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Biomedical subjects

A Zuckerman

Publications and source records attributed to A Zuckerman.

At least 19 recordsLinked to original sources
PubMed1999

Pharmacological characterization of morphine-6-sulfate and codeine-6-sulfate.

Morphine-6-sulfate (M6S) and codeine-6-sulfate (C6S) are mu-selective opiates which have been isolated from brain. M6S is an effective analgesic, with a 30-fold greater potency than morphine in the mouse radiant heat tailflick assay and similar to the active morphine metabolite morphine-6beta-glucuronide (M6G). M6S analgesia is reversed by 3-methoxynaltrexone at low antagonist doses which are inactive against morphine, suggesting that M6S may be acting through the same mechanisms as M6G. Consistent with this possibility, antisense mapping of the MOR-1 clone revealed that M6S analgesia was lowered by probes targeting exon 2 and not by targeting exon 1, a sensitivity profile similar to that of M6G and not morphine. C6S also has analgesic activity at doses approximately 10-fold greater than M6S. However, its characterization was impeded by the appearance of seizures at doses below full analgesic activity. Thus, M6S is a potent analgesic with pharmacological properties similar to M6G. C6S has limited utility due to its high level of toxicity.

Analgesics, Opioid↗
PubMed1999

Antisense mapping KOR-1: evidence for multiple kappa analgesic mechanisms.

In binding assays, both dynorphin B and alpha-neoendorphin are relatively selective for the kappa1b site, unlike U50,488H which has high affinity for both kappa1a and kappa1b sites. In vivo, U50,488H, dynorphin B and alpha-neoendorphin analgesia are reversed by the kappa1-selective antagonist, nor-binaltorphimine (norBNI). Antisense mapping the three exons of KOR-1 revealed that probes targeting all three exons blocked U50,488H analgesia, as expected. However, the selectivity profile of dynorphin B and alpha-neoendorphin analgesia towards the various antisense oligodeoxynucleotides differed markedly from U50,488H, implying a different receptor mechanism of action.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1999

Identification and characterization of three new alternatively spliced mu-opioid receptor isoforms.

We have identified four new mu-opiod receptor (MOR)-1 exons, indicating that the gene now contains at least nine exons spanning more than 200 kilobases. Replacement of exon 4 by combinations of the new exons yields three new receptors. When expressed in Chinese hamster ovary cells, all three variants displayed high affinity for mu-opioid ligands, but kappa and delta drugs were inactive. However, there were subtle, but significant, differences in the binding profiles of the three variants among themselves and from MOR-1. Immunohistochemically, the major variant, MOR-1C, displayed a regional distribution quite distinct from that of MOR-1. Region-specific processing also was seen at the mRNA level. Antisense mapping revealed that the four new exons were all involved in morphine analgesia. Together with two other variants generated from alternative splicing of exon 4, there are now six distinct MOR-1 receptors.

Alternative Splicing↗
PubMed1999

Role of aldosterone in renal vascular injury in stroke-prone hypertensive rats.

Stroke-prone spontaneously hypertensive rats (SHRSP) on 1% NaCl drinking solution and Stroke-Prone Rodent Diet develop severe hypertension and glomerular and vascular lesions characteristic of thrombotic microangiopathy seen in malignant nephrosclerosis. We recently reported that spironolactone, a mineralocorticoid receptor antagonist, markedly reduced proteinuria and malignant nephrosclerotic lesions in these animals. This observation, together with our previous findings that angiotensin-converting enzyme inhibitors prevent the development of vascular damage, suggests that mineralocorticoids, as part of the renin-angiotensin-aldosterone system, play a pathophysiological role in this model. In the present study, we examined whether chronic (2-week) infusion of aldosterone can reverse the renal vascular protective effects of captopril in SHRSP. SHRSP received vehicle (n=8); captopril alone (50 mg. kg-1. d-1, orally) (n=10); aldosterone infusion alone (40 microg. kg-1. d-1, SC) (n=7); or captopril and aldosterone at 20 (n=6) or 40 (n=7) microg. kg-1. d-1. Systolic blood pressure was markedly elevated in all groups. Vehicle- and aldosterone-infused SHRSP developed severe proteinuria and comparable degrees of renal injury (21+/-3% and 29+/-3%, respectively) manifested as thrombotic and proliferative lesions in the arterioles and glomeruli. Captopril treatment reduced plasma aldosterone levels concomitant with marked reductions in proteinuria and the absence of histologic lesions of malignant nephrosclerosis. Aldosterone substitution at 20 or 40 microg. kg-1. d-1 in captopril-treated SHRSP resulted in the development of severe renal lesions (16+/-3% and 21+/-2%, respectively) and proteinuria comparable with that observed in SHRSP given either aldosterone or vehicle alone. These findings support a major role for aldosterone in the development of malignant nephrosclerosis in saline-drinking SHRSP, independent of the effects of blood pressure.

