Encounters with pseudoaneurysms in orthopaedic practice

Thirteen pseudoaneurysms are presented of which five were caused as a complication of pin/wire placement of external fixators (one conventional and four Ilizarov frames). The most common symptom was the presence of profuse persistent bleeding from either the wound or the pin/wire site. In nine patients the pseudoaneurysm was directly caused by a fracture or subsequent fracture stabilisation. Pre-operative evaluation included radiography, arteriography, Doppler and computed tomography (CT) angiography. Depending on the site and size of the pseudoaneurysm management consisted of either ligation, resection and end-to-end anastamosis/vein grafting, lateral suture, endoaneurysmorrhaphy or selective embolisation.A high index of suspicion needs to be maintained following penetrating injury in the vicinity of a major vessel, particularly in the presence of persisting symptoms. External fixators are widely used to treat complex orthopaedic problems. The procedure is technically demanding, requiring a sound knowledge of cross-sectional limb anatomy. Injudicious use may result in potentially life/limb threatening complication of pseudoaneurysm.

Effects of calcium channel blockers on pentylenetetrazol drug discrimination in rats

The effects of the dihydropyridine L-type calcium channel blockers nitrendipine and nimodipine on the pentylenetetrazol (PTZ) drug discrimination, an operant model of anxiety, were investigated. Male Long-Evans rats were trained to discriminate PTZ (16 mg/kg, i.p.) from saline. Both nitrendipine (5.0-25 mg/kg, i.p.) and nimodipine (5.0-25 mg/kg, i.p.) partially substituted for the PTZ discriminative stimulus. However, pretreatment with nitrendipine (25 mg/kg, i.p.) or nimodipine (25 mg/kg, i.p.) produced no change in the PTZ dose-effect function. Rats were given a nutritionally balanced liquid diet containing 6.5% ethanol for 10 days. Rats selected the PTZ drug lever during withdrawal. Subchronic coadministration of nitrendipine (1.25-5.0 mg/kg, i.p., b.i.d.) with ethanol failed to dose-dependently reduce PTZ-lever responding, but it did reverse withdrawal signs. Acute administration of nitrendipine (5, 10, and 20 mg/kg, i.p.) produced marked suppression of lever responding, but it failed to significantly reduce levels of PTZ-lever responding. Although calcium channel blockers reduce signs of ethanol withdrawal, they also markedly reduce rates of behavior and produce no clear effects on anxiety-like behaviors induced by ethanol withdrawal.

Oxidative stress and role of antioxidant and omega-3 essential fatty acid supplementation in schizophrenia

1. Schizophrenia is a major mental disorder that has a lifetime risk of 1% and affects at young age (average age at the onset 24 +/- 4.6 years) in many cultures around the world. The etiology is unknown, the pathophysiology is complex, and most of the patients need treatment and care for the rest of their lives. 2. Cellular oxidative stress is inferred from higher tissue levels of reactive oxygen species (ROS, e.g., O2*-, OH*, OH-, NO* and ONOO--) than its antioxidant defense that cause peroxidative cell injury, i.e., peroxidation of membrane phospholipids, particularly esterified essential polyunsaturated fatty acids (EPUFAS), proteins and DNA. 3. Oxidative stress can lead to global cellular with predominantly neuronal peroxidation, since neurons are enriched in highly susceptible EPUFAs and proteins, and damages DNA is not repaired effectively. 4. Such neuronal peroxidation may affect its function (i.e., membrane transport, loss of mitochondrial energy production, gene expression and therefore receptor-mediated phospholipid-dependent signal transduction) that may explain the altered information processing in schizophrenia. 5. It is possible that the oxidative neuronal injury can be prevented by dietary supplementation of antioxidants (e.g., vitamins E, C and A; beta-carotene, Q-enzyme, flavons, etc.) and that membrane phospholipids can be corrected by dietary supplementation of EPUFAs. 6. It may be that the oxidative stress is lower in populations consuming a low caloric diet rich in antioxidants and EPUFAs, and minimizing smoking and drinking. 7. Oxidative stress exists in schizophrenia based on altered antioxidant enzyme defense, increased lipid peroxidation and reduced levels of EPUFAs. The life style of schizophrenic patients is also prooxidative stress, i.e., heavy smoking, drinking, high caloric intake with no physical activity and treatment with pro-oxidant drugs. 8. The patients in developed countries show higher levels of lipid peroxidation and lower levels of membrane phospholipids as compared to patients in the developing countries. 9. Initial observations on the improved outcome of schizophrenia in patients supplemented with EPUFAs and antioxidants suggest the possible beneficial effects of dietary supplementation. 10. Since the oxidative stress exists at or before the onset of psychosis the use of antioxidants from the very onset of psychosis may reduce the oxidative injury and dramatically improve the outcome of illness.

