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Biomedical subjects

L Goldstein

Publications and source records attributed to L Goldstein.

At least 91 records · Page 5Linked to original sources
PubMed1993

Mammography adherence and psychological distress among women at risk for breast cancer.

BACKGROUND: Previous studies estimate that first-degree relatives of women with breast cancer have a twofold to 10-fold increased risk of developing breast cancer. Recently, attention has focused on the mammography screening practices of women who are at high risk for breast cancer. PURPOSE: Our purpose was to characterize mammography screening practices in a sample of first-degree relatives of breast cancer patients and to identify variables that may serve as barriers to or facilitators of adherence to mammography. METHODS: Cross-sectional (rather than prospective) data were collected by telephone interviews with 140 women aged 35-79 years who had a family history of breast cancer in at least one first-degree relative (mother, sister, or daughter). Data were recorded on mammography screening patterns, depression, stress impact, and breast cancer worries. RESULTS: Women whose mammography history adhered to age-specific recommendations varied by age: 76% of first-degree relatives aged 35-39 years, 86% aged 40-49 years, and 63% aged 50 years or more. In bivariate analyses, level of education (P = .001), employment (P = .046), and time since diagnosis of the index patient (P = .044) were significantly and positively associated with mammography adherence. Variables associated negatively with adherence included age (P = .019), intrusive thoughts about breast cancer (P = .042), and breast cancer worries that interfered with daily functioning (P = .004). Multivariate analysis by logistic regression indicated that only breast cancer worries (odds ratio [OR] = 2.5; 95% confidence interval [CI] = 1.09-5.9) and education (OR = 4.8; CI = 1.6-14.3) were significant independent predictors of mammography adherence. CONCLUSIONS: This study suggests that most women at high risk for breast cancer adhere to the recommended mammography screening guidelines of the National Cancer Institute. However, rates of adherence among high-risk women aged 50 years and older are suboptimal; only 63% of these women received annual screening mammograms, and 13% had never been screened. Breast cancer worries may pose a barrier to mammography adherence among high-risk women, particularly those with less formal education. IMPLICATIONS: Prospective longitudinal studies are needed to validate the present findings and to evaluate the impact of psychoeducational interventions for women with affected first-degree relatives.

Adult↗
PubMed1993

Markov chain modelling of bioassay toxicity procedures.

Many bioassay procedures to test a new substance for toxicity, like some phase I clinical trials, can be modelled as first-order Markov chains with absorbing states. We provide a general framework for such procedures. We show how one may calculate under any dose response curve assumption final absorption probabilities, and a number of total average costs such as time required until trial completion, number of subjects treated, number of subjects exhibiting unacceptable levels of toxicity, and amount of medication administered. One may use the above information associated with the trial for an a priori comparison between competing designs under consideration. We provide an example of such a comparison.

Biological Assay↗
PubMed1993

Volume-regulatory amino acid transport in erythrocytes of the little skate, Raja erinacea.

Skate erythrocytes swell in a hypotonic medium and then reduce their volume mainly by releasing the beta-amino acids taurine and beta-alanine. Although these amino acids exhibit a net efflux, Na(+)-independent influx is also increased. Both the reduction in cell volume and increase in amino acid transport are inhibited by several inhibitors of band 3-mediated anion transport, including 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) [L. Goldstein and S. R. Brill, Am. J. Physiol. 260 (Regulatory Integrative Comp. Physiol. 29): R1014-R1020, 1991]. The objective of the present investigation was to further characterize the mechanism of volume-activated amino acid transport. Na(+)-independent amino acid uptake was studied because of the ease in controlling amino acid concentrations. Na(+)-independent taurine uptake was observed to be linear over a range of 0.1-15 mM and was not inhibited by 10 mM beta-alanine, suggesting that the transporter may be a channel rather than a carrier. The uptake of a variety of amino acids was examined to characterize the size of the putative channel. Glycine, beta-alanine, taurine, proline, gamma-aminobutyric acid (GABA), and threonine exhibited volume-activated transport that was DIDS inhibited, whereas aspartic acid, leucine, methionine, and ornithine were not transported. On the basis of the size of these amino acids, it appears that molecules containing eight or fewer major atoms and having a molecular mass of < 125-131 Da are transported during volume activation but larger molecules are not. We estimate the size of the channel to be 5.7-6.3 A in diameter.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1992

A potentially critical Hpa II site of the X chromosome-linked PGK1 gene is unmethylated prior to the onset of meiosis of human oogenic cells.

