed as 'benign' and six out of 17 patients (35%) as 'malignant'. In conclusion, whereas both the CT and MRI showed a similar level of accuracy in evaluation of salivary gland tumors, they showed a considerable tendency of misdiagnosis, especially by interpreting benign tumors as 'malignant'.

Practical design of a high-strength breast gradient coil

A high-strength three-axis local gradient coil set was constructed for MRI of the breast. Gradient fields with good uniformity (<10% deviation from the desired gradient) over most of the volume required for breast imaging were generated with efficiencies of up to 3.3 mT/m/A. The coils will allow diffusion breast imaging in clinically acceptable examination times. The electrical design, water cooling system, and fabrication techniques are described. Preliminary tests of the coil included images of a grid phantom and diffusion measurements in a short-T2 agarose gel phantom.

An expandable intravenous RF coil for arterial wall imaging

An intravenous (iv) radiofrequency (RF) coil is proposed as a means of obtaining high resolution images of artery wall. The anatomic positioning of peripheral artery/vein pairs was investigated and a phantom mimicking the iliac artery/vein pair was constructed. Imaging results, comparing iv coils with external coils, demonstrated a potential 15- to 20-fold increase in signal-to-noise ratio (SNR) with iv coils. The SNR benefit was measured over a cylindrical volume, adjacent to the coil, and typical of artery position. Prototype expandable iv coils were constructed of Cu-Be loops and introduced via an 8-Fr catheter. The effects of local and remote iv coil tuning were investigated and local tuning was found to provide significant SNR benefits. The in vivo performance of iv RF coils was demonstrated in a porcine animal model. The iv coils were found to be an excellent alternative to intraarterial coils.

Successful treatment of disseminated coccidioidomycosis with amphotericin B lipid complex

Coccidioidomycosis is endemic in regions of the Americas, but this infection may be encountered in travellers who return from an endemic region. A case is reported of a disseminated infection in a Hong Kong Chinese man, who was successfully treated with amphotericin B lipid complex (ABLC) after intolerance and toxicity precluded the use of other antifungal agents. Lipid-based formulations of amphotericin B merit further evaluation in the treatment of coccidioidomycosis and other systemic mycoses.

A survey on dental caries in schoolchildren on Lanyu Island

BACKGROUND

Lanyu Island has approximately 3000 inhabitants, mainly Yami aborigines. No survey of dental caries in schoolchildren has been done on this isolated island during the past decade. The purposes of this study were to investigate the prevalence of caries in schoolchildren on Lanyu and compare the results with the rest of Taiwan.

METHODS

A total of 289 schoolchildren (152 boys and 137 girls) aged 4 to 12 on Lanyu Island, were selected for this study. The dental examinations were done by 2 senior pediatric dentists using flashlight, dental mirrors and explorers during 4 days of examination. The survey included caries prevalence rate, restorative index, and mean scores for deft, DMFT, defs, and DMFS. Mean scores for carious teeth by type of surface and sex differences for deft and DMFT were also checked.

RESULTS

The results showed that Lanyu schoolchildren had a high caries prevalence rate (94.5%) and a low restorative index (5.75%). The mean scores of deft, DMFT, defs, and DMFS for all schoolchildren were 5.38 +/- 4.50, 1.67 +/- 2.22, 12.18 +/- 11.64, and 2.42 +/- 3.89, respectively. There were no significant sex differences in the overall mean scores of deft (p = 0.557) and DMFT (p = 0.151).

CONCLUSION

The data showed that the caries prevalence of Lanyu schoolchildren was as high as other Taiwanese schoolchildren. For the caries prevalence in deciduous teeth, the scores were even worse than the Taiwan average. This study will provide a baseline for future oral health policies on Lanyu Island.

Establishment and characterization of nine new head and neck cancer cell lines

We established new cell lines from head and neck cancer patients for studies of adhesion molecules and cellular behavior in nine patients with primary or metastatic cancer treated at the Asan Medical Center. Explant cultures of fresh tumor tissue were used to develop new permanent tumor cell lines. Lines were tested for tumor formation and histology in nude mice. Flow cytometry and indirect immunofluorescence were used to assess DNA content and expression of the alpha 6, beta 4, and beta 1 integrin subunits and the intercellular adhesion molecule 1 (ICAM-1). In vitro growth patterns and adhesion to plastic were assessed using phase contrast microscopy. AMC-HN-1 to -8 were derived from patients with squamous cell carcinoma. AMC-HN-9 was from an undifferentiated carcinoma of the parotid gland. The 8 lines we tested produced nude mouse tumors that are identical to the histology of the original tumors. AMC-HN-1, -2, -5, and -9 have epithelioid or spindle cell morphology with poor cell-to-cell and cell-to-substrate adhesiveness. AMC-HN-3, -4, -7, and -8 grow as adherent epithelioid monolayers. AMC-HN-6 exhibits multilayer stratification. Four lines are near diploid, 4 are hyperdiploid and 1 is hypodiploid. Only three express ICAM-1. All lines express the alpha 6, beta 4, and beta 1 integrin subunits but to different extent. Four, AMC-HN-1, -2, -5, and -6, express the beta 4 integrin at low levels, AMC-HN-3, -4, -7, and -9, have intermediate beta 4 expression, and AMC-HN-8 has extremely high beta 4 expression. The AMC-HN cell lines are representative in vitro models for the study of head and neck cancer biology. Our preliminary results indicate a close relationship between integrin expression and cell adhesion in vitro.