Behavioral and physiological detection of classically-conditioned blood pressure reduction

Spontaneously hypertensive (SH) rats were trained to discriminate the effects of saline injection from the interoceptive stimuli associated with the blood-pressure-reducing effect of clonidine (0.02 mg/kg, IP) in a drug discrimination procedure. Anise/ethanol and ethanol odors were then systematically paired with clonidine and saline treatment, respectively, outside the drug discrimination setting. As the number of pairings increased, the anise/ethanol (but not the ethanol) stimulus, when given alone, came to both reduce blood pressure and to mimic clonidine's interoceptive stimulus to virtually the same extent as clonidine itself. Both responses induced by the conditioned stimulus (CS+; anise/ethanol odor) were antagonized by the noradrenergic alpha-2 receptor antagonist yohimbine at a dose that did not by itself influence blood pressure. These data support the hypothesis that activation of endogenous factors can be elicited by a CS, and that these factors may furthermore act agonistically at central alpha-2 receptors to reduce blood pressure in hypertensive animals.

Hypoxia augments conversion of big-endothelin-1 and endothelin ET(B) receptor-mediated actions in rat lungs

We have examined the effect of endothelin-1, sarafotoxin-6C, big-endothelin-1 and other agents on perfused lungs from chronically hypoxic rats. Increases in pulmonary perfusion pressure induced by big-endothelin-1, endothelin-1, phenylephrine and potassium chloride were enhanced in hypoxic lungs, while the constrictor action of sarafotoxin-6C was not increased. When basal pulmonary perfusion pressure was raised, low doses of endothelin-1 and sarafotoxin-6C produced decreases in pulmonary perfusion pressure which were significantly greater in chronically hypoxic lungs, whereas responses to sodium nitroprusside were unchanged. Endothelin ET(B) receptor-mediated bronchoconstrictor responses were also potentiated in hypoxic lungs, whereas responses to carbachol were not. In hypoxic lungs, conversion of big-endothelin-1 to endothelin-1 was significantly increased. These data provide evidence for a generalised increase in vasomotor activity in chronically hypoxic lungs, and a more selective increase in endothelin ET(B) receptor-mediated vasodilator and bronchoconstrictor responses. Hypoxia also augments the conversion of big-endothelin-1 to endothelin-1.

Endemic carbapenem-resistant Acinetobacter species in Brooklyn, New York: citywide prevalence, interinstitutional spread, and relation to antibiotic usage

Acinetobacter species are problematic nosocomial pathogens. In November 1997, pathogens isolated by microbiology laboratories were collected from 15 hospitals in Brooklyn, New York. Acinetobacter species accounted for 10% of gram-negative isolates. Only half of Acinetobacter species were susceptible to carbapenems; 11 hospitals had at least 1 isolate resistant to carbapenems. Other Acinetobacter susceptibility rates were as follows: polymyxin, 99%; amikacin, 87%; ampicillin/sulbactam, 47%; ceftazidime, 25%; and ciprofloxacin 23%. Overall, 10% were resistant to all commonly used antibiotics. Genetic analysis by use of pulsed-field gel electrophoresis of 12 carbapenem-resistant isolates revealed 4 strains that were recovered from >1 hospital, which suggests interinstitutional spread. Antibiotic usage data from 11 hospitals revealed that the use of third-generation cephalosporins was associated significantly with the percentage of carbapenem-resistant strains (P=.03). Resistant Acinetobacter species have become endemic in Brooklyn, New York. Citywide strategies that involve surveillance, infection-control practices, and the reduction of antibiotic usage may be necessary to control the spread of these pathogens.