Aldosterone↗
PubMed1998

Identification and differential regional expression of KOR-3/ORL-1 gene splice variants in mouse brain.

KOR-3, also known as ORL-1, is a member of the opioid receptor family, encoding the murine receptor for orphanin FQ/nociceptin. In the current studies we have identified five different splice variants of KOR-3 in mouse brain, three of which have not been previously reported. In addition to variants with a 15 bp deletion at the 3'-end of the first coding exon (KOR-3d) and an 81 bp insertion between the second and third coding exons (KOR-3e), three new variants with insertions of 34 (KOR-3a), 98 (KOR-3b), and 139 bp (KOR-3c) between the first and second coding exons have been obtained. The expression of the three variants in mouse brain varies markedly among brain regions with a distribution which is quite distinct from KOR-3 itself. Of greatest interest was the presence of high levels of KOR-3a in the striatum, a region with no demonstrable KOR-3, and in the cortex. KOR-3c was seen in the periaqueductal gray and hypothalamus, regions where KOR-3 predominated. The brainstem had similar levels of KOR-3, KOR-3a, and KOR-3d. In contrast, KOR-3d was most prominent in the cerebellum. KOR-3b levels were very low throughout.

Alternative Splicing↗
PubMed1998

Cloning and characterization of a mouse sigma1 receptor.

A cDNA clone (S2-1a) isolated from a mouse brain cDNA library, using a guinea pig sigma1 cDNA as probe, has high homology to the predicted protein sequence of the guinea pig (88%) and human (90%) sigma1 receptors. Northern analysis revealed a major mRNA of approximately 1.8 kb in a wide range of mouse tissues, with highest levels in brain, liver, kidney, and thymus. Southern analysis and chromosomal mapping in the mouse suggested a single-copy gene in region A5-B2 of chromosome 4. Expression of the clone in MCF-7 and CHO cells led to a pronounced increase in (+)-[3H]pentazocine binding with a selectivity profile consistent with sigma1 receptors. In vitro translation yielded a protein of approximately 28 kDa, as did transfection of a probe containing the hemagglutinin (HA) epitope (S2-1a.HA) into CHO cells, as determined by western analysis using an antibody directed against HA. (+)-[3H]-Pentazocine binding to immunopurified HA-tagged receptor demonstrated conclusively that S2-1a.HA encodes a high-affinity (+)-[3H]pentazocine binding site with characteristics of a murine sigma1 receptor. An antisense oligodeoxynucleotide designed from S2-1a potentiated opioid analgesia in vivo.

Amino Acid Sequence↗
PubMed1998

Mitogen-activated protein kinase-dependent and protein kinase C-dependent pathways link the m1 muscarinic receptor to beta-amyloid precursor protein secretion.

Full and functionally selective M1 muscarinic agonists (carbachol and AF102B, respectively) activate secretion of the soluble form of amyloid precursor protein (APPs) in PC12 cells expressing the m1 muscarinic receptor (PC12M1 cells). This activation is further augmented by neurotrophins such as nerve growth factor and basic fibroblast growth factor. Muscarinic stimulation activates two transduction pathways that lead to APPs secretion: protein kinase C (PKC)-dependent and mitogen-activated protein kinase (MAPK)-dependent pathways. These pathways operate in parallel and converge with transduction pathways of neurotrophins, resulting in enhancement of APPs secretion when both muscarinic agonist and neurotrophins stimulate PC12M1 cells. These conclusions are supported by the following findings: (a) Only partial blockade of APPs secretion is observed when PKC, p21ras, or MAPK is fully inhibited by their respective specific inhibitors, GF109203X, S-trans, trans-farnesylthiosalicylic acid, and PD98059. (b) K252a, which blocks PKC and phorbol 12-myristate 13-acetate-induced APPs secretion, enhances both muscarinic-stimulated MAPK activation and APPs secretion. (c) Activation of MAPK in PC12M1 cells by muscarinic agonists is Ras-dependent but PKC-independent and is enhanced synergistically by neurotrophins. These results suggest that muscarinic stimulation of APPs secretion is mediated by at least two independent pathways that converge and enhance the signal for APPs secretion at the convergence point.