Aberrant cervical thymus: a case report and review of literature

This article illustrates a case of an aberrant cervical thymus presented as a neck mass. This is a case of a 4-month-old boy presenting with a right submandibular mass whose preoperative diagnosis was lymphangioma or neoplastic lesion. The mass was successfully removed and the histopathological examination showed normal thymic tissue with no diagnostic abnormality. This paper reviews the embryological background of aberrant cervical thymus, the varying clinical presentations with an emphasis on differential diagnosis, clinical work-up, and surgical treatment.

Use of CHROMagar Candida for genital specimens in the diagnostic laboratory

OBJECTIVE

To evaluate CHROMagar Candida (CA), a new yeast differential medium, for yeast isolation in a clinical laboratory for the routine examination of high vaginal swabs.

METHODS

Results of high vaginal swab cultures processed in a standard manner on plates containing equal halves of Sabouraud dextrose agar (SDA) and CA were compared. Non-Candida albicans yeast isolates were further speciated with API 20C AUX or API 32C. To assess the ease of use of CA, laboratory staff lacking in experience of the medium were asked to identify 23 unlabelled yeast cultures on CA by referring to six labelled reference plates.

RESULTS

Of the 1784 swab cultures processed, yeasts were isolated from 373 SDA and 368 CA. Of the 78 non-albicans isolates further speciated, CA identified correctly all cultures of C krusei and C tropicalis, and 82% of C glabrata. All the 38 inexperienced laboratory staff achieved 100% accuracy for C albicans and over 90% for C krusei and C tropicalis.

CONCLUSIONS

CA is a satisfactory isolation medium for genital specimens, allowing immediate and correct identification of the commonly encountered yeasts and easy recognition of mixed cultures.

Activation-dependent exposure of the inter-EGF sequence Leu83-Leu88 in factor Xa mediates ligand binding to effector cell protease receptor-1

Binding of factor Xa to human umbilical vein endothelial cells (HUVEC) is contributed by effector cell protease receptor-1 (EPR-1). The structural requirements of this recognition were investigated. Factor Xa or catalytically inactive 5-dimethylaminonaphthalene-1sulfonyl (dansyl) Glu-Gly-Arg-(DEGR)-chloromethylketone-factor Xa bound indistinguishably to HUVEC and EPR-1 transfectants, and inhibited equally well the binding of 125I-factor Xa to these cells. Similarly, factor Xa active site inhibitors TAP or NAP5 did not reduce ligand binding to EPR-1. A factor X peptide duplicating the inter-EGF sequence Leu83-Phe84-Thr85-Arg86-Lys87-Leu88- (Gly) inhibited factor V/Va-independent prothrombin activation by HUVEC and blocked binding of 125I-factor Xa to these cells in a dose-dependent manner (IC50 approximately 20-40 microM). In contrast, none of the other factor X peptides tested or a control peptide with the inter-EGF sequence in scrambled order was effective. A recombinant chimeric molecule expressing the factor X sequence Leu83-Leu88 within a factor IX backbone inhibited binding of 125I-factor Xa to HUVEC and EPR-1 transfectants in a dose-dependent fashion, while recombinant factor IX or plasma IXa had no effect. An antibody generated against the factor X peptide 83-88, and designated JC15, inhibited 125I-factor Xa binding to HUVEC. The JC15 antibody bound to factor Xa and the recombinant IX/X83-88 chimera in a concentration dependent manner, while no specific reactivity with factors X or IXa was observed. Furthermore, binding of 125I-factor Xa to immobilized JC15 was inhibited by molar excess of unlabeled factor Xa, but not by comparable concentrations of factors X or IXa. These findings identify the inter-EGF sequence Leu83-Leu88 in factor Xa as a novel recognition site for EPR-1, and suggest its potential role as a protease activation-dependent neo-epitope. This interacting motif may help elucidate the contribution of factor Xa to cellular assembly of coagulation and vascular injury.

Birth cohort and calendar period trends in breast cancer mortality in the United States and Canada

BACKGROUND

Previous studies of regional and temporal variation in U.S. breast cancer mortality rates have been confined largely to analyses of rates for white women.

PURPOSE

Breast cancer mortality rates from 1969 through 1992 for white women and black women in four regions of the United States and for all women throughout Canada were compared to identify racial, regional, and temporal differences. Differences and trends in the rates were evaluated in view of breast cancer risk factors and relevant medical interventions.

METHODS

Age-period-cohort models were fit to the data, and changes in birth cohort trends (suggesting a change in a breast cancer risk factor or protective factor) and calendar period trends (suggesting, in part, the impact of new or improved medical interventions) were examined.

RESULTS

Breast cancer mortality rates for white women were significantly higher in the Northeast than in any other region of the United States (two-sided t tests; P<.005); the rates for black women were not. Birth cohort trends for all women were similar until about 1940, with a moderation of mortality risk beginning around 1924. A marked moderation of risk by 4-year birth cohorts was observed for U.S. white women born after 1950, whereas stable or slightly decreasing trends were observed for U.S. black women and Canadian women. For women born from 1924 to around 1938, fertility rates increased for all three groups; after 1950, they declined uniformly. Looking at temporal effects, we found that the slope of the mortality calendar period trend increased in the 1980s compared with the 1970s for all women. In the last calendar period, 1991-1992, a trend of decreasing mortality rates was found for white women in the United States and for Canadian women.

