Midwakh/dokha tobacco use in the Middle East: much to learn.

Many alternative tobacco products (ATPs), such as hookahs, have grown in popularity and use beyond their locale of origin and are therefore becoming a significant global public health concern. This article provides an overview of an under-reported and understudied ATP, dokha, which is smoked in a midwakh pipe. It describes the state of tobacco control in the Arabian Gulf region where midwakh smoking appears to be most common, the history of midwakh and dokha use, and what is known about midwakh smoking from the published literature. On the basis of the stark lack of data on midwakh use, we suggest priority areas to focus future research. Preliminary data and observations from health providers and the public health sector suggest that midwakh smoking may pose challenges to the tobacco control efforts in the Arabian Gulf region. If it is emerging as a new ATP outside this region, there could be a significant impact on tobacco control strategies globally.

X-ray structure of the major adduct of the anticancer drug cisplatin with DNA: cis-[Pt(NH3)2(d(pGpG))].

Crystals of the adduct of the anticancer drug cis-diamminedichloroplatinum(II), cis-DDP, with d(pGpG), its putative target on DNA in the cancer cell, have been obtained and used in an x-ray crystallographic study to elucidate the molecular structure to atomic resolution. Each of the four crystallographically independent cis-[Pt(NH3)2(d(pGpG))] molecules is comprised of a square-planar platinum atom bonded to two ammonia ligands and two N(7) atoms of guanosine nucleosides from the same chain. Base stacking of the two adjacent guanine rings is completely disrupted by coordination to the cis-(Pt(NH3)2)2+ unit. Comparison of the backbone and deoxyribose ring torsion angles with those found by previous (nuclear magnetic resonance spectroscopy) studies of this adduct in solution demonstrates that the solid state geometry is substantially the same as that in solution. The relevance of these results to the molecular mechanism of action of cis-DDP is discussed.

The interaction of the Chrna5 D398N variant with developmental nicotine exposure.

A single nucleotide polymorphism (SNP) in CHRNA5 (rs16969968, change from an aspartic acid [D] to asparagine [N] at position 398 of the human α5 nicotinic acetylcholine receptor subunit) has been associated with increased risk for nicotine dependence. Consequently, carriers of the risk variant may be at elevated risk for in utero nicotine exposure. To assess whether this gene-environment interaction might impact nicotine intake in developmental nicotine-exposed offspring, we utilized a mouse expressing this human SNP. D and N dams drank nicotine (100 µg/mL) in 0.2% saccharin water or 0.2% saccharin water alone (vehicle) as their sole source of fluid from 30 days prior to breeding until weaning of offspring. The nicotine (D Nic, N Nic) or vehicle (D Veh, N Veh) exposed offspring underwent a 2-bottle choice test between postnatal ages of 30 to 46 days. N Nic offspring consumed the most nicotine at the highest concentration (400 µg/mL) compared with all other groups. In contrast, D Nic offspring drank the least amount of nicotine at all concentrations tested. Nicotine-stimulated dopamine (DA) release measured from striatal synaptosomes was increased in D Nic offspring, while decreased in N Nic offspring relative to their genotype-matched controls. These data suggest that the α5 variant influences the effect of developmental nicotine exposure on nicotine intake of exposed offspring. This gene-environment interaction on striatal DA release may provide motivation for increased nicotine seeking in N Nic offspring and reduced consumption in D Nic offspring.

Altered leukocyte protein kinase activity in atopic dermatitis.