Amyloid beta-Protein Precursor↗
PubMed1998

Silver-stained nucleolar organizer regions (AgNORs) as a prognostic value in malignant melanoma.

The nucleolar organizer regions (NORs) are chromosomal loops of DNA and proteins involved in ribosomal synthesis. By silver staining, they can be identified as black dots (AgNORs) in the nuclei. Their size and number reflect cell and nuclear activity. Therefore, AgNOR count may correlate with the proliferative activity of tumors. In malignant melanoma, correlation between AgNOR count and the growth phase was found. However, the value of AgNORs in determining prognosis is disputable. Our purpose was to evaluate the role of AgNORs in predicting the biological behavior of melanoma. Paraffin-embedded sections of 30 cases of primary melanoma, 0.4-5 mm thick (mean, 1.6 mm) were stained with silver. Follow-up of all patients was at least 5 years. For each tumor, at least 50 cells were randomly selected for AgNOR count at a final magnification of 500, and the mean of AgNOR content was calculated. Sample parameters corresponded well to the epidemiology and the natural history of melanoma. AgNOR counts (0.78-4.26; mean, 1.42+/-0.72) correlated with tumor thickness (p = 0.01); thus, most superficial tumors had low AgNOR counts, whereas most deep tumors (> or = 1.5 mm) showed high counts. Patients who had tumors with AgNOR counts lower than the median had longer disease-free interval (DFI) than did patients who had tumors with higher counts (p = 0.02). Furthermore, in a multivariate Cox analysis, AgNOR count was independent of tumor thickness in determining DFI (p = 0.05). Therefore, AgNORs may serve as a parameter to predict more accurately the progression of melanomas (mainly thin ones). Larger studies are needed in order to consolidate these preliminary results and to characterize AgNOR value further as a prognostic factor in melanoma.

Adolescent↗
PubMed1998

Mineralocorticoid blockade reduces vascular injury in stroke-prone hypertensive rats.

Chronic treatment of saline-drinking stroke-prone spontaneously hypertensive rats (SHRSP) with agents that interfere with the formation or actions of angiotensin II (Ang II) prevents the development of stroke and renal vascular damage. Ang II, in addition to its direct vascular effects, stimulates the synthesis and release of aldosterone. To assess the role of aldosterone in the development of pathologic changes in these rats, we implanted time-release pellets containing 200 mg of the mineralocorticoid receptor antagonist, spironolactone, into 14 SHRSP at 7.5 weeks of age. Eight SHRSP littermates received placebo pellets. Over the period of study (3 to 4 weeks), systolic blood pressure (SBP) was not different between the groups. Spironolactone did not enhance water and electrolyte excretion. All placebo-treated SHRSP developed marked proteinuria (150+/-6 mg/d) whereas in spironolactone-treated SHRSP, urinary protein excretion (UPE) averaged 39+/-9 mg/d (P<.0001). In a second study to assess effects on survival, 6 SHRSP received spironolactone (10 mg/kg/d) and 6 received vehicle. All but one of the control rats displayed signs of stroke and died by 16 weeks of age, while the spironolactone-treated SHRSP remained asymptomatic through 19 weeks of age (P<.03). At 16 weeks of age, spironolactone-treated SHRSP were severely hypertensive (247+/-3 mm Hg), yet UPE remained at baseline levels. In contrast, preterminal UPE averaged 136+/-13 mg/d in control rats (P<.0001). In both studies, histopathologic examination revealed a marked protective effect of spironolactone against the development of malignant nephrosclerotic and cerebrovascular lesions. These observations indicate a vascular and end organ protective effect of spironolactone in the absence of lowered blood pressure in saline-drinking SHRSP and are consistent with a major role for mineralocorticoids as hormonal mediators of vascular injury.

Aging↗
PubMed1997

Estrogen, progesterone and testosterone receptors in human fetal cartilaginous tissue: immunohistochemical studies.