IMPLICATIONS

Widespread environmental exposures are unlikely to explain the higher relative breast cancer mortality rates observed for U.S. white women in the Northeast, since the rates for black women in this region were not higher than in other regions. The moderation of breast cancer mortality rates for women born between 1924 and 1938 coincides with increased fertility rates following World War II. Stable or decreasing mortality rates for U.S. women and Canadian women born after 1950 were not expected in view of declining fertility rates, suggesting a change in a breast cancer risk factor or protective factor. The increase in calendar period trend slope in the 1980s likely reflects the coincident rise in breast cancer diagnosis via mammography. The recent decline in calendar period trend for white women in the United States and for Canadian women may be the result of earlier detection and increased use of adjuvant therapy.

Polyvinyl alcohol cryogel: an ideal phantom material for MR studies of arterial flow and elasticity

The authors present a unique application of polyvinyl alcohol (PVA) cryogel as an anthropomorphic, elastic, vascular phantom material that can be used in MR imaging. The composition consists of two nontoxic ingredients: water and PVA. The biomechanical and MR properties can be adjusted to be similar to those of excised porcine aortas by varying the number of freeze-thaw cycles to which the PVA solution is exposed. The authors present the T1, T2, shrinkage, and tensile properties of PVA cryogel tubes as a function of freeze-thaw cycles. MR images of a dual elastic aortic phantom undergoing pulsatile motion are shown.

Differential effects of vinblastine on polymerization and dynamics at opposite microtubule ends

We have characterized the effects of vinblastine on the growing and shortening dynamics at opposite ends of individual bovine brain microtubules at steady state in vitro by video microscopy. Vinblastine exerted strikingly different effects on the dynamics and polymer mass at the plus and minus ends of microtubules. At concentrations between 0.1 and 0.4 microM, the drug strongly depolymerized microtubules at minus ends, whereas it did not significantly depolymerize microtubules at plus ends. Vinblastine stabilized plus ends by suppressing the rate and extent of growth and shortening, decreasing the catastrophe frequency, and increasing the rescue frequency. In contrast, vinblastine destabilized minus ends by increasing the catastrophe frequency and decreasing the rescue frequency, whereas it had no effect on the rate or extent of growth or shortening. Thus, vinblastine moderately increased the overall dynamicity at minus ends while strongly suppressing dynamicity at plus ends. Both the kinetic destabilization of microtubules at minus ends and the stabilization at plus ends may contribute to the altered function of mitotic spindle microtubules of cells blocked in mitosis by low concentrations of vinblastine.

Temporal interferometric measurement of femtosecond spectral phase

Fourier spectral analysis of temporal interference resulting from beats between a reference optical frequency and a number of spectral components of a femtosecond optical pulse yields the spectral phase directly without the need for iterative calculations. A periodic multiple-slit mask placed in the Fourier plane of a femtosecond pulse shaper selects an ensemble of frequency components for measurement by cross correlation. An additional, out-of-period slit selects the reference frequency so that none of the desired beat tones overlaps redundant tones. We measure positive and negative cubic phase distortion introduced when the pulse shaper lens is tilted and the phase discontinuity of a 0-pi pulse (odd pulse) with a 13-slit mask. Finally, we demonstrate measurement of the spectral phase associated with true time delays with 17 slits.

Recent trends in U.S. breast cancer incidence, survival, and mortality rates

BACKGROUND

Clinical trials have demonstrated that use of mammographic screening and advances in therapy can improve prognosis for women with breast cancer.

PURPOSE

We determined the trends in breast cancer mortality rates, as well as incidence and survival rates by extent of disease at diagnosis, for white women in the United States and considered whether these trends are consistent with widespread use of such beneficial medical interventions.

METHODS

We examined mortality data from the National Center for Health Statistics and incidence and survival data by extent of disease from the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, all stratified by patient age, using statistical-regression techniques to determine changes in the slope of trends over time.

RESULTS

The age-adjusted breast cancer mortality rate for U.S. white females dropped 6.8% from 1989 through 1993. A significant decrease in the slope of the mortality trend of approximately 2% per year was observed in every decade of age from 40 to 79 years of age. Trends in incidence rates were also similar among these age groups: localized disease rates increased rapidly from 1982 through 1987 and stabilized or increased more slowly thereafter; regional disease rates decreased after 1987; and distant disease rates have remained level over the past 20 years. Three-year relative survival rates increased steadily and significantly for both localized and regional disease from 1980 through 1989 in all ages, with no evidence of an increase in slope in the late 1980s.

IMPLICATIONS

The decrease in the diagnosis of regional disease in the late 1980s in women over the age of 40 years likely reflects the increased use of mammography earlier in the 1980s. The increase in survival rates, particularly for regional disease, likely reflects improvements in systemic adjuvant therapy. Statistical modeling indicates that the recent drop in breast cancer mortality is too rapid to be explained only by the increased use of mammography; likewise, there has been no equivalent dramatic increase in survival rates that would implicate therapy alone. Thus, indications are that both are involved in the recent rapid decline in breast cancer mortality rates in the United States.

