Drug policy: striking the right balance

Drug policy should strike the right balance between reducing the harm done by psychoactive drugs and reducing the harm that results from strict legal prohibitions and their enforcement. It is concluded, from a cost-benefit analysis based on pharmacologic, toxicologic, sociologic, and historical facts, that radical steps to repeal the prohibitions on presently illicit drugs would be likely, on balance, to make matters worse rather than better. Specific recommendations are offered for ameliorating the dangers to users and to society that are posed by each addictive drug.

Regulation of insulin receptor functions by a peptide derived from a major histocompatibility complex class I antigen

A 25 residue peptide, Dk-(61-85), derived from the alpha 1 domain of a murine MHC class I molecule (H-2Dk), enhances cellular glucose uptake, prolongs the effect of insulin, and inhibits insulin receptor internalization without affecting insulin binding or dissociation. Full effect of the peptide is obtained at 10-100 microM. The magnitude of the peptide-mediated enhancement of glucose uptake is insulin dependent and is at maximum approximately 50% above that of full insulin stimulation, excluding a merely insulinomimetic action of the peptide. Dk-(61-85) does not interact directly with the glucose transporter molecule. Furthermore, the peptide-mediated inhibition of insulin receptor internalization results in 2-3 times more receptors in the plasma membrane. The peptide also causes hypoglycemia in rats. The biological activity of Dk-(61-85) suggests that an important nonimmunological role of MHC class I molecules is to affect some of the key functions of ligand-activated receptors.

Chimeric opioid peptides: tools for identifying opioid receptor types

We synthesized several chimeric peptides in which the N-terminal nine residues of dynorphin-32, a peptide selective for the kappa opioid receptor, were replaced by opioid peptides selective for other opioid receptor types. Each chimeric peptide retained the high affinity and type selectivity characteristic of its N-terminal sequence. The common C-terminal two-thirds of the chimeric peptides served as an epitope recognized by the same monoclonal antibody. When bound to receptors on a cell surface or membrane preparation, these peptides could still bind specifically to the monoclonal antibody. These chimeric peptides should be useful for isolating mu, delta, and kappa opioid receptors and for identifying opioid receptors on transfected cells in expression cloning procedures. The general approach using chimeric peptides should be applicable to other peptide receptors.

Dextrorphan binds to opioid receptors in guinea-pig brain membranes and is an antagonist at opioid receptors in myenteric plexus

Dextrorphan (+)-tartrate, purified by repeated crystallization to remove all traces of the enantiomer levorphanol, binds to mu, delta, and kappa sites on guinea-pig brain membranes with lower affinities (by a factor of 400-3200) than levorphanol. In the guinea-pig ileum myenteric plexus longitudinal muscle preparation (GPI), dextrorphan, at 100-200 microM, inhibits the electrically stimulated twitch, but this action is not blocked or reversed by naloxone; both (+)- and (-)-naloxone produce similar non-opioid twitch inhibition at comparable concentrations. At 10-20 microM, dextrorphan blocks and reverses the twitch inhibition due to mu and kappa agonists, but the blockade can be overcome only partially by increasing the agonist concentration. We conclude that dextrorphan is an opioid ligand with low affinity and with antagonist effect on opioid receptors in the GPI.

Interleukin-2-dependent control of disease development in spontaneously diabetic BB rats

Long-term treatment with recombinant interleukin-2 (IL-2) of diabetes-prone BB rats had contrasting effects in two different BB rat sublines. Diabetes development was enhanced in the subline with a low intrinsic diabetes risk and suppressed in the subline with a high diabetes risk. IL-2 treatment started between 35 and 42 days of age and lasted for 3 months. In subline 1, diabetes incidence increased from 23% to 53% (P less than 0.01), in subline 2 it decreased from 73% to 32% (P less than 0.01). The two sublines differed in serum levels of factors controlling IL-2 synthesis and activity. Mean IL-2 inhibitory activity was higher in subline 2 (between 140% and 290% of levels in subline 1, P less than 0.01). Conversely, mean concentrations of thymosin alpha 1 and beta 4 were higher in subline 1 (between 140% and 200% of levels in subline 2, P less than 0.01). Thus the two sublines differ in their response to exogenous IL-2 and also in serum levels of mediators affecting availability of IL-2. We conclude that an internal network of hormonal factors, including IL-2, contributes to the control of diabetes development in the BB rat.