Previous studies have demonstrated elevated cyclic-AMP-specific phosphodiesterase (PDE) activity in mononuclear leukocytes (MNL) from patients with atopic dermatitis (AD). We questioned whether increased kinase activation could account for this observation. In these studies, we measured abnormally lower basal calcium/phospholipid-dependent protein kinase (PK-C) phosphorylation in MNL from patients with AD. Basal cAMP-dependent protein kinase (PK-A) phosphorylation was concomitantly higher in MNL from patients with AD. These results are in agreement with earlier reports that PK-A activity may have a negative influence on PK-C activity in certain cell systems. Stimulation with the H1-histamine agonist, thiazolylethylamine (TEA), of MNL from normal donors but not patients with AD, resulted in statistically significant increases in PK-C phosphorylation. This implies receptor down regulation or functional desensitization in AD cells. Altered basal protein kinase phosphorylation and abnormal response to selective histamine agonists seen in MNL from patients with AD could explain elevated PDE activity.

Strychnine-sensitive modulation is selective for non-noxious somatosensory input in the spinal cord of the rat.

Touch-evoked allodynia, an important symptom of clinical neural injury pain, can be modelled acutely and reversibly in the urethane-anesthetized rat using intrathecal (i.t.) strychnine (STR). Allodynia, after i.t. STR (40 micrograms), is manifest as a significant enhancement of cardiovascular and motor responses evoked by normally innocuous brushing of the hair (hair deflection), as compared to responses evoked by either hair deflection after i.t. saline (SAL), or to i.t. STR (40 micrograms) with no tactile stimulus. The present study investigated: (1) the pharmacology of afferent neural inputs involved in STR-dependent allodynia using neonatal capsaicin and the non-NMDA receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline (NBQX); and (2) the effect of i.t. STR on responses evoked by peripheral noxious stimulation. Neonatal capsaicin (25 mg/kg, s.c., post-natal day (PND) 1, and 50 mg/kg, s.c., PND 2, 3, 4, 11, 25, 55 and 85) significantly attenuated the responses evoked by noxious mechanical, thermal or chemical stimuli, but had no effect on STR-dependent allodynia. All hair deflection-evoked, STR-dependent responses were dose-dependently inhibited by i.t. NBQX. The ED50 values and 95% confidence intervals were 10.4 micrograms (5.5-19.6) for the motor withdrawal response, 14.4 micrograms (8.6-24.0) for changes in MAP and 12.2 micrograms (6.8-21.8) for changes in HR. Cortical EEG synchrony was unchanged by i.t. NBQX confirming its spinal locus of action. Intrathecal STR neither reduced nor enhanced the responses elicited by noxious stimuli in capsaicin- or vehicle-pretreated rats. These results indicate that STR-dependent allodynia is initiated by primary afferents not normally involved in nociception (possibly A beta-fibers), and that STR-sensitive modulation in the spinal cord is selective for non-noxious sensory input. The sensitivity of STR-dependent allodynia to non-NMDA receptor antagonists, and the failure of i.t. STR to produce hyperalgesia to mechanical, thermal or chemical noxious stimuli, confirm the independence of nociceptive pathways and STR-sensitive afferent inputs in this model.

Intrathecal oxymetazoline does not produce neurotoxicity in the spinal cord of the rat.