Computerized image analysis was used to study the distribution in cartilage of receptors to estrogen, progesterone, and testosterone during human fetal development. We have examined three histologically distinct cell groups (hypertrophic, proliferating, and reserve zones) in long bones, vertebrae, and trachea from 19 fetuses. Comparisons were made across gender and gestational age. Contrasting with controls, we examined the density of receptors, the size of the nuclear area in which the receptors were detected, the number of hormone receptor-bearing cells, and the total receptor quantity per sample. We found that estrogen, progesterone, and testosterone receptors were detected in the nuclei of all cell types, in both female and male embryonic cartilaginous tissue. Gender differences were small and inconsistent. Changes associated with gestational age depicted a pattern of hormone receptor manifestation, shifting from the immature cell types to more differentiated cells. This was evident from the receptor densities and from the cellular area in which receptors were sighted. These dynamics are accompanied by a general increase in receptor content per sample, brought about by the concomitant increase in receptor containing area size and cell number. The increase in receptor levels seems to reflect the maturation and growth of the fetal skeleton.

Cartilage↗
PubMed1997

Early appearance of neutralizing antibodies after vaccination with an inactivated hepatitis A vaccine.

Sera from 30 subjects vaccinated with the Pasteur Merieux Serums & Vaccins (PM) inactivated hepatitis A vaccine, and from 30 subjects vaccinated with the Smithkline Beecham (SB) inactivated hepatitis A vaccine, were tested in two laboratories in order to provide comparative data on neutralizing activities of vaccine-induced antibodies. Sera were also evaluated by a modified radioimmunoassay (mRIA) and results were compared to neutralization assays results. Neutralizing antibody titres provided by the two laboratories correlated well (coefficient or correlation 0.42, P < 0.001). Neutralizing antibodies were detected after vaccination with both vaccines, and the kinetics of neutralizing antibody were the same with both vaccines. The titres gradually increased between the second week after the first dose and the post-booster dose (week 28). A strong booster effect of the booster vaccine dose on neutralizing titres was observed. Significantly higher neutralizing antibody titres with the PM vaccine were observed as early immune response on week 2 titres on both series of results. Vaccine-induced neutralizing antibody titres and vaccine-induced antibody mRIA titres correlated well (coefficient of correlation 0.82 and 0.72, respectively, P < 0.0001 in both cases). These results demonstrate early appearance of neutralizing antibody at high titre with the PM vaccine.

Adolescent↗
PubMed1997

Regional renal nitric oxide release in stroke-prone spontaneously hypertensive rats.

Diminished nitric oxide (NO) production has been implicated in the pathogenesis of salt-sensitive hypertension. We questioned whether such a defect is responsible for the malignant hypertension and nephrosclerosis in stroke-prone spontaneously hypertensive rats (SHRSP) fed a high-salt/stroke-prone diet (S) versus a regular diet (R). NO release from 30-minute incubates of cortex and outer and inner medulla were studied in SHRSP at 10, 12, and 16 weeks of age on the S diet versus R diet. SHRSP-S (n=16) exhibited a marked age-dependent increase in NO release, especially in the cortex. Increases were only modest in SHRSP-R (n=21). At 16 weeks, cortical NO was 93+/-25 versus 6+/-1 pmol/mg tissue in SHRSP-S versus SHRSP-R (P<.001). Immunohistochemical staining increased mostly for neuronal, slightly for endothelial, and negligibly for inducible isoforms of NO synthase and was predominantly in the cortex of SHRSP-S versus SHRSP-R. Despite similar hypertension in SHRSP-S versus SHRSP-R (mean arterial pressure, 174+/-7 versus 177+/-2 mm Hg), malignant nephrosclerosis was seen only in SHRSP-S, affecting 22+/-6% of glomeruli and 23+/-4 vessels per 100 glomeruli by 16 weeks. N omega-nitro-L-arginine (15 mg/kg per day) in SHRSP-S (n=6) abrogated the increase in cortical NO but further augmented the hypertension and accelerated lesion development. Wistar-Kyoto rats at 16 weeks on the R diet (n=8) had NO levels similar to those of SHRSP-R, showed increased cortical NO to only 28+/-10 pmol/mg on the S diet (n=9) (P<.05 versus SHRSP-S), but remained normotensive and lesion-free. We conclude that hypertension and lesion development in SHRSP are not due to deficient renal NO. Accelerated onset of malignant nephrosclerosis by NO synthase inhibition suggests that NO is protective in these animals, mitigating the effects of hypertension and S diet on renal pathology.

Aging↗
PubMed1996

Transjugular intrahepatic portosystemic shunt for the management of severe venoocclusive disease following bone marrow transplantation.