Abecarnil and alprazolam reverse anxiety-like behaviors induced by ethanol withdrawal

This study investigated the effects of a benzodiazepine partial agonist, abecarnil, and a full agonist, alprazolam, on ethanol withdrawal-induced anxiety-like behaviors in rats. Anxiety was assessed in two models: elevated plus maze and pentylenetetrazol (GABA(A) antagonist) discrimination assay. Male rats received an ethanol-containing (4.5%) liquid diet for 7 to 10 days and were tested for withdrawal symptoms 12 h after termination of the diet. In the elevated plus maze, ethanol-withdrawn rats displayed less open arm activity and total arm entries than pair-fed rats. Abecarnil (0.08-0.32 mg/kg, IP) and alprazolam (0.08-1.25 mg/kg, IP) each produced a dose-dependent, full reversal of ethanol withdrawal-induced reduction of open arm activity, but only alprazolam increased the total arm entries. In the pentylenetetrazol assay, ethanol-withdrawn rats selected the pentylenetetrazol lever (100%) over the salin-lever. Abecarnil (0.04-0.32 mg/kg, IP) and alprazolam (0.08-0.32 mg/kg, IP) dose dependently reduced pentylenetetrazol-lever responding to control levels (10-20%). Alprazolam was more potent than abecarnil in reversing ethanol withdrawal-induced decrease in open arm activities, but showed comparable potency and efficacy to abecarnil in blocking the pentylenetetrazol-like ethanol withdrawal stimulus. These results suggest that abecarnil and alprazolam may have therapeutic potential for treatment of ethanol withdrawal-induced anxiety-like symptoms.

Effects of ritanserin on ethanol withdrawal-induced anxiety in rats

This study investigated the ability of ritanserin, a 5-HT2 antagonist, to modify ethanol withdrawal (EW) symptoms in two animal models of anxiety: the elevated plus-maze (EPM) and the pentylenetetrazol (PTZ) discrimination assay. Long-Evans hooded rats were given a nutritionally balanced liquid diet containing 4.5% ethanol for 10 days. Twelve hours after removal of the ethanol diet, rats were tested in the EPM. A significant reduction in the open-arm activity and the number of total arm entries was observed, which is indicative of EW. Acute ritanserin (0.16-0.64 mg/kg, i.p., 60 min) had no effect on EW-induced anxiety-like behavior on the EPM. Ritanserin (0.08-0.64 mg/kg, i.p., b.i.d. 12 h) administered concurrently with the last 5 days of ethanol diet produced an increase in the time spent on the open arms of the EPM and reversed the EW-induced reduction in total arm entries. Rats trained to discriminate between saline and PTZ (an anxiogenic drug), selected the PTZ lever during EW. Chronic ritanserin (0.32 mg/kg, i.p., b.i.d. ) did not block PTZ lever responding during EW. On the rotorod, ritanserin (0.32 mg/kg, i.p.) increased the motor incoordination induced by ethanol. In conclusion, coadministration of ritanserin with ethanol prevented the development of EW-induced anxiety as measured by the EPM, but not in the PTZ drug discrimination.

Sex differences in the discriminative stimulus effects of m-chlorophenylpiperazine and ethanol withdrawal

RATIONALE

The serotonergic system plays a role in regulation of anxiety and ethanol withdrawal (EW). Nevertheless, few studies have assessed sex differences in serotonergic effects on EW.

OBJECTIVES

This study examined sex differences in the anxiogenic stimuli induced by a serotonin (5-HT)(1b,2) agonist, meta-chlorophenylpiperazine (mCPP), prior to ethanol and during EW.

METHODS

Gonadectomized or sham-operated adult male and female rats and 17beta-estradiol (2.5 mg, 21-day release, s.c.) -replaced ovariectomized (OVX) rats were trained to discriminate mCPP (1.2 mg/kg, i.p.) from saline in a two-lever choice task for food. Latency to the first lever press and mCPP lever selection were measured following mCPP (0-1.2 mg/kg). Rats then received chronic ethanol-containing liquid diet (6.5%) for 10 days and were tested for mCPP lever selection 12 h and 36 h after removal of ethanol.