To determine if intrathecal (i.t.) oxymetazoline (OXY) induces histological evidence of spinal neurotoxicity, male, Sprague-Dawley rats (300-450 g; implanted with an i.t. catheter) were treated with i.t. saline or 100 nmol OXY twice daily for 3 days, or 200 or 300 nmol OXY once daily for 3 days. Spantide (D-Arg1, D-Try7,9, Leu11-substance P; 0.067 nmol = 0.1 microgram, 0.167 nmol = 0.25 microgram or 0.334 nmol = 0.5 microgram) or capsaicin (0.164 mumol = 50 micrograms), given as a single i.t. injection, were used as positive controls. Animals were killed 12 h after the last injection of saline or OXY, and 72 h after spantide or capsaicin. Spinal cord sections (L1 and adjacent segments) were examined by light microscopy for changes in gross morphology, substance P-like immunoreactivity (SP-IR) and calcitonin gene related peptide-like immunoreactivity (CGRP-IR). All doses of i.t. OXY produced antinociception (tail-flick ED50 = 53.7 nmol, paw pressure withdrawal ED50 = 93.3 nmol). Rectal temperature decreased by 1.5-2.4 degrees C up to 12 h after 100 nmol of i.t. OXY. There were no signs of inflammation or necrosis, and no detectable loss or damage to either spinal afferents or motor neurons as judged by SP-IR and CGRP-IR structures in spinal cords of OXY-treated animals (all doses) as compared to i.t. saline controls. Spantide (0.1 microgram) had no antinociceptive or neurotoxic effect; 0.25 microgram induced irreversible loss of the TF reflex and transient hind limb paralysis; 0.5 microgram induced irreversible loss of TF and PP responses, permanent hind limb paralysis, bladder and bowel dysfunction. The spinal cords from these animals showed signs of extensive necrosis, cavitation, and haemorrhage in the ventral horn accompanied by a loss of CGRP-IR motor neurons. Capsaicin-treated rats exhibited a permanent loss of the TF but not the PP response and a marked reduction of SP-IR spinal afferents in the dorsal horn. It is concluded that i.t. OXY produces antinociception in the rat with no detectable spinal neurotoxicity as assessed by parameters which are sensitive to the neurotoxins, spantide and capsaicin.

Intrathecal oxymetazoline produces analgesia via spinal alpha-adrenoceptors and potentiates spinal morphine.

The intrathecal (i.t.) injection of 100 nmol of oxymetazoline to male, Sprague-Dawley rats significantly increased tail flick latency and paw pressure threshold for 10 h as compared to i.t. saline-treated rats. Oxymetazoline-induced antinociception was accompanied by a 2 degree C decrease in rectal temperature and a delayed but mild sedative effect. Intrathecal phentolamine (50 micrograms), injected 8 h after i.t. oxymetazoline, completely reversed the analgesic and hypothermic effects but did not affect sedation. The intravenous injection of oxymetazoline (100 nmol) had no effect in the paw pressure test and virtually no effect in the tail flick test. Co-injection of i.t. morphine and i.t. oxymetazoline in a molar ratio of 1:28 resulted in significant potentiation of their antinociceptive effects as determined by isobolographic analysis. For i.t. morphine alone, the ED50 and 95% confidence interval (95% CI) was 3.8 nmol (2.8-5.6) in the tail flick test and 7.7 nmol (5.4-12.8) in the paw pressure test. In the combination, the ED50 (95% CI) of i.t. morphine was 0.7 nmol (0.6-0.8) in the tail flick test and 1.2 nmol (1.1-1.4) in the paw pressure test, corresponding to an approximate 6-fold increase in potency. The data indicate that: (1) the antinociceptive and hypothermic effects of i.t. oxymetazoline at 8 h are mediated by spinal alpha-adrenoceptors; (2) peripheral sites, and probably supraspinal sites, do not contribute to i.t. oxymetazoline-induced antinociception [corrected]; and (3) oxymetazoline potentiates the analgesic effects of morphine in the spinal cord of the naive rat.

Molecular structure of the complex formed between the anticancer drug cisplatin and d(pGpG): C222(1) crystal form.

The three dimensional molecular structure of the adduct formed between the anticancer drug cisplatin and a DNA dinucleotide d(pGpG) has been determined by x-ray diffraction analysis at 1.37 A resolution and refined to a final R-factor of 0.11. This structure, solved by using data from a previously reported crystal form in the space group C222(1), resembles that found in the space group P2(1)2(1)2 (Sherman, et al., Science, 230, 412-417, 1985; ibid, J. Amer. Chem. Soc. 110, 7368-7381, 1988). In both structures, four crystallographically independent cis-[Pt(NH3)2(d(pGpG]] molecules aggregate into a tetrameric cluster that is stabilized by a large number of intermolecular hydrogen bonds and base-base stacking interactions. In each molecule, the platinum atom is coordinated to the N7 atoms of two guanine bases arranged in a head-to-head orientation, resulting in a large dihedral angle between the guanines. Intermolecular guanine-guanine base pairings between different intrastrand crosslinked molecules are used extensively in the crystal lattice.