Improved MR images of arterial specimens by submersion in trichlorotrifluoroethane

MR images of ex vivo arterial specimens immersed in 1,1,2-trichloro-1,2,2-trifluoroethane (R-113) have improved signal-to-noise ratio and contrast-to-noise ratio. R-113 has no hydrogen atoms, so it yields no proton signal; hence, the contrast between the specimen and its background is maximized. SNR is maximized because (i) R-113 is nonconductive so that coil loading and inductive noise are minimized, and (ii) the volume susceptibility of R-113 closely matches that of water and tissue so that T2* effects are minimized. Short-term submersion of porcine aortas in R-113 was found to have no significant effect on the artery's hydration level, relaxation time, tensile strength, and structure or quantity of elastin, collagen, or smooth muscle cells.

Evaluation of birth cohort patterns in population disease rates

Interpretation of trends in disease rates using conventional age-period-cohort analyses is made difficult by the lack of a unique set of parameters specifying any given model. Because of difficulties inherent in age-period-cohort models, neither the magnitude nor the direction of a linear trend in birth cohort effects or calendar period effects can be determined unambiguously. This leads to considerable uncertainty in making inferences regarding disease etiology based on birth cohort or calendar period trends. In this paper, the authors demonstrate that changes in the direction or magnitude of long term trends can be identified unequivocally in age-period-cohort analyses, and they provide parametric methods for evaluating such changes in trend within the usual Poisson regression framework. Such changes can have important implications for disease etiology. This is demonstrated in applications of the proposed methods to the investigation of birth cohort trends in female breast cancer mortality rates obtained from the National Center for Health Statistics for the United States (1970-1989) and from the World Health Organization for Japan (1955-1979).

Colorectal cancer trends by race and anatomic subsites, 1975 to 1991

OBJECTIVES

To determine whether colorectal cancer rates among black men and women show the abrupt declines seen in whites since the mid-1980s and to determine how the cancer trends vary by anatomic subsites.

DATA SOURCES

Mortality data from the National Center for Health Statistics, Hyattsville, Md, and incidence and survival data from the Surveillance, Epidemiology, and End Results program of the National Cancer Institute, Bethesda, Md.

MAIN OUTCOME MEASURES

Trends in incidence, survival, and mortality rates.

RESULTS

For white men and women, cancer incidence rates declined for the right colon, left colon, and rectum after 1985. Stage-specific incidence rates for white men and women for each subsite had generally similar patterns. Distant-disease incidence rates declined beginning in the late 1970s, whereas regional-disease rates increased until the early to mid-1980s and then declined. An exception is the right colon in men, for which the incidence rates of distant disease did not decline, although the regional-disease pattern was similar to other sites. For blacks, colorectal cancer incidence rates changed little in the 1980s for men or women. In particular, there were no significant declines in the cancer incidence rates of the colorectum or of subsites after 1985. Black colorectal cancer mortality trends showed gender and age differences. Black men had significantly increasing colorectal cancer mortality rates from 1975 through 1992, but the increase after 1985 was observed only in men 65 years of age and older. The colorectal cancer mortality rates did not increase overall in black women in the 1980s, but the mortality rates increased slightly in women 65 years of age and older while declining in women younger than 65 years.

CONCLUSIONS

For whites, the trends in colorectal cancer rates by anatomic subsite support the contention that early-detection procedures, such as sigmoidoscopy and colonoscopy, are contributing to the declines in incidence and mortality rates since 1985. The absence in blacks of significant declines in colorectal incidence or mortality rates since 1985 suggests the need for a greater emphasis on early-detection programs in the black community, particularly for elderly blacks.

A novel transverse gradient coil design for high-resolution MR imaging

The authors describe a new gradient coil design for high resolution human, animal, specimen, or phantom imaging with high gradient efficiency and a large region of excellent gradient uniformity. Important features of our new design are the simple analytical description of the wire patterns that comprise the design, and ease of construction. Wires are spaced in a sinusoidal distribution around the circumference of the cylinder, and curved in an arcsin shape along the length of the cylinder. This coil produces a magnetic field pointing in a direction transverse to the axis of the coil with a gradient in the direction parallel to the axis of the coil. The same arcsin coil can be used to create a magnetic field pointing in a direction parallel to its axis with a gradient in a direction perpendicular to the coil axis. A prototype coil was constructed; field and inductance calculations were verified. Geometric variations on this coil design were modeled and their performance characteristics compared. This coil design is ideal for rapid implementation of a transverse gradient coil, since no specialized design software is required.

MR gradient coil heat dissipation

The temperature responses of five different gradient coil designs were modeled using simplified engineering equations and measured. The model predicts that the coil temperature approaches a maximum as an inverse exponential, where the maximum temperature is governed by two parameters: a local power density and a cooling term. The power density term is a function of position and is highest where the current paths have minimum widths and are closely packed. The cooling parameter consists of convective, conductive, and radiative components which can be controlled by (1) providing forced cooling, (2) having a coil former with high thermal conductivity and thin walls, and (3) varying the emissivity of the coil surfaces. For a given gradient strength, the average temperature rise is minimized by designing a coil with a small radius and thick copper. The model predicted the local temperature rise, which is also dependent on the current density, to within 5 degrees C of measured values.

Gastrointestinal bleeding due to whipworm (Trichuris trichiura) infestation: a case report

Severe whipworm infestation, an exceedingly uncommon cause of gastrointestinal bleeding, has not been reported in Taiwan. The reported case concerns a 59-year-old female who had suffered from abdominal pain and passage of tarry stool for several days. Esophagogastroduodenoscopy was performed, and several roundworms were seen in the second portion of duodenum. After removal, the characteristic appearance of Trichuris trichiura was apparent. After exploratory laparotomy for intractable bloody stool, the result of operative findings and pathological reports also confirmed our diagnosis. This is a case presented of massive gastrointestinal bleeding in which the cause of bleeding was diagnosed before operation to be whipworm infestation by endoscopic examination. The clinical and pathologic characteristics of the trichuriasis are described, with a brief review and discussion.