RESULTS

Fewer sham female and beta-estradiol-replaced OVX rats selected the mCPP lever than male or OVX rats, and showed an increased initiation latency after mCPP injection. During EW (12 h and 36 h), fewer sham female and beta-estradiol-replaced OVX rats responded on the mCPP-lever after saline injection as well as after mCPP challenge than male or OVX rats. Castration did not alter any response of male rats to mCPP.

CONCLUSIONS

(1) mCPP discrimination is a useful measure of EW in male and female rats; and (2) sham female and beta-estradiol-replaced OVX rats are less sensitive to the discriminative stimulus prior to and during EW, but more sensitive to impaired behavioral initiation induced by mCPP than male or OVX rats.

Sex differences in nicotine substitution to a pentylenetetrazol discriminative stimulus during ethanol withdrawal in rats

RATIONALE

Nicotine and ethanol are frequently co-abused in men and women, but few studies compare common stimulus effects produced by these substances between males and females.

OBJECTIVES

This study compared the anxiety-like behavior induced by nicotine prior to and during ethanol withdrawal in intact male, sham-operated female, and ovariectomized (OVX) rats.

METHODS

Using an animal model of anxiety, the pentylenetetrazol (PTZ) drug-discrimination assay, rats were trained to discriminate PTZ (16 mg/kg, i.p.) from saline and were subjected to the following tests: (1) PTZ-lever selection at 12 h after termination of ethanol diet (4.5% for 10 days); (2) dose-response tests for nicotine (0.08-1.3 mg/kg) prior to ethanol and 1.5, 6, and 7 days after ethanol withdrawal.

RESULTS

(1) During acute ethanol withdrawal (12 h), more male rats (43.4%) responded on the PTZ lever than OVX (29%) or sham female (15.3%) rats. (2) For nicotine dose-response tests, more male rats (70%) selected the PTZ lever than OVX (37.5%) or sham female (50%) rats prior to ethanol. At 1.5 days, nicotine fully generalized to the PTZ stimulus in male (100%) and OVX (90%), but only partially in sham female (50%) rats. At 6 days and 7 days after ethanol withdrawal, the PTZ-lever selection decreased, but more male rats (78%) tended to respond on a PTZ lever than OVX (63.6%) or sham female rats (62.5%).

CONCLUSIONS

Acute nicotine produces anxiety-like behavior similar to that of PTZ in male and female rats, and this effect of nicotine is intensified during ethanol withdrawal in male and OVX rats, but not in sham female rats.

Effects of NMDA receptor blockers on cocaine-stimulated locomotor activity in mice

Effects of MK-801 and ketamine, N-methyl-D-aspartate (NMDA) receptor blockers, on cocaine-stimulated locomotor activity were investigated in male Swiss-Webster mice. MK-801 (0.25, 0.5, 1.0 and 2.5 mg/kg), ketamine (10, 25 and 50 mg/kg) or saline was injected 20 min before cocaine (5, 10 and 20 mg/kg i.p.). Locomotor activity was measured for 30 min immediately following cocaine treatment. All doses of the drugs were also tested for ability to depress or stimulate locomotor activity in the naive (no cocaine-treated) mice. Cocaine produced a dose-dependent increase in locomotor activity that was blocked dose-dependently by MK-801 or ketamine. The blockade by MK-801 was more prominent than by ketamine. Our results may suggest that cocaine-induced locomotor stimulation in mice is modulated via NMDA receptor mediated mechanisms.

Stress induced phosphate solubilization in bacteria isolated from alkaline soils

Phosphate solubilizing bacteria NBRI0603, NBRI2601, NBRI3246 and NBRI4003 were isolated from the rhizosphere of chickpea and alkaline soils. All four strains demonstrated diverse levels of phosphate solubilization activity under in vitro conditions in the presence of various carbon and nitrogen sources. Acid production may have contributed to phosphate solubilization, but was not the only reason for phosphate release into the medium. Among the four strains, NBRI2601 was the most efficient strain in terms of its capability to solubilize phosphorus in the presence of 10% salt, pH 12, or 45 degrees C. The strains showed varied levels of phosphate solubilization when the effects of different sources of nitrogen were examined during growth. The presence of low levels of Ca(2+) and EDTA in the medium enhanced phosphate solubilization.