Evaluation of DEXON suture in cataract surgery: a study using a finer gauge material.

Gauge 7-0 DEXON polyglycolic acid sutures were used in 25 cataract extractions. The suture material handled well, formed small knots, and gave excellent results in all cases. The fine gauge suture is well suited for use in intraocular surgery.

Evaluation of an improved suture for cataract surgery.

An improved synthetic absorbable suture for ophthalmic surgery, 8-0 Dexon "S" polyglycolic acid, was evaluated in 25 cataract extractions and, in 5 cases, compared with 8-0 Vicryl polyglactin sutures. Dexon "S" sutures caused less tissue drag than Vicryl sutures; Vicryl was more easily knotted. With respect to handling, knotting, tissue drag, absorption, and postoperative complications, the improved Dexon suture was found to be well suited for use in cataract surgery.

Clinical comparison of pilocarpine preparations in heavily pigmented eyes: an evaluation of the influence of polymer vehicles on corneal penetration, drug availability, and duration of hypotensive activity.

Heavily pigmented eyes have been shown to be relatively resistant to pilocarpine, and present special problems in management of open-angle glaucoma. Studies have suggested that the hypotensive effect of pilocarpine may be influenced by the vehicle; therefore, 13 relatively resistant black patients (26 eyes) were selected for a clinical comparison of pilocarpine as delivered in two different polymer vehicles. One vehicle was composed of 1.67% polyvinylpyrrolidone and BP water-soluble polymers (Adsorbobase); the other of hydroxypropyl methylcellulose 0.5%. All patients had been under treatment with the pilocarpine/methylcellulose preparation; 20 of the 26 eyes were judged to be uncontrolled (IOP above 21 mm Hg). Control of intraocular pressure was promptly obtained with the pilocarpine/Adsorbobase solution, and maintained at lower pilocarpine concentrations than with the previous therapy. Often, frequency of instillation could be decreased. This clinical comparison suggests that the Adsorbobase vehicle appreciably enhances corneal penetration and availability of pilocarpine. Three cases are discussed demonstrating the need for titration when instituting a new therapy with as little as one fourth the concentration of the previous pilocarpine therapy.

Further evaluation of DEXON suture for cataract surgery: a study using 9-0 monofilament suture.

Gauge 9-0 DEXON polyglycolic acid suture, monofilament, was used in 20 cataract extractions. The suture handled well and gave excellent results in all cases. The fine gauge, monofilament suture is suited for use in cataract surgery.

Evaluation of Dexon suture in ophthalmic surgery.

6-0 Dexon (polyglycolic acid-PGA) suture was used in 30 eyes of 25 patients in surgical procedures which included cataract extraction, strabismus surgery, and ocular plastic surgery. The suture was found to hold the wound firmly, was not absorbed prematurely, was absorbed completely at a predicted time, was relatively easy to use although the knots were large, did not cause any infection or undue tissue reaction, and did not result in any wound dehiscence or vitreous loss.

Measures of functional status in community-dwelling elders.

OBJECTIVE: To evaluate two performance-based measures of functional status and assess their correlation with self-report measures. DESIGN: Cross-sectional study. PARTICIPANTS: Of the 363 community-dwelling elders enrolled in a trial of comprehensive geriatric assessment who participated, all had at least one of four target conditions (urinary incontinence, depression, impaired functional status, or history of falling). MEASUREMENTS: Two performance-based measures, National Institute on Aging (NIA) Battery, and Physical Performance Test (PPT), and three self-report functional status measures, basic and intermediate activities of daily living and the Short-Form-36 (SF-36) physical functioning subscale, were used. Measures of restricted activity days, patient satisfaction and perceived efficacy were also used. MAIN RESULTS: All measures were internally consistent. There was a high correlation between the NIA and PPT (kappa = 0.71), while correlations between the performance-based and self-report measures ranged from 0.37 to 0.50. When patients with values above the median on the two performance-based measures were compared with those below, there were significant differences (p

Long-term diabetes alters the hepatobiliary clearance of acetaminophen, bilirubin and digoxin.