Direct measurement of the spectral phase of femtosecond pulses

We measure the spectral phase of femtosecond optical pulses using a time-frequency analog of Young's doubleslit interference. A pair of narrow slits in an opaque sheet selects two spectral frequencies from the femtosecond pulse spectrum in a zero-dispersion pulse stretcher. Measurement of the temporal phase of a family of beat frequencies obtained over a range of slit spacings yields the desired spectral phase directly. We demonstrate this technique by accurately measuring the quadratic phase added to 80-fs optical pulses by a 6.5-cm block of BK-7 glass.

A method for partitioning cancer mortality trends by factors associated with diagnosis: an application to female breast cancer

U.S. cancer mortality data derived from information recorded on death certificates are frequently relied upon as an indicator of progress against cancer. A limitation of this measure is the lack of information pertaining to the onset of disease, such as year-of-diagnosis, age-at-diagnosis, stage of disease at diagnosis and histology of lesions. However, population-based cancer registries collect these types of data and allow the calculation of an incidence-file based mortality rate. This incidence-based mortality rate allows a partitioning of mortality by variables associated with the cancer onset. Breast cancer incidence-based mortality measures are created and compared to mortality rates based on death certificates over a comparable time period. Novel mortality measures, such as mortality rates by stage-at-diagnosis, age-at-diagnosis and year-of-diagnosis, are used to illustrate the value of this approach.

Temporal patterns in colorectal cancer incidence, survival, and mortality from 1950 through 1990

BACKGROUND

Colorectal cancer mortality rates among U.S. white males remained relatively constant from 1950 through 1984 but declined sharply from 1985 through 1990. Those for U.S. white females decreased consistently from 1950 through 1984, with an acceleration of the decline from 1985 through 1990.

PURPOSE

A study was planned to investigate patterns in incidence, survival, and mortality rates over time in order to examine possible reasons for the gender difference in mortality trends and for the decrease in the slope of the mortality trends for both males and females in the late 1980s.

METHODS

Incidence and survival data from the Connecticut Cancer Registry were examined to investigate the gender differences in mortality rates from 1950 through 1984. Incidence and survival data from the Surveillance, Epidemiology, and End Results (SEER) Program were investigated to examine reasons for the abrupt downturn in mortality rates for both white males and white females beginning around 1985.

RESULTS

During the period 1950 through 1984, the colorectal cancer incidence rates in Connecticut increased for males and declined slightly for females. Survival rates were similar for both sexes, increasing on average over 1% per year for both females and males from 1950 through 1984. Examination of SEER data from 1975 through 1990 revealed that for both males and females there were 1) declines in overall incidence and mortality rates beginning in the mid-1980s, 2) steady declines in distant disease incidence rates since 1975, 3) increases in regional disease incidence rates until the early 1980s followed by declines in the late 1980s, and 4) increases in local disease incidence rates until the mid-1980s followed by declines in the late 1980s. Age-period-cohort analyses of mortality rates indicated a statistically significant moderation of colorectal cancer risk with both advancing birth cohorts and recent calendar periods.

CONCLUSIONS

The gender differences in colorectal cancer mortality rate trends observed from 1950 through 1984 are due to differences in incidence rate trends between males and females. Declining colorectal mortality rates in the late 1980s for males and females appear to reflect improved early detection. The peaking and subsequent decline of stage-specific incidence rates at later years for successively lower stage indicate sequential stage shifts as cancers are detected increasingly earlier over time. The increased use of sigmoidoscopy and fecal occult blood tests (triggering colonoscopy) appears to have played an important role in reducing colorectal cancer mortality. Improvements in birth cohort trends in risk for colorectal cancer for each sex suggest that lifestyle changes may have also contributed to the steady reductions in colorectal cancer mortality.

Survival advantage differences by age. Evaluation of the extended follow-up of the Breast Cancer Detection Demonstration Project

BACKGROUND

This study considers breast cancer survival patterns by age group among women diagnosed in the Breast Cancer Detection Demonstration Project (BCDDP) to provide insight into the nature of breast cancer and suggest a possible explanation as to why the results of the randomized clinical trials differ for women younger than 50 and those 50 or older. Based on the findings of several randomized clinical trials, there is a general consensus that breast cancer screening provides a significant benefit for women aged 50-69. From these trials, there is little evidence of a short term benefit and uncertainty regarding any long term benefit of mammographic screening for women aged 40-49.

METHODS

The BCDDP was not a randomized trial, but a nationwide breast cancer screening program conducted between 1973-1980, in which all participants received annual physical and mammographic examinations. Using the BCDDP data, this study calculated 14-year breast cancer survival among 4051 women diagnosed with breast cancer between 1973 and 1980 and followed through 1988 and 1989.