Effects of NMDA antagonists on ethanol-withdrawal induced "anxiety" in the elevated plus maze

The anxiolytic effects of NMDA antagonists during ethanol withdrawal were assessed in Long-Evans rats. Anxiety was measured by the elevated plus maze. Male rats were exposed to ethanol (6.5%) in a liquid diet for 10 days. Behavioral testing took place 12 h after withdrawal of ethanol. The competitive NMDA antagonists, AP-7 (0.02-0.32 mg/kg) and CGP-37849 (0.64-10 mg/kg), at least partially reversed the anxiety-like effects induced by withdrawal from ethanol. Both drugs produced a small increase in total arm entries, and a much larger increase in the percentage of open arm entries. AP-7, but not CGP-37849, also increased the percentage of open arm time. In contrast, the NMDA channel blocker, dizocilpine (MK-801; 0.08-0.32 mg/kg), produced only a small increase in the percentage of open arm entries and of open arm time. HA-966, a glycine-site antagonist, also failed to produce changes in ethanol withdrawal induced changes in anxiety at the doses tested. These results suggest that competitive NMDA antagonists may be useful for reduction of signs of anxiety during ethanol withdrawal.

Sex differences in the pentylenetetrazol-like stimulus induced by ethanol withdrawal

This study investigated sex differences in responding to the pentylenetetrazol (PTZ, a gamma-aminobutyric acid A antagonist) discriminative stimulus and to substitution to PTZ during ethanol withdrawal. The PTZ stimulus has served as an anxiogenic stimulus in numerous studies. Adult male and female rats were trained to discriminate PTZ (16 mg/kg i.p.) from saline in a two-lever food-reinforced task. They were then gonadectomized or sham-operated. Ovariectomized (OVX) rats were also tested during 17beta-estradiol (2.5 mg, 21 days release, s.c.) replacement. The PTZ dose response (0-16 mg/kg i.p.) was tested in all groups. In general, fewer females than males responded to PTZ. Diazepam (DZP; 0-10 mg/kg i.p.) injected before PTZ (16 mg/kg) decreased the number of rats selecting the PTZ lever. This effect was greater in sham female and estradiol-replaced-OVX rats than in male or OVX rats. Rats then received chronic ethanol diet (6.5%) for 10 days. During ethanol withdrawal (12 h after termination of the ethanol diet), they were tested for PTZ lever selection. PTZ lever selection differed between groups: sham or castrated male rats > OVX > sham female or estradiol-replaced-OVX rats. In sham female rats, estradiol concentrations showed a cyclic pattern with an estradiol surge that did not influence their PTZ discrimination performance. After i.p. injection of ethanol (2 g/kg), blood ethanol concentrations were not different in male and female rats. These findings suggest that 1) female rats are less sensitive to the anxiogenic effects of PTZ; 2) female rats are less sensitive to the anxiogenic effects of ethanol withdrawal; and 3) estrogen plays some role in mediation of these sex differences.

The effects of adenosine ligands R-PIA and CPT on ethanol withdrawal

The potential anxiogenic or anxiolytic effects of R(-)-N6-(2-phenylisopropyl)adenosine (R-PIA), an adenosine agonist, and 8-cyclopentyl-1,3,dimethylxanthine (CPT), an adenosine antagonist, were tested during chronic exposure to ethanol and to ethanol-induced withdrawal in rats. Effects on anxiety were measured by the elevated plus maze and dark-light box. Ethanol consumption and preference was tested in an additional experiment. In testing of elevated plus maze performance during withdrawal from ethanol, R-PIA produced no change in the anxiety-related behaviors of total arm entries and percent open arm entries, but produced a significant decrease in percent open arm time. CPT produced at least partial recovery from the anxiogenic effects of ethanol withdrawal on all three measures of elevated plus maze performance, although peak effects were seen at the intermediate dose of CPT (0.08 mg/kg) for total arm entries and percent open arm time. CPT also showed anxiolytic effects at low to intermediate doses (0.04, 0.08 mg/kg) in the dark-light box. CPT did not reduce the preference for ethanol over water or the total consumption of ethanol over a range of ethanol doses. In summary, the adenosine agonist, R-PIA, exacerbated the effects of ethanol withdrawal, whereas the adenosine antagonist, CPT, at least partially blocked the anxiogenic effects produced by ethanol withdrawal. These results suggest that adenosine antagonists, at least at some doses, may be useful for ameliorating the anxiogenic effects produced by ethanol withdrawal, although it does not appear useful for reducing consumption.