Hpa II site H8 is in the CpG-rich 5' untranslated region of the human X chromosome-linked gene for phosphoglycerate kinase 1 (PGK1). It is the only Hpa II site in the CpG "island" whose methylation pattern is perfectly correlated with transcriptional silence of this gene. We measured DNA methylation at site H8 in fetal oogonia and oocytes and found, using a quantitative assay based on the polymerase chain reaction, that purified germ cells isolated by micromanipulation were unmethylated in 47-day to 110-day fetuses, whereas ovaries depleted of germ cells and non-ovary tissues were methylated. We conclude that site H8 is unmethylated in germ cells prior to the onset of meiosis and reactivation of the X chromosome.

Base Sequence↗
PubMed1992

Poisson, compound Poisson and process approximations for testing statistical significance in sequence comparisons.

DNA and protein sequence comparisons are performed by a number of computational algorithms. Most of these algorithms search for the alignment of two sequences that optimizes some alignment score. It is an important problem to assess the statistical significance of a given score. In this paper we use newly developed methods for Poisson approximation to derive estimates of the statistical significance of k-word matches on a diagonal of a sequence comparison. We require at least q of the k letters of the words to match where 0 less than q less than or equal to k. The distribution of the number of matches on a diagonal is approximated as well as the distribution of the order statistics of the sizes of clumps of matches on the diagonal. These methods provide an easily computed approximation of the distribution of the longest exact matching word between sequences. The methods are validated using comparisons of vertebrate and E. coli protein sequences. In addition, we compare two HLA class II transplantation antigens by this method and contrast the results with a dynamic programming approach. Several open problems are outlined in the last section.

Algorithms↗
PubMed1992

Auditory magnetic source localization in twins.

We recorded magnetoencephalographic (MEG) auditory evoked fields (EF) from the L and R hemispheres of 12 paris of twins, 6 monozygotic (MZ), and 6 dizygotic (DZ) and localized the source of the 100 msec latency EF component termed the M100. M100 sources exhibited greater similarity in location in MZ twin pairs, especially in the L hemisphere. These findings support the hypothesis that the functional location of processing of nonmeaningful unattended auditory stimuli may depend more heavily on left hemisphere structures. Furthermore, genetic effects are evident in these left hemisphere structures and their activity, as is a substantial amount of environmental variance.

Acoustic Stimulation↗
PubMed1992

The interrelation between sclerosing cholangitis and ulcerative colitis in patients undergoing liver transplantation.

Thirty-six patients underwent orthotopic liver transplantation (OLT) for primary sclerosing cholangitis under cyclosporine, azathioprine, and steroid immunosuppression. Of these patients, 29 suffered from chronic ulcerative colitis. The purpose of this study is to determine (1) whether replacement of the diseased liver and the altered immunocompetence suppresses the manifestation of chronic ulcerative colitis, and (2) if active colonic disease alters allograft function. Thirty of 36 patients survived OLT. After OLT, seven of 14 patients with symptomatic colon disease at the time of transplantation continue to suffer from active chronic ulcerative colitis, and three of 13 who were asymptomatic developed clinically active disease. Intractable colonic disease was the indication for post-OLT proctocolectomy in three patients, and one refused an indicated colectomy. Despite the long duration of the disease, none developed colonic malignancy. Long-term graft assessment showed good hepatocyte synthetic function in patients suffering from either active or inactive disease. Liver alkaline phosphatase, however, was significantly higher in patients suffering from active colonic disease. Furthermore, the alkaline phosphatase in symptomatic patients was higher than that seen in a matched cohort undergoing OLT for chronic active hepatitis or primary biliary cirrhosis. These results suggest that (1) liver replacement and immunosuppression in patients suffering from sclerosing cholangitis and ulcerative colitis do not alter the course of the colon disease, and (2) active chronic ulcerative colitis does not adversely affect allograft function, although elevation of alkaline phosphatase may be the harbinger of recurrence over the long term.