RESULTS

In all, 598 women died of breast cancer, resulting in an overall 14-year breast cancer survival of 83.4% (standard error = 0.007). Breast cancer survival varied by tumor type, lymph node status, tumor size, and stage at diagnosis. For most of the cases, however, both the distribution and breast cancer survival rates were similar for women aged 40-49, 50-59, and 60-69 across all prognostic indicators. Only breast cancer survival among women with invasive breast cancer who had a primary tumor 5 cm or larger or with positive lymph nodes differed by age, with women aged 60-69 at diagnosis having poorer survival. Analyses by modality of detection conducted in a subset of 2739 cases indicated that the 34.6% of the cases detected by mammography alone had the highest overall breast cancer survival rates (90.9%), while the 32.2% of the cases detectable by both physical examination and mammography had the lowest breast cancer survival (79.0%). Overall, women diagnosed with breast cancer in the BCDDP had a survival advantage if diagnosed with either a smaller tumor or no positive lymph nodes, or if their breast cancer was detected by mammography alone. For women with large tumors (> or = 5 cm), the survival was 80.8% for ages 40-49, 72.1% for ages 50-59, and 61.7% for ages 60-69.

DISCUSSION

Due to the higher breast cancer survival rates among women aged 40-49 with poorer prognostic characteristics, the breast cancer survival advantage for having a smaller tumor, no positive lymph nodes, or breast cancer detected by mammography alone was lower for women aged 40-49 than women aged 50 or older at diagnosis. These differences in survival advantage may help to account for the differences in mortality by age in the randomized clinical trials.

Cowden's disease: report of the first case in a Chinese

A 19-year-old Chinese female presenting mucocutaneous manifestations including facial trichilemmomas, oral papillomatosis, and acral keratosis was diagnosed, according to the criteria proposed by Salem and Steck, as a definite case of Cowden's disease, although no members of her family were affected. The cutaneous reticulohistiocytic granuloma and congenital nystagmus of eyes that occurred in this case were new combinations in the syndrome. To the best of our knowledge, this is the first documented case of Cowden's disease in a Chinese.

400-Hz mechanical scanning optical delay line

We have developed a simple, high-speed, nearly vibration-free, mechanically scanned, optical delay line suitable for femtosecond time-resolved signal-averaging measurements. We demonstrate a 2-ps time window autocorrelator with a display updated at 400 Hz. The delay line uses a dithering planar mirror as a time-varying linear phase ramp in the spectral plane of a modified grating-lens femtosecond pulse shaper. The time delay is linearly proportional to the angular deviation of the mirror. The high speed and low vibration are a result of the extremely small angular changes required to generate a large time delay.

A geometrically accurate vascular phantom for comparative studies of x-ray, ultrasound, and magnetic resonance vascular imaging: construction and geometrical verification

A technique for producing accurate models of vascular segments for use in experiments that assess vessel geometry and flow has been developed and evaluated. The models are compatible with x-ray, ultrasound, and magnetic resonance (MR) imaging systems. In this paper, a model of the human carotid artery bifurcation, is evaluated that has been built using this technique. The phantom consists of a thin-walled polyester-resin replica of the bifurcation through which a blood-mimicking fluid may be circulated. The phantom is surrounded by an agar tissue-mimicking material and a series of fiducial markers. The blood- and tissue-mimicking materials have x-ray, ultrasound, and MR properties similar to blood and tissue; fiducial markers provide a means of aligning images acquired by different modalities. The root-mean-square difference between the inner wall geometry of the constructed model and the desired dimensions was 0.33 mm. Static images were successfully acquired using x-ray, ultrasound, and MR imaging systems, and are free of significant artifacts. Flow images acquired with ultrasound and MR agree qualitatively with each other, and with previously published flow patterns. Volume-flow measurements obtained with ultrasound and MR were within 4.4% of the actual values.

Implications of birth cohort patterns in interpreting trends in breast cancer rates

BACKGROUND

Most investigations of trends in cancer rates are based on a cross-sectional approach, i.e., an examination of trends in rates by year of diagnosis or death. When there are longitudinal effects (i.e., trends in rates with successive birth cohorts), interpretation of cross-sectional trends can be misleading. Based on cross-sectional comparisons, U.S. breast cancer mortality rates have been reported to be decreasing over the last 20 years in younger women but to be increasing during the same period in older women.

PURPOSE

To examine the impact of longitudinal effects on the divergence of cross-sectional trends in breast cancer mortality with age, we examined breast cancer mortality rates from 1969 to 1988 by birth cohort for White women in the United States.

METHODS

By using a novel, nonparametric, permutational method to analyze 2-year, age-specific mortality rates for women aged 30-89 years, we identified trends in rates with successive birth cohorts.

RESULTS

The divergence in trends with age is shown to be consistent with an increase in breast cancer risk with successive birth cohorts from 1900 to 1916 and with a decrease in breast cancer risk with successive birth cohorts beginning around 1926.

CONCLUSION

Longitudinal effects have a significant impact on cross-sectional trends in breast cancer mortality.

IMPLICATIONS

Continuation of the birth cohort trend in younger women, which could correspond to changes in reproductive patterns accompanying the "baby boom," would result in decreasing cross-sectional trends in women 60-69 years of age over the next decade and in women 70-79 years of age in the subsequent decade. Longitudinal effects must be taken into consideration when monitoring and evaluating the effects of early detection, treatment, and intervention programs using national rates.

Pure rhabdomyosarcoma of the corpus uteri in a postpartum patient: report of a case and review of the literature

Pure rhabdomyosarcomas originate in the female genital tract. They are uncommon and most often occur in infancy or childhood as sarcoma botryoides (embryonal rhabdomyosarcoma) which involve the vagina and cervix. Such tumors rarely occur in adults. A pure rhabdomyosarcoma of the uterus that arose in a postpartum patient is described. The pertinent literature is discussed.