Optimizing the performance of Doppler blood-flow probes in extra-corporeal circuits

A theory is developed to improve the signal-to-noise (S/N) ratio of clamp-on Doppler blood-flow probes by optimizing their operating frequency for the tubing utilized in extra-corporeal blood circuits. The theoretical results can be used to increase the magnitude of both the S/N and Doppler frequency shift and to produce a greater tolerance of S/N to variations in the dimensions and acoustic parameters of Tygon tubes. It is shown that thin tube walls improve the S/N and reduce the effect of temperature variations on the magnitude of the S/N. Measurements were performed on various Tygon tubes and their acoustic attenuations obtained. These values were used to predict an optimum operating frequency of 1.78 MHz for the de facto standard tubing having 3/32-in wall thickness. If a 1/16-in wall thickness were substituted, then the optimum operating frequency would be 2.67 MHz and the S/N would increase by 14.54 dB.

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.

The cost of intensive and special care of the newborn

The cost of providing intensive (level-3) and special (level-2) care for newborn infants in a tertiary perinatal service was determined prospectively and was expressed in 1984 Australian dollars. Direct costs that were expressed per occupied bed-day were $690 for level-3, high-dependency care; $421 for level-3, low-dependency care; $544 for over-all level-3 care; $242 for level-2, high-dependency care; $170 for level-2, low-dependency care; and $201 for over-all level-2 care. Each level of care generated additional costs of $42 per occupied bed-day. Taking these additional costs into account, the over-all occupied bed-day cost of level-3 and level-2 neonatal care was $339. The major components of this over-all cost were: nursing staff members, 50%; medical staff members, 11%; consumable and recyclable items, 12%; and diagnostic services, 8%.

Inhibition of insulin receptor phosphorylation by peptides derived from major histocompatibility complex class I antigens

Peptides from the alpha 1 region (residues 61-85) of the D and K molecules of the major histocompatibility complex class I antigens inhibit insulin-induced tyrosine kinase activity of the purified human insulin receptors (IRs) as measured both by autophosphorylation and IR-mediated substrate [poly(Glu,Tyr)] phosphorylation. Half-maximal effect of the Dk-(61-85) peptide on IR autophosphorylation is obtained at 1.2 microM, and almost complete inhibition of IR kinase activity is obtained at 10 microM peptide. The corresponding K kappa-(61-85) peptide has a significantly weaker effect on autophosphorylation. No such effects are observed with nine peptides of similar length, but unrelated to major histocompatibility complex class I antigens. Neither of the major histocompatibility complex class I-derived peptides has any effect on the constitutively active kinase of a genetically engineered cytoplasmic IR domain. Further, insulin binding to IR is unaltered in the presence of the major histocompatibility complex class I-derived peptides. The inhibitory activity of the peptides on insulin-induced IR phosphorylation facilitated the observation that IRs require insulin to become substrate for an independent tyrosine kinase. In the presence of an inhibitory peptide, the constitutively active cytoplasmic IR kinase domain only phosphorylates the intact IR in the presence of insulin. We conclude that the tyrosine kinase activity of IRs may be altered by peptide interaction at an allosteric site and, moreover, IRs require insulin to assume a conformation permitting phosphorylation by an independent kinase.

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.

Is there a relationship between DNA sequences encoding peptide ligands and their receptors?

