Opiate receptor subtype binding in gerbil hippocampus is altered by forebrain ischemia

A role for endogenous opioids in trauma-induced brain injury has been supported by pharmacological studies. The present series of experiments were initiated to extend these observations by measuring opiate receptor subtype binding in gerbil hippocampus following 7 days recovery from a 10 min ischemic insult. Quantitative in vitro autoradiography was utilized to measure mu [( 3H]DAGO), kappa [( 3H]bremazocine + 10 microM morphiceptin + 100 nM DSLET), delta [( 3H]DSLET + 10 microM morphiceptin) and lambda [( 3H]naloxone + 300 nM diprenorphine) binding. While ischemic tissue samples at the level of the dorsal hippocampus showed complete loss of CA1 pyramidal cells, we observed no significant alterations in mu or delta binding suggesting a non-pyramidal cell localization of these receptors. Kappa binding decreased significantly to 88% of control in the CA1 and CA3 regions while lambda binding in the stratum lucidum (CA3) increased to 165% of control. Our results show that opiate receptor subtypes are differentially affected by an ischemic insult.     

An outbreak of watermelon-borne pesticide toxicity.

The largest reported United States outbreak of illness caused by a foodborne pesticide was due to aldicarb-contaminated watermelons. In Oregon, where the first episodes of toxicity were reported, 264 reports were received, and 61 definite cases were identified. Residues of aldicarb, a cholinesterase inhibitor, were found in 10 of 16 tested melons which had been eaten by persons meeting the case definition. The outbreak demonstrates the need for enhanced physician vigilance with respect to anticholinesterase intoxication. It also demonstrates the value of an established system for reporting of unusual illness to public health officials.     

Haemodynamic effects of rectal methohexitone for induction of anaesthesia in children

Pulsed Doppler and two-dimensional echocardiography were used to determine the haemodynamic effects of rectal methohexitone in 12 children 32.4 +/- 3.8 months old and weighing 13.3 +/- 1.1 kg (mean +/- SEM). Heart rate, blood pressure and echocardiographic measurements of cardiac output, stroke volume and left ventricular end-diastolic and end-systolic volumes were obtained prior to the induction of anaesthesia. Anaesthesia was induced with 25 mg.kg-1 two per cent rectal methohexitone. Immediately following the onset of sleep all cardiovascular measurements were repeated. Following the induction of anaesthesia with rectal methohexitone there was a significant increase in heart rate. Blood pressure, cardiac index, stroke volume and ejection fraction were unchanged. It is concluded that rectal administration of two per cent methohexitone for the induction of anaesthesia in healthy paediatric patients has minimal haemodynamic effect.     

Acetylator genotype-dependent metabolic activation of carcinogenic N-hydroxyarylamines by S-acetyl coenzyme A-dependent enzymes of inbred hamster tissue cytosols: relationship to arylamine N-acetyltransferase

A genetic polymorphism in S-acetyl coenzyme A (AcCoA)-dependentN-acetyltransferase has been associated with a differentialrisk for certain cancers in humans. In this study, several tissuesfrom the inbred Syrian hamster with a genetically defined AcCoA-dependentN-acetyltransferase polymorphism (homozygous rapid acetylator,Bio. 87.20; homozygous slow acetylator, Bio. 82.73/H; and heterozygousacetylator, Bio. 87.20 x Bio. 82.73/H F₁), were investigatedfor the relationship of arylamine N-acetyltransferase to theAcCoA-dependent metabolic activation of carcinogenic N-hydroxy(N-OH)-arylamines to bind to DNA (O-acetyltransferase). Thelevels of both 2-aminofluorene (AF) N-acetyltransferase andN-OH-AF O-acetyltransferase activity reflected the N-acetylatorgenotype in liver, intestine, kidney and lung cytosols. A significantacetylator gene—dose response for AF N-acetyltransferaseand N-OH-AF O-acetyltransferase activities was observed in liverand lung cytosols. In contrast, acetylator genotype was notconsistently expressed for the AcCoA-dependent N-acetylationof 4-aminobiphenyl (ABP), nor for the AcCoA-dependent metabolicactivation of N-OH ABP and N-OH-3,2'-dimethyl-4-aminobiphenylin these me tissue cytosols. Two peaks of acetyltransferaseactivity were partially purified by ion exchange FPLC chromatographyfrom the hepatic cytosol of both the homozygous rapid and homozygousslow acetylator hamster. In contrast to unfractionated cytosol,the isozyme(s) eluting first clearly demonstrated levels ofAcCoA-dependent arylamine N-acetyltransferase and N-OH-arylamineO-acetyltransferase activities that were consistent with N-acetylatorgenotype (polymorphic) for all substrates tested. In contrast,the slower eluting isozyme(s) in each acetylator cytosol showedlevels of AcCoA-dependent N-and O-acetyltransferase activitiesthat did not vary with N-acetylator genotype (monomorphic).The AcCoA-dependent O-acetyltransferase activity of both themonomorphic and polymorphic peaks was paraoxon resistant. Thesestudies demonstrate acetylator genotype-dependent control ofAcCoA-dependent metabolic activation of N-OH-arylamines(O-acetylation)by polymorphic isozyme(s) similar to that for AcCoA-dependentN-acetylation of arylamines in the hamster. The polymorphicgenetic control of N-OH arylamine O-acetyltransferase may bean important risk factor for arylamine-induced cancer, in thosespecies and tissues expressing appreciable levels of O-acetyltransferaseactivity.     

Management of postoperative mediastinitis in infants and children by muscle flap rotation

Between July 1, 1976, and June 30, 1986, at the Henrietta Egleston Hospital for Children, 2,242 infants and children underwent palliation or repair of a congenital heart defect. Twenty-one (0.94%) of these patients developed mediastinitis following a median sternotomy. Nineteen of these twenty-one patients had required cardiopulmonary bypass. All patients had positive mediastinal cultures. The first 8 patients were managed traditionally by debridement and irrigation. Three of these patients suffered serious metabolic complications related to the povidone-iodine irrigant, which resulted in 1 death. Another patient died from persistent sepsis following debridement. Subsequently, 13 patients were managed by early debridement and rotation of the pectoralis major or rectus abdominis muscle flaps, or both. Following muscle flap rotation and early wound closure, 2 patients had subsequent incisional complications. One patient had incisional dehiscence and 1 had a superficial skin separation. Two deaths in this group, 28 and 51 days, respectively, following muscle flap rotation, resulted from nonincisional problems in patients with healed median sternotomies. The group having muscle flap rotation required a significantly shorter duration of postoperative ventilatory support (3.2 versus 24 days, p less than 0.05) and a significantly shorter confinement in the intensive care unit (6.2 versus 33 days, p less than 0.01). Also, the physiological and physical trauma of continued wound care in the awake child was minimized in the group with muscle flap rotation.     

Rescreening of a group at high risk for colorectal neoplasia using immunochemical tests for faecal occult blood

The results of a screening programme for colorectal neoplasia in a high risk group using an immunochemical test for blood has been reported recently. This test is known as the faecal human haemoglobin (FHH) test. This paper reports the results of rescreening this group after an interval of 1-2 years. The FHH test was compared with a paper disc method. All individuals with positive tests were investigated and those with negative tests were offered investigation. The results confirm the value of the FHH test in screening a high risk group: 19 individuals in 1,153 participants were found to have a significant neoplasm (1.6%). The predictive value of the test for a significant neoplasm was 42%. A false negative rate of 2.6% was found, all lesions being benign. It appears to be more reliable than the paper disc method but the differences do not reach statistical significance. The FHH test is recommended for screening the general population over the age of 40 years, with rescreening annually.