Discrete analysis of serum uric acid with immobilized uricase and peroxidase

Commercially available uricase and peroxidase have been immobilized onto alkylamine glass and arylamine glass beads respectively. A discrete method has been developed to determine uric acid in serum using immobilized uricase and peroxidase. The method is based on generation of H2O2 from serum uric acid by immobilized uricase and its measurement by a colour reaction catalyzed by immobilized peroxidase. The minimum detection limit of the method was 8 microg/0.1 ml sample. The mean analytical recovery of added uric acid in serum was 87.5%. The within and between assay coefficient of variation (C.V.) were <6.58% and <10.77% respectively. The serum uric acid in apparently healthy adults and persons suffering from different disease was found to be 25-55 microg/ml, 32+/-2.25 (range, mean+/-S.D.) and 55-200 microg/ml; 52+/-6.4 (range, mean+/-S.D.) respectively by our method. A good correlation (r = 0.8170) was obtained between the serum urate values by this method and with those obtained by commercial Enzo-kit method.

Chronic hypoxia differentially alters the responses of pulmonary arteries and veins to endothelin-1 and other agents

The effects of chronic hypoxia on the responses of rat large pulmonary arteries and veins to vasoactive agents have been examined. Endothelin-1-induced contractions of pulmonary arteries and pulmonary veins were reduced by chronic hypoxia. In contrast, chronic hypoxia augmented sarafotoxin 6c-induced contractile responses in pulmonary veins but not in pulmonary arteries. Chronic hypoxia augmented the constrictor effect of phenylephrine in pulmonary arteries, but not in pulmonary veins. The thromboxane receptor agonist, U46619 (9,11-dideoxy-9alpha,11alpha-epoxy-methanoprostaglandin++ + f2alpha) contracted pulmonary arteries and pulmonary veins, and although maximal responses were not altered in chronically hypoxic preparations, the EC50 value in pulmonary arteries was increased following chronic hypoxia. The relaxant effects of acetylcholine and isoprenaline on pulmonary arteries were potentiated by chronic hypoxia. In contrast, ionomycin-mediated relaxations of pulmonary arteries and pulmonary veins were reduced, while sodium nitroprusside-induced relaxation of pulmonary arteries and veins were not altered by chronic hypoxia. Previous studied have looked primarily at the effects of chronic hypoxia on pulmonary arteries. This data provides evidence that chronic hypoxia also causes selective changes in the reactivity of large pulmonary veins.

Estimating age-related changes in psychomotor function: influence of practice and of level of caloric intake in different genotypes

This article presents a discussion of some key considerations in the measurement of age-related changes in psychomotor function of mice. We illustrate that "standard" measures of psychomotor performance, such as running speed on a rotorod task, are highly sensitive to practice effects. Examples are cited in which failure to assess practice effects can influence conclusions regarding the magnitude and rate of change in psychomotor capacity as a function of age. A second set of examples is focused on estimating the effect of an experimental intervention, caloric restriction, on age-related changes in psychomotor performance. These examples show that psychomotor performance at a given age may vary directly, and reversibly, with the level of caloric intake. Independent of such reversible effects, the level of caloric intake can also modulate the rate of change in capacity as a function of age. It is concluded that reversible, short-term effects must be considered in estimating the effect of an experimental intervention on the rate of age-associated change in psychomotor function.

