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Biomedical subjects

A Goldstein

Publications and source records attributed to A Goldstein.

At least 109 records · Page 6Linked to original sources
PubMed1989

Urban-rural and educational differentials in marital status in China.

Since 1950, laws aimed at delaying marriage have been 1 of the major means of slowing population growth in China, where marriage is nearly universal. Age at marriage has risen in recent decades, but not to the same extent in all localities. This article uses cross-tabulated data from China's 1982 census to assess the effects of urban-rural residence and educational level on the ages at which men and women have been marrying. The data also reveal the effects of residence and education on widowhood, divorce, and current marital status. As expected, exposure to development, indicated by urban residence and higher education, is associated with later marriage, but it also increases the likelihood of ever marrying, especially for men. Women's tendency to seek social mobility by marrying men from economically more developed areas results in bachelorhood for a substantial percentage of rural men, especially those who are illiterate.

Asia↗
PubMed1989

Multiple opioid receptors: ligand selectivity profiles and binding site signatures.

Methods are described for studying mu, delta, and kappa opioid binding sites, each without interference from the others. A large array of ligands has been characterized by ligand selectivity profiles, graphic depictions of affinities and selectivities. Binding site signatures have been derived, which uniquely describe each of the three types of sites. The mu, delta, and kappa binding sites have interesting common features and distinctive differences.

Animals↗
PubMed1988

6-Acetylmorphine: a natural product present in mammalian brain.

Recently, we described three substances in bovine hypothalamus, adrenal, and rat brain recognized by antisera raised against morphine, and we identified one as morphine and another as codeine by GC/MS. We now report the identification of the third immunoreactive (ir) morphinan from bovine brain as 6-acetylmorphine by chemical conversion to morphine, GC/MS, and high-resolution mass measurement. 6-Acetylmorphine has not previously been described as a natural product in plants or animals, but it has long been known as the metabolite in part responsible for the biological properties of heroin. However, we have excluded slaughter-house or laboratory contamination by any morphinan as well as derivation from the morphine in tissues during our procedures. 6-Acetylmorphine is known to be more potent than morphine in vivo chiefly by virtue of its greater penetration into the central nervous system. Should morphinans prove to have physiological functions in animals, the properties of 6-acetylmorphine make it ideal for fulfilling the role of a peripheral-to-central hormone.

Animals↗
PubMed1988

"DAKLI": a multipurpose ligand with high affinity and selectivity for dynorphin (kappa opioid) binding sites.

We describe a synthetic ligand, "DAKLI" (Dynorphin A-analogue Kappa LIgand), related to the opioid peptide dynorphin A. A single reactive amino group at the extended carboxyl terminus permits various reporter groups to be attached, such as 125I-labeled Bolton-Hunter reagent, fluorescein isothiocyanate, or biotin. These derivatives have high affinity and selectivity for the dynorphin (kappa opioid) receptor. An incidental finding is that untreated guinea pig brain membranes have saturable avidin binding sites.

Animals↗
PubMed1988

Slice thickness measurements.

A new slice thickness test object is discussed, with results of feasibility tests using 13 transducers from six different commercial scanners presented. Both inplane beamwidth and slice thickness measurements could be easily performed and interpreted. For proper equipment gain settings the slice thickness measurement results were found to be independent of receiver gain with a tissue-mimicking (TM) fill in the test object. This is explained by a simple model in which test object low-amplitude internal fill echoes effectively act as an invariant measurement reference level with respect to the slice thickness profile echoes. This model also predicts that in clinical images the inplane lateral resolution (and slice thickness) will be governed by the local image contrast between adjacent tissues as well as the beam profile. Slice thickness measurement results from various types of real-time transducers demonstrate their inherent slice thickness focal characteristics.

Ultrasonography↗
PubMed1988

Effect of thymosin (fraction 5) on the plasma levels of glucose and glucoregulatory hormones in humans.

Several interactions between thymosin (fraction 5) and the endocrine system have been described in animals, but its effects in humans have not been studied. Plasma levels of glucose, insulin and glucagon were obtained in response to a glucose load before and after treatment with thymosin in eight patients. The glucose tolerance was normal in all subjects and remained so following thymosin administration. No significant changes in the levels of glucagon and insulin were obtained. In six patients, baseline levels of plasma cortisol and ACTH were also obtained. Four out of six patients demonstrated an increase in ACTH levels although the mean differences did not achieve statistical significance. Plasma cortisol levels also did not change significantly. We conclude that thymosin given over a short term is unlikely to significantly influence carbohydrate metabolism. Since four out of six patients showed an increase in basal ACTH levels, it suggests that thymosin may affect the hypothalamic pituitary/adrenal axis. However, further study is needed for complete evaluation of these effects.

Adrenocorticotropic Hormone↗
PubMed1987

Characterization of big dynorphins from rat brain and spinal cord.