Hepatic venoocclusive disease (VOD) is a common, life-threatening complication of bone marrow transplantation (BMT). Portal hypertension is usually present and accounts for many of the clinical manifestations of this syndrome. We describe the results of transjugular intrahepatic portosystemic shunt (TIPS) for the management of VOD after BMT TIPS was performed in six patients with histologically confirmed VOD who had progressive jaundice and ascites. Portal hypertension was improved by TIPS in all patients (mean portal pressure gradient before TIPS, 20.2 +/- 4.6 vs. 6.7 +/- 1.9 mm Hg post-TIPS, P < .004). Three patients who underwent TIPS late in the course of VOD did not demonstrate any clinical improvement after TIPS and expired within 2 weeks of the procedure. The remaining three patients had less advanced disease and demonstrated decreases in serum bilirubin, improvement in coagulopathy, and decreased ascites after TIPS. Two patients subsequently expired, one with persistent histological changes of VOD. The lone survivor continues to do well with resolution of ascites, jaundice, and coagulopathy as of her last outpatient visit. TIPS was an effective method for portal decompression in patients with VOD after BMT, and was associated with clinical improvement in some patients. However, these effects may be transient and may not improve overall survival.

Adult↗
PubMed1996

Analysis of the antibody response in humans with a new inactivated hepatitis A vaccine.

Sera from subjects vaccinated with the Pasteur Merieux (PM) inactivated hepatitis A vaccine (AVAXIM) have been analysed in order: (1) to assess comparability of the results provided by a modified radio-immunoassay (mRIA) in the different laboratories involved in testings of sera during clinical trials and by enzyme-linked immunoabsorbent assay (ELISA) used during development of other inactivated hepatitis A vaccines; (2) to describe the IgM responses elicited by this vaccine compared with one control vaccine [HAVRIX, 720 ELISA antigens units; Smithkline Beecham (SB), Rixensart, Belgium]; (3) to provide comparative data between the PM vaccine and the SB vaccine on neutralizing activities of vaccine-induced antibodies. Vaccine-induced antibody titres evaluated by a mRIA in different laboratories correlated well and validated the comparability of the results obtained in various vaccine trials conducted by PM. Geometric mean titres (GMTs) expressed as milli-international units (mlU/ml) were higher with ELISA especially after the first dose, but seroconversion rates were similar and a good correlation was found between the two assays. IgM vaccine-induced antibodies were detectable in nearly all vaccinated subjects from week 2 after vaccination, with a peak titre between weeks 2 and 4 after the first dose. Comparison of GMTs by the Student Fisher t-test was statistically significant (P < 0.05) only at week 2 with higher titres in PM vaccinees. Neutralizing antibodies were detected after vaccination with the PM inactivated hepatitis A vaccine. The titres gradually increased between the second week after the first dose and the booster dose (week 24). A strong booster effect of the second dose on neutralizing titres was observed. Seroneutralizing titres induced at week 2 in subjects vaccinated with the PM inactivated hepatitis A vaccine were statistically significantly higher (P < 0.05) from those induced by the SB vaccine.

Adolescent↗
PubMed1995

Dehydroepiandrosterone augments M1-muscarinic receptor-stimulated amyloid precursor protein secretion in desensitized PC12M1 cells.

Epidemiologic studies suggest that the age-related decline in dehydroepiandrosterone (DHEA) levels may be associated with Alzheimer's disease (AD). Cholinergic markers also decline with age, and are associated with AD pathology. Activation of m1AChR-transfected PC12 cells (PC12M1) with cholinergic agonists results in secretion of Alzheimer's beta-amyloid precursor protein (APP) which in turn reduces beta-amyloid production. This study examined whether DHEA affects APP processing in m1AChR-transfected PC12 cells. DHEA treatment did not significantly alter basal or m1AChR-stimulated APP secretion. However, DHEA (0.1 microM) significantly diminished the desensitization of APP secretion in cells exposed to carbachol for 24 h. The effect of DHEA on APP processing is probably not related to up-regulation of m1AChR or increased m1AChR-activated phosphoinositide hydrolysis since these parameters did not change following DHEA treatment. These findings imply a possible involvement of DHEA in APP processing. Thus, the age-associated decline in DHEA levels may contribute to decreased APP secretion and a consecutive increase in beta-amyloid deposition, which in turn may play a role in the development of AD.

Amyloid beta-Peptides↗