Adult↗
PubMed1992

Articulatory phonology: an overview.

An overview of the basic ideas of articulatory phonology is presented, along with selected examples of phonological patterning for which the approach seems to provide a particularly insightful account. In articulatory phonology, the basic units of phonological contrast are gestures, which are also abstract characterizations of articulatory events, each with an intrinsic time or duration. Utterances are modeled as organized patterns (constellations) of gestures, in which gestural units may overlap in time. The phonological structures defined in this way provide a set of articulatorily based natural classes. Moreover, the patterns of overlapping organization can be used to specify important aspects of the phonological structure of particular languages, and to account, in a coherent and general way, for a variety of different types of phonological variation. Such variation includes allophonic variation and fluent speech alternations, as well as 'coarticulation' and speech errors. Finally, it is suggested that the gestural approach clarifies our understanding of phonological development, by positing that prelinguistic units of action are harnessed into (gestural) phonological structures through differentiation and coordination.

Female↗
PubMed1992

[A case of direct right pulmonary artery-left atrium fistula].

An unusual case of cyanotic heart disease in a 20-year-old male has been presented. Cyanosis was due to right to left shunt through direct right pulmonary artery--left atrium fistula. After successful operative ligation of the fistula, the patient got rid of cyanosis and is doing well.

Abnormalities, Multiple↗
PubMed1992

[Anatomical correction of transposition of the great arteries in 7 newborn infants].

In the presented article, the course and results of anatomical correction of transposition of great arteries (TGA) in 7 neonates (2 females and 5 males) with mean body mass of 3250 g and 2 to 5 days old (mean 3 days) are reviewed. Surgery was performed in moderate hypothermia. St. Thomas cold cardioplegia was used. Mean aortic clamping time was 70 min (55-115), and the time of extracorporeal circulation was 165 min (117-210). Low cardiac output in all patients in the postoperative period required prolonged mechanical ventilation and positive inotropic drugs. Out of 7 patients operated, two died (29%). The cause of death in both cases was myocardial ischemia of right ventricle. The other 5 patients were discharged after healing of operational wound. In the control echocardiographic examination performed 3 to 12 months postoperatively, apart from one case of moderate pulmonary artery stenosis, no other haemodynamically significant complications were noted.

Coronary Vessel Anomalies↗
PubMed1991

Inhibition by monochloramine of the transport of glutamine and glucose in HeLa cells and lymphocytes.

1. Chloramine was previously shown to inhibit glutamine uptake by human lymphoblast tumour cells. In the present study, the effect of monochloramine on the glutamine and glucose transport systems in HeLa cells and rat mesenteric lymphocytes was investigated. 2. Initial exposure to monochloramine slightly inhibited both the glutamine and glucose transport systems in HeLa cells. However, pre-exposing the cells to monochloramine increased its inhibitory action. 3. Similar results were obtained using rat mesenteric lymphocytes, which suggests that monochloramine's effects are not cell specific. 4. Only the Na(+)-independent (system L) component of glutamine transport activity in HeLa cells was inhibited by monochloramine. 5. Dithiothreitol protected both the glucose and glutamine transport carriers in HeLa cells against monochloramine inhibition. 6. Monochloramine did not inhibit HeLa cell metabolism, nor enhance cell lysis, which, in conjunction with other experimental data, suggests that monochloramine inhibits cellular transport activity by binding to thiol groups present on the membrane.

3-O-Methylglucose↗
PubMed1991

Magnetic auditory M100 source location in normal females.