To examine the processing of products of the dynorphin gene in the central nervous system, immunoreactive (ir) dynorphin (Dyn) A, Dyn B, Dyn A-(1-8), alpha- and beta-neo-endorphin (alpha- and beta-Neo) in rat brain and spinal cord were measured, using specific antisera after gel filtration and high-performance liquid chromatography (HPLC). Three peaks of Mr about 8, 4, and 2 kDa for ir-Dyn A and ir-Dyn B, and one peak of Mr less than 2 kDa for ir-Dyn A-(1-8), ir-alpha-, and ir-beta-Neo were found both in the brain and in the spinal cord. The 8 kDa peak was recognized by Dyn A and Dyn B antisera and, after hydrolysis by proline-specific endopeptidase, by beta-Neo antiserum. The 8 kDa peak was recognized by a monoclonal antibody against the amino terminal sequence Tyr-Gly-Gly-Phe of all opioid peptides and by an antiserum directed toward the carboxyl terminus of Dyn B, indicating that it contains, from the amino terminal tyrosine of neo-endorphin to the carboxyl-terminal threonine of Dyn B, all 3 opioid peptide regions in the prodynorphin. By means of proline-specific endopeptidase hydrolysis, we also found a big dynorphin precursor (Mr approximately equal to 26 kDa) in both brain and spinal cord.

Animals↗
PubMed1987

Structural requirements for delta opioid receptor binding.

Structural features influencing opioid activity of enkephalin analogs were investigated through the synthesis and evaluation of opioid receptor binding affinities of a series of cyclic dithioether-containing analogs and structurally related linear analogs of the cyclic, disulfide-containing peptides, [D-Pen2, D-Pen5]enkephalin and [D-Pen2, L-Pen5]enkephalin, where Pen (penicillamine) is beta, beta-dimethylcysteine. The major effect of increasing the ring size of the cyclic moiety from disulfide to dithioether analogs was a large decrease in delta opioid receptor binding affinity which suggests that relatively compact conformations of the peptide ligand are necessary for optimal binding to this receptor. The effect of bulky, hydrophobic residues at position 2 in the peptide chain was evaluated by preparing the linear analogs, [D-t-Leu2, D-t-Leu5]enkephalin (t-Leu, 2-amino-3,3-dimethylbutanoic acid) and [D-Abu2, D-t-Leu5]enkephalin (Abu, 2-aminobutanoic acid). The former analog was found to be 36- and 450-fold less potent at delta and mu receptor sites, respectively, than was the latter, suggesting that bulky side chain substituents in position 2 of enkephalin analogs lead to a deleterious steric interaction at delta and particularly at mu receptors.

Animals↗
PubMed1987

Ligand dissociation constants from competition binding assays: errors associated with ligand depletion.

The dissociation constant of a ligand at a binding site (e.g., receptor, antibody) is often determined indirectly by competitive displacement of a radioligand. It is well known that such a determination may be seriously in error unless the free concentrations of both the radioligand and the unlabeled ligand can be measured. By means of computer simulations we have explored the conditions under which this error may occur and its magnitude. We offer guidelines for recognizing a probably inaccurate dissociation constant, and we show how, in some cases, a correction can be made. The problem addressed here is not only a theoretical one; it can arise in the ordinary performance of competition binding assays.

Binding, Competitive↗
PubMed1987

Vertebral artery injury--diagnosis and management.

The literature on vascular trauma contains little information on the management of vertebral artery injuries. We have reviewed our experience consisting of 23 patients with vertebral artery injuries caused by 19 gunshot wounds, two stab wounds, one shotgun wound, and one blunt injury. Twelve patients sustained unilateral vertebral artery thrombosis, seven patients had vertebral AV fistulae (three jugular vein, four vertebral vein) and four patients sustained mural injury without thrombosis. Six patients (26.1%) developed major neurologic deficits of which five could be directly attributed to CNS missile injury. One patient had transient vertebrobasilar ischemia on the basis of a vertebral AV fistula. Four of the seven vertebral AV fistulae were managed solely by therapeutic embolization and two patients early in the series underwent surgical management alone. One patient had therapeutic embolization of the proximal vertebral artery and operative distal vertebral artery ligation for an AV fistula. The four patients who died (17.4%) did so as a direct result of their CNS missile injury. We conclude that: 1) unilateral vertebral artery occlusion seldom results in a neurologic deficit if there is a normal contralateral vertebral artery and PICA (posterior inferior cerebellar artery) blood supply is preserved; 2) accurate assessment of a vertebral artery injury requires contralateral vertebral arteriogram; 3) management of vertebral artery injury is simplified by proximal, and if possible distal, therapeutic embolization; 4) an anterior approach to the C1-2 vertebral artery is a satisfactory method of obtaining distal surgical control, obviating the need to unroof the bony canal of the vertebral artery; 5) angiography is necessary in penetrating neck trauma to identify occult vascular injuries.

Adolescent↗
PubMed1986

Comparative immuno-removal: a novel method for estimating the concentration of an unknown immunoreactive compound.

We describe a method for estimating the molar concentration of an unknown immunoreactive compound. The amount of antibody required to bind half of a standard is compared to the amount required to bind half of an equal number of immunoreactive equivalents of the unknown. We demonstrate the utility of the method using a morphine antibody affinity resin and compounds structurally related to morphine.

Animals↗
PubMed1986

Brain chemistry and the addictions.

This is a very exciting period for basic discoveries in the field of neuroscience. We can begin to hope for the kinds of understanding that will give us medical insight into the causes and mechanisms of the addictions. Such knowledge may open the way for methods of prevention and treatment by means we can hardly imagine today. Tests for genetic vulnerability to addiction, so that prevention measures can be focused on those who would benefit most? Stimulation of the production of endogenous brain chemicals? Repair of genetic defects in peptide or receptor production? Immunizations? Long-term replacement therapies? Who knows? The next decade or two should see exciting developments leading to practical clinical applications in the field of addiction.

Brain Chemistry↗