The effect of insulin-dependent diabetes on hepatobiliary clearance of acetaminophen, bilirubin and digoxin was determined using Sprague-Dawley rats that were treated with a 45 mg/kg dose of streptozotocin 28 days before experimentation. Urinary excretion of acetaminophen was increased 280%, whereas biliary excretion was decreased 65% and total clearance was unchanged. Both steady-state volume of distribution and elimination half-life of acetaminophen were decreased in diabetic rats by 23 and 25%, respectively. Biliary excretion of glucuronide and sulfate conjugates was decreased by 75 and 50%, respectively, whereas parent acetaminophen excretion was unchanged. The glutathione conjugate was only detected in normal and insulin-treated rats; however, comparable levels of a cysteine conjugate were detected in bile of diabetic rats. Administration of insulin reversed the hyperglycemia and the changes in volume of distribution, elimination half-life and glutathione excretion. Other diabetes-induced alterations were unchanged. In contrast, digoxin plasma disappearance, volume of distribution and total clearance were significantly increased in diabetic rats, whereas the elimination half-life was decreased. Administration of insulin reversed the changes in serum disappearance and partially reversed the increased biliary excretion of digoxin. No differences were observed for the serum disappearance, glucuronidation or biliary excretion of bilirubin in diabetic vs. normal rats. These data indicate that insulin deficiency for 1 month can alter hepatic excretory function and the pharmacokinetics of commonly used drugs.

Strychnine-dependent allodynia in the urethane-anesthetized rat is segmentally distributed and prevented by intrathecal glycine and betaine.

The blockade of spinal glycine receptors with intrathecal strychnine produces a reversible allodynia-like state in the rat. Thus, hair deflection, in the presence of intrathecal strychnine, induces cardiovascular and motor withdrawal responses comparable with those evoked by noxious thermal, mechanical, or chemical stimulation in the absence of strychnine. In the present study, we mapped the cutaneous sites of abnormal sensitivity to hair deflection throughout the strychnine time course to investigate the segmental distribution of strychnine-induced allodynia. The ability of intrathecal glycine and the glycine derivative betaine to reverse strychnine-induced allodynia was also determined using dose-response analysis. Following intrathecal strychnine (40 micrograms), stroking the legs, flanks, lower back, and tail with a cotton-tipped applicator evoked a pronounced increase in mean arterial pressure, tachycardia, and an abrupt motor withdrawal response in urethane-anesthetized rats. These abnormal responses were only evoked by hair deflection at discrete sites, corresponding to the cutaneous dermatomes innervated by spinal segments near the site of strychnine injection. In rats with intrathecal catheters lying laterally in the subarachnoid space, allodynic sites were observed unilaterally on the ipsilateral side of intrathecal strychnine injection. Recovery from strychnine was complete by 30 min in all affected dermatomes. The cardiovascular and motor withdrawal responses to hair deflection were dose dependently inhibited by intrathecal glycine and intrathecal betaine. The ED50 (95% confidence interval) for intrathecal glycine was 609 (429-865) micrograms for the heart rate response, 694 (548-878) micrograms for the pressor response, and 549 (458-658) micrograms for the motor withdrawal response. The corresponding values for intrathecal betaine were 981 (509-1889), 1045 (740-1476), and 1083 (843-1391) micrograms, respectively. There was no difference in the effect of betaine on sensory-evoked cardiovascular and motor responses. Cortical electroencephalographic activity was not affected by intrathecal glycine or betaine, consistent with a spinal locus of action in reversing strychnine-induced allodynia. These results support the hypothesis that removal of spinal glycinergic modulation from low threshold afferent input with intrathecal strychnine results in segmentally localized, tactile-evoked allodynia.