We recorded magnetoencephalographic auditory evoked fields from the left and right hemispheres of six normal adult female subjects, in response to unattended tone pips. Magnetic field data was used to estimate location, orientation, depth, and strength of the 100-ms latency evoked field component (M100). M100 source locations did not significantly differ in left and right hemispheres. Previous studies in six normal males demonstrated M100 sources to be significantly further anterior in the right hemisphere. Compared to the previously reported male subjects, M100 sources in the right hemisphere of these females were significantly further posteriorly, by a mean value of 2.1 cm. These findings, while preliminary, support sex-related functional and/or structural differences in the superior temporal lobe, and would be compatible with the female right temporal planum extending further posteriorly. They suggest MEG recordings may be a useful addition to studies of sex-related difference in brain function and/or structure.

Adult↗
PubMed1991

A microcomputerized task assessment of cognitive change in normal elderly and young adults.

There is need for efficient, acceptable quantitative measures of cognitive differences with senescence which, in addition, have potential to discriminate mild dementia from the performance of normal elderly. A microcomputerized method designed to assess attentional capacity was administered to two elderly age groups, 68-79 and 80-87 years of age. A comparison group of young adults, 25-35 and 35-45 years of age, was similarly studied. The two tasks in the procedure (the tracking task, consisting of following a randomly moving target on a video screen, and the probe task, consisting of visual monitoring of a randomly elongating dot in the video screen) are performed separately and then simultaneously (dual task). The tracking task discriminated between the younger groups. Both the tracking and the probe task discriminated between the two older age groups. On discriminant analysis, the best variables for distinguishing older age groups were the logarithms of the single task scores. The performance scores of both elderly age groups were lower on the dual tasks compared with single tasks, but with significant performance decreases only in the probe scores. Comparing all four age groups, the older groups performed less well on the tasks and particularly poorly on the dual tasks. There were no significant gender effects. These initial data will be useful in application of the method for purposes of discriminating mild dementia from normal senescence, and possibly the effects of drugs used to enhance cognitive function.

Adult↗
PubMed1991

Volume-activated taurine efflux from skate erythrocytes: possible band 3 involvement.

In a previous study (L. Goldstein, S.R. Brill, and E.V. Freund, J. Exp. Zool. 254: 114-118, 1990) it was suggested that volume-activated (VA) taurine efflux from skate (Raja erinacea) erythrocytes might involve the anion exchanger band 3. The aim of the present study was to obtain further evidence for (or against) this possibility. We found that in addition to stilbene disulfonates, two other band 3 inhibitors, N-(azido-2-nitrophenyl)-2-amino sulfonic acid (NAP)-taurine and niflumic acid, also inhibit VA taurine efflux. In addition, there is a close relationship between the dose-response curves for 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid inhibition of VA taurine efflux and sulfate efflux. Furthermore, taurine influx, as well as efflux, is activated by volume expansion, as would be expected with transport facilitated by band 3. However, sulfate (a known band 3 substrate) efflux is not activated by volume expansion, and sulfate influx is only activated minimally, but sulfate does inhibit VA taurine uptake. Thus there is considerable evidence in favor of the involvement of band 3 in VA taurine efflux, but the issue of the sulfate fluxes remains to be resolved.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1991

Taurine secretion in cultured winter flounder renal epithelium.

The mechanism for the secretion of taurine by the marine fish kidney was examined in flounder renal primary cultures and teased tubules. The question addressed was whether the secretion of taurine, but not beta-alanine, a related beta-amino acid, is due to differences in their basolateral uptake, intracellular concentration, or luminal efflux mechanism. Aminooxyacetate (AOA) (10 mM), an inhibitor of beta-alanine oxidation, allowed the basolateral beta-alanine accumulation (measured in teased tubules) and the beta-alanine intracellular concentration (measured in primary cultures) to be similar to that for taurine. However the addition of AOA did not promote the net secretion of beta-alanine (measured as unidirectional fluxes in the cultured epithelium mounted in an Ussing chamber). The organic anions bromcresol green (BCG) (0.1 mM) and probenecid (1 mM) inhibited the net secretion of taurine by affecting the luminal efflux step. This suggests that a BCG- and probenecid-sensitive carrier in the luminal membrane facilitates the cell-to-lumen efflux of taurine and thus achieves net secretion.

Aminooxyacetic Acid↗