Staging patterns and early cancer detection

There is a great deal of indirect, nonexperimental evidence that a pattern of earlier-stage disease at diagnosis has a better outcome. Increased early detection activities can change, these stage patterns while various biases and the question of generalizability need to be kept in mind in their interpretation. The indirect evidences of possible benefit from early detection activities includes an increase in the number of cases detected, a pattern of more early- and less advanced-stage cases, an increase in the overall site-specific survival rate, and a decrease in the case fatality rate. Unless these intermediate markers are favorable, it is unlikely that early detection will reduce mortality. In addition, one should also differentiate a reduced incidence or a change in treatment as a cause for reduced mortality.

Analysis of the role of cancer prevention and control measures in reducing cancer mortality

One goal of the war against cancer is to create declines in cancer mortality rates. A decrease in these rates can only occur in two ways: 1) a decrease in incidence rates and 2) a real increase in overall survival rates. Reductions in incidence rates can be envisioned to occur through three mechanisms (in order of the time course of cancer): 1) reduction or amelioration of environmental or lifestyle risk factors, 2) use of agents that prevent the occurrence of cancer by blocking the progression to cancer, and 3) early detection at a preneoplastic state combined with treatment that prevents or delays progression to invasive cancer. "True" increases in overall survival can occur by two mechanisms (in order of the time course of cancer): 1) early detection of cancer by screening tests and subsequent effective treatment and 2) advancements in treatment. Unique patterns or "fingerprints" of stage-specific incidence and overall incidence and of survival rates characterize the various cancer prevention and control mechanisms that can decrease mortality rates. The rates are presented for five organ sites that have shown reduced cancer mortality. The patterns of rates for breast cancer for women under the age of 65 years were most consistent with early detection. The testicular cancer fingerprints were most consistent with advances in treatment, whereas cervical cancer rates were most consistent with the detection of preneoplastic lesions. The stomach cancer fingerprints were indicative of reductions in lifestyle or environmental risks, and colorectal cancer rates were indicative of a combination of treatment advances and early detection. These fingerprint patterns can be extended to other situations in which mortality trends are changing in order to suggest possible causes of observed changes. Limitations of this model are also discussed.

Analysis of the temporal patterns of benefits in the Health Insurance Plan of Greater New York trial by stage and age

Reductions in breast cancer mortality in the Health Insurance Plan of Greater New York trial are examined by age at entry and stage at diagnosis using a stage shift cancer screening model. The results indicate that for women aged 40-49 years at entry, benefits are associated with an internal stage shift of stage 1 cancers that have a prognosis poorer than the usual stage 1 cancers. Further, the results indicate that after 18 years of follow-up, of the reduction of 16 fewer deaths in the intervention group, 12-15 of the deaths are related to this internal shift. Given that stage 1 cases inherently have relatively good survival, the time required to see the screening benefit is substantial. For women aged 50-64 years at entry, the results suggest that benefits are associated primarily with shifts to or within stage 1. Further, the results indicate that after 6 years, of the reduction of 31 fewer deaths in the intervention group, 22 of the deaths are related to external shifts to stage 1. Given that stage 2 cancers have poorer survival than stage 1 cancers, screening benefit is seen sooner for the older cohort than for the younger cohort.

National survey of the pattern of care for carcinoma of the lung

A national survey of the patterns of care for carcinoma of the lung sponsored by the Commission on Cancer of the American College of Surgeons has documented continuing changes in epidemiology, treatment, and outcome. The project consisted of a long-term study of 15,219 patients whose diagnosis was made in 1981 and a short-term study of 19,074 patients whose diagnosis was made in 1986. The male/female incidence ratios have continued to decrease and the decrease has moved into the older age groups. Although the percentage of adenocarcinoma is increasing at the expense of squamous carcinoma, the latter is still the most prevalent histologic type. The accuracy of percutaneous needle biopsy and transbronchial biopsy of lung nodules reported from this group of 941 hospitals was high and equal to that reported by single institutions. The percentage of patients having a resection did not increase from 1981 to 1986, but for smaller lesions a move was apparent toward more lung-sparing resections. Little change has occurred in the use of adjuvant radiotherapy, particularly in stage III disease, where approximately 50% of the patients received postoperative irradiation. An improvement in the overall 5-year survival when compared with Surveillance, Epidemiology, and End Results data was noted. Whether this is a true improvement in survival or is the result of selection because of an unrecognized change in the pattern of care for patients with a carcinoma of the lung is unknown.

Estimating cancer mortality rates from SEER incidence and survival data

A method to estimate site-specific cancer mortality rates using Surveillance, Epidemiology, and End Results (SEER) Program incidence and survival data is proposed, calculated, and validated. This measure, the life table-derived mortality rate (LTM), is the sum of the product of the probability of being alive at the beginning of an interval times the probability of dying of the cancer of interest during the interval times the annual age-adjusted incidence rate for each year that data have been collected. When the LTM is compared to death certificate mortality rates (DCM) for organ sites with no known misclassification problems, the LTM was within 10 percent of the death certificate rates for 13 of 14 organ sites. In the sites that have problems with the death certificate rates, there were major disagreements between the LTM and DCM. The LTM was systematically lower than the DCM for sites if there was overreporting on the death certificates, and the LTM was higher than the DCM for sites if there was underreporting. The limitations and applications of the LTM are detailed.