Effects of ethanol and ethanol withdrawal on nociception in rats

The effect of acute and chronic administration of ethanol and ethanol withdrawal on a radiant heat tail-flick assay of nociception was examined in rats. Acute administration of ethanol (2.0 g/kg, i.p.) produced peak antinociception (68% of maximum) by 30 min, and effects were gone by 120 min. Cumulative doses of ethanol (0.5-2.0 g/kg, i.p.) produced dose-dependent increases in latencies to 49% of maximum. During chronic administration, a liquid diet containing ethanol (6.5%) was given for 10 days. Tail-flick latencies were measured on day 0 (baseline), day 2, 4, 6, 8, and 10 of chronic ethanol and at 3, 6, 12, and 36 hr after removal of ethanol. To test for behavioral tolerance, both between- and within-group designs were used. In both between- and within-group experiments, the antinociceptive effects of chronic ethanol peaked by day 4 of exposure to the liquid diet, and tolerance developed by day 10. When the liquid diet was removed, hyperalgesia was detected at 6 and 12 hr after withdrawal, and was gone by 36 hr after withdrawal. When cumulative doses of ethanol (0.5-2.0 g/kg) were administered starting 12 hr after withdrawal, ethanol (0.5 g/kg) fully reversed the hyperalgesia induced by ethanol withdrawal, even though this dose was without antinociceptive effect in the absence of withdrawal. Higher doses of ethanol during ethanol withdrawal did not increase tail-flick latencies over baseline. In summary: (1) ethanol produces antinociception when administered acutely or chronically; (2) tolerance to the antinociceptive effects develops during chronic administration; (3) ethanol withdrawal induced hyperalgesia, which was reversed by ethanol; and (4) repeated testing did not produce behavioral tolerance.

Evidence for oxygenation-induced endothelin release from isolated lungs of chronically hypoxic rats

In lungs from chronically hypoxic (CH, 3 weeks at 10% inspired O2) rats, oxygenation (20% O2, 5% CO2, 75% N2; PO2 121 mmHg) of the perfusate increases pulmonary perfusion pressure (PPP) and lung weight (LW). Hypoxic perfusate (95% N2, 5% CO2; PO2 5.5 mmHg) had no effect on PPP in lungs from CH rats. Indomethacin and nitro-L-arginine (L-NOARG) augmented the oxygen-induced increase in PPP. In contrast, the free radical scavengers superoxide dismutase (SOD) plus catalase delayed the onset of oxygen-induced vasoconstriction, while the endothelin (ET)B receptor antagonist BQ788 inhibited it. The ET(A) receptor antagonist BQ123 did not affect the PPP changes. This suggests a role for endogenous endothelins and ET(B) receptors in mediating the oxygenation-induced pulmonary vasoconstriction. Indomethacin had no effect on oxygen-induced lung weight (LW) changes while BQ788 and L-NOARG reduced the LW increase. This evidence shows that ET(B) receptor activation and NO generation are involved in the LW changes. In conclusion, oxygenation of the perfusate in isolated lungs from CH rats leads to pulmonary vasoconstriction which involves endothelins and activation of ET(B) receptors. In addition, increased NO production associated with ET(B) receptor activation is the prime stimulus for observed LW increase.

Effects of tumour necrosis factor-alpha on left ventricular function in the rat isolated perfused heart: possible mechanisms for a decline in cardiac function

1. The cardiac depressant actions of TNF were investigated in the isolated perfused rat heart under constant flow (10 ml min(-1)) and constant pressure (70 mmHg) conditions, using a recirculating (50 ml) mode of perfusion. 2. Under constant flow conditions TNF (20 ng ml(-1)) caused an early (< 25 min) decrease in left ventricular developed pressure (LVDP), which was maintained for 90 min (LVDP after 90 min: control vs TNF; 110 +/- 4 vs 82 +/- 10 mmHg, P < 0.01). 3. The depression in cardiac function seen with TNF under constant flow conditions, was blocked by the ceramidase inhibitor N-oleoylethanolamine (NOE), 1 microM, (LVDP after 90 min: TNF vs TNF with NOE; 82 +/- 10 vs 11 +/- 5 mmHg, P < 0.05). 4. In hearts perfused at constant pressure, TNF caused a decrease in coronary flow rate (change in flow 20 min after TNF: control vs TNF; -3.0 +/- 0.9 vs -8.7 +/- 1.2 ml min(-1), P < 0.01). This was paralleled by a negative inotropic effect (change in LVDP 20 min after TNF: control vs TNF; -17 +/- 7 vs -46 +/- 6 mmHg, P < 0.01). The decline in function was more rapid and more severe than that seen under conditions of constant flow. 5. These data indicate that cardiac function can be disrupted by TNF on two levels, firstly via a direct, ceramidase dependant negative inotropic effect, and secondly via an indirect coronary vasoconstriction.