It has been suggested that the coding for a ligand and its receptor may have originated in inverse complementary strands of the same DNA. This would imply a deficiency of stop codons in the complementary strand of the ligand message sequence. We have sought evidence of such deficiencies by an analysis of the usage of selected codons in 23 human neuropeptide and hormone mRNA sequences. We have also searched directly for similarities between substance K or substance P and the substance K receptor. Although bovine proopiomelanocortin has an open reading frame for the full extent of the inverse complement of the coding region, this seems to be a unique case. The data as a whole do not support the hypothesis.

"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.

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.

Synthesis of the skeleton of the morphine molecule by mammalian liver

The possibility that morphine could be synthesized in animals has long been considered and a pathway in mammalian brain analogous to that in the opium poppy has been proposed. Substances have been detected in mammalian brain that are recognized by antisera raised against morphine. Recently we reported the presence of three such immunoreactive substances in bovine hypothalamus and adrenal, and in rat brain, and the definitive identification of two of them by gas chromatography-mass spectrometry as morphine and codeine. Incorporation of a labelled precursor has demonstrated the biosynthesis of morphine in the opium poppy from tyrosine-derived units (see Fig. 1). Intramolecular coupling of reticuline to form salutaridine is the critical step that generates the morphine skeleton (morphinan) and the stereochemistry of the morphinan series. We now report the conversion in vivo and in vitro of reticuline to salutaridine by rat liver, but this conversion is not detectable in rat brain and bovine adrenal. This is the first direct demonstration of the synthesis of a morphinan in an animal tissue and also supports the hypothesis that morphine and codeine in brain and adrenal are of endogenous origin.

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.

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.

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.

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.

Morphine and codeine from mammalian brain

Recently, we described the presence of six immunoreactive (ir) morphinans in bovine adrenal and hypothalamus and identified one as morphine [Goldstein, A., Barrett, R. W., James, I. F., Lowney, L. I., Weitz, C. J., Knipmeyer, L. L. & Rapaport, H. (1985) Proc. Natl. Acad. Sci. USA 82, 5203-5207]. We now report that ir morphinans corresponding to the previously reported peak 1 (morphine), peak 4, and peak 5 are consistently present in extracts of bovine hypothalamus and variably present in extracts of bovine adrenal and rat brain. We no longer detect the previously reported peaks 2, 3, or 6, and we have established that they were contamination artifacts. Peak 1 is coeluted with morphine in two distinct reversed-phase HPLC systems, as is peak 4 with codeine. We have purified peak 1 and peak 4 compounds from bovine hypothalamus and determined their identities by gas chromatography/mass spectrometry (GC/MS): peak 1 is confirmed to be morphine and peak 4 is codeine.

An analysis of 161 falls from a height: the 'jumper syndrome'

Vertical deceleration injuries represent a distinct form of urban blunt trauma. We reviewed 161 adult patients, admitted over 36 months, who jumped or fell from a height of one to seven stories and survived emergency department resuscitation. Charts and radiographs were analyzed to identify common injuries, complications, and causes of death. Those who fell five or more stories had a mean ISS of 41, for a predicted survival of 50% but actual survival of 83%. Virtually all these patients had multiple fractures. Sixty per cent of them presented in shock, yet more than two thirds had angiographically demonstrated retroperitoneal hemorrhage as their major source of bleeding. Thirteen patients had significant intra-abdominal injuries, with only one associated with major hemorrhage. Utilizing early diagnostic peritoneal lavage, ten of 13 patients explored had a therapeutic laparotomy. Hollow viscus perforations accounted for about one half of the abdominal injuries, including three duodenal injuries. Conclusions. 1) Patients who present in shock after falls from height are much more likely to be bleeding from retroperitoneal than intraperitoneal sources. 2) Early tap and lavage followed by emergency angiography and transcatheter embolization is the treatment of choice in this group of patients. 3) Although these patients often have multiple complex injuries, the prognosis for long-term survival is good. Therefore, we advocate early aggressive operation stabilization of fractures to permit patient mobilization, facilitate pulmonary toilet and nursing care, and to decrease long-term disability.