Stage-shift cancer screening model

A stage-shift cancer screening model is developed in the context of a randomized controlled trial (RCT) of cancer screening. In the model, detection by screening causes the time of diagnosis of the cancer to be advanced so that either the stage at diagnosis is shifted from one stage to the next lower one or the stage of diagnosis is unchanged but the cancer is diagnosed earlier in the stage. These are called external and internal stage shifts, respectively. At each stage the extent of the external and internal shifts and any associated mortality benefits are estimated. Further, the model allows the interrelationships of these benefits within and between stages to be delineated. This then allows us to better understand the results of the RCT. Data from a completed breast cancer screening RCT are used to illustrate the application of the model and its value in improving our understanding of the trial's results.

Analysis of breast cancer mortality and stage distribution by age for the Health Insurance Plan clinical trial

The Health Insurance Plan (HIP) of Greater New York conducted a clinical trial to determine if screening for breast cancer with mammography and clinical examination would decrease breast cancer mortality. The extent of disease at diagnosis among breast cancers detected by screening and the effect of screening on breast cancer mortality have been evaluated in the cohort of all HIP women diagnosed with breast cancer within 6 years of entry into the trial and followed at least 18 years after trial entry. Six years was the earliest time at which the number of cases diagnosed in the control group was equal to the number of cases diagnosed in the study group. In the cohorts of women 40-49 and 50-64 years of age at entry, shifts were significant to lower stages for screen-detected cases. As a result, the study group women in each age cohort had significantly lower breast cancer mortality than control group women when statistical analyses were restricted to data from cases only. In the 40-49 age-at-entry cohort, the reduced breast cancer mortality in the study group appears to result from lower mortality in stage I cases as well as from earlier case detection, and this may explain differences between the two age-at-entry cohorts in the length of follow-up time required to demonstrate a mortality reduction due to screening.

Differentiating among proposed mechanisms for tumor promotion in mouse skin with the use of the multievent model for cancer

Numerous mechanisms for tumor promotion in mouse skin have been recently proposed. These include the multistage, genetic view of Slaga, Furstenberger, and Marks; the multistage, genetic and/or epigenetic view of Parkinson; and the two-stage view of Yuspa and Hennings. With the use of the multievent model, a mathematical model for cancer that can incorporate cell proliferation phenomena, these tumor promotion mechanisms were modeled mathematically. It was found that the models had different predictions about the incidence of papillomas in initiator-promoter-initiator experiments and the incidence of carcinomas in initiator-promoter experiments with varying periods of tumor promotion. Upon analysis, existing data were shown to be in agreement with the Yuspa and Hennings two-stage model. The analysis also supported the view, formulated by Scribner and co-workers, that different types of initiated cells were created, some capable of transformation to carcinomas and some not. Phenomena determined by use of benign tumors as the end point may need to be demonstrated with the use of the carcinoma as the end point, prior to the acceptance of these phenomena being applicable to the human carcinogenic process.

Use of multistage models to infer stage affected by carcinogenic exposure: example of lung cancer and cigarette smoking

Statistical methods based on the Armitage-Doll mathematical model of the carcinogenic process are presented for analyzing epidemiologic case-control studies of cancer. These methods are proposed to provide inferences regarding the stage(s) in the cancer process at which the exposure of interest acts. An example of these methods is given which shows evidence that carcinogens in cigarette smoke appear to affect the transition rates for two separate stages in the development of lung cancer, and the relative magnitudes of these effects are estimated. The data for this analysis came from a European multi-center case-control study of lung cancer. The results of the analysis show that: (1) the relative risk of lung cancer among continuing smokers compared to nonsmokers of the same age decreases as the age started smoking increases, while the rate of smoking stays fixed, a result which indicates a carcinogenic effect on an early stage in the process; and (2) the relative risk among ex-smokers compared to continuing smokers having the same duration and rate of smoking decreases with time since smoking stopped, a result which indicates a carcinogenic effect on a late stage in the process. Both results are shown to be best described by the hypothesis that cigarette smoking affects two stages. The estimated relative magnitudes of cigarettes' carcinogenic effects on the two stages indicate that the largest proportion of the total lifetime lung cancer risk among continuing smokers is due to its late stage effect, and that the proportion of risk due to causes other than smoking varies from 23% among men smoking 1-10 cigarettes per day to 6% among those smoking greater than 30 cigarettes per day. These findings imply that preventive measures directed toward inducing smokers to stop would have a potentially substantial payoff in reducing future lung cancer mortality.

A nonmathematical view of mathematical models for cancer

A qualitative view of mathematical models for cancer is presented. The Armitage and Doll multistage and Moolgavkar two-stage models of cancer are discussed in terms of their physical models. Time-related factors for these models as well as some of their characteristics are presented. The effect of age at first exposure, duration of exposure, time since last exposure and stage of carcinogenic effect on risk are detailed.

Coxsackievirus B4 infection of sympathetic ganglia in squirrel monkeys

Lumbar sympathetic ganglionitis was found by light microscopy in 2 of 17 (12%) squirrel monkeys (Saimiri sciureus) experimentally infected with Coxsackievirus B4. This finding shows that viruses can cause ganglionitis which, in turn, must cause autonomic nervous system dysfunction. Such viral ganglionitis may explain some diseases, including cardiovascular ones, of poorly understood or unknown etiology which present with manifestations of dysfunction of the sympathetic nervous system.