Lymphedema of the lower extremity as a complication of local burns

Lymphedema of an extremity is a rare complication of local burns, due to intact deep lymphatics. Here we present a case of delayed lymphedema of the foot, developing due to deep scarring after local burns.

Pharmacological treatment of alcoholism

1. Pharmacological treatments are effective as part of a treatment plan that includes substantial education, psychological therapy and social support. This paper reviews recent literature on animal models of and treatment for alcohol abuse under seven categories: agents to block craving or reduce alcohol intake, agents to induce aversion to alcohol, agents to treat acute alcohol withdrawal, agents to treat protracted alcohol withdrawal, agents to diminish drinking by treating associated psychiatric pathology, agents to decrease drinking by treating associated drug abuse, and agents to induce sobriety in intoxicated individuals. 2. The benzodiazepines provide safe and effective treatment for detoxification, although current research focuses on finding drugs with a smaller likelihood of dependence. As yet, there are no drugs that effectively reverse the intoxicating effects of alcohol. 3. Currently, only two major groups of drugs that are relatively safe have shown any effect at reducing alcohol consumption: aversives such as disulfiram, and opioid antagonists such as naltrexone. 4. Finally, it is important to customize therapy for each patient rather than putting everyone through a standard treatment plan, especially in regards to the use of antidepressant or antipsychotic medications. Tailoring the program to the patient's needs dramatically improves the outcome of therapy and reduces the risk of adverse effects.

A discriminative stimulus produced by 1-(3-chlorophenyl)-piperazine (mCPP) as a putative animal model of anxiety

1. This study compares behavioral responses to serotonergic (5HT) agonists and pentylenetetrazol (PTZ) in two behavioral paradigms used as animal models of anxiety. PTZ and mCPP were compared for behavioral effects in elevated plus-maze and interoceptive discriminative stimuli they produce. 2. PTZ is a known anxiogenic drug. The discriminative stimuli of mCPP were selected for comparison because this drug produces "anxiety" in human subjects and "anxiety-like" behaviors in rats, and is a potent agonist at 5HT1B/2C receptors and a partial agonist at 5HT2A receptors. 3. In rats trained to discriminate mCPP (1.4 mg/kg, training dose) from saline, PTZ substituted for the mCPP suggesting the "anxiety-like" properties of the mCPP stimulus. The mCPP stimulus was blocked in a dose-related manner by methysergide, a 5HT2A/2C antagonist but not by the anxiolytic diazepam. TFMPP (a 5HT agonist) and DOI (a 5HT2A/2C agonist) substituted for mCPP, but 1-NP (a 5HT1 agonist and 5HT2C/2A antagonist) did not. 4. In animals trained to discriminate PTZ (16 mg/kg) from saline, mCPP and DOI substituted for PTZ, while TFMPP and 1-NP do not. 5. In the elevated plus maze, time spent on the open arms was reduced by mCPP, DOI and PTZ but there was no significant dose effect of TFMPP, or 1-NP. 6. Methysergide blocked the "anxiety-like" behavior in the EPM. 7. These data suggest that the discriminative stimuli produced by mCPP are based upon its selective actions on 5HT receptors and their use in behavioral pharmacology may offer another tool in studying pharmacology of 5HT based anxiogenic and anxiolytic drugs.

Vitamin E status in protein energy malnutrition

Serum vitamin E and cholesterol concentrations were measured in 50 children with protein energy malnutrition (PEM) and results were compared with a group of 50 normal controls. Mean serum vitamin E concentration as well as vitamin E/cholesterol ratio were found to be reduced in children with PEM while their mean serum cholesterol level was not significantly different from the control group. Data suggest that the reduced levels of serum vitamin E in PEM may be a result of malnutrition per se.