Evidence for the involvement of the nitric oxide-cGMP pathway in the antinociception of morphine in the formalin test

The effect of inhibition of nitric oxide synthesis and guanylate cyclase on the peripheral antinociceptive effect of morphine was assessed by using the formalin test in the rat. Saline, N(G)-monomethyl-L-arginine, a nitric oxide synthesis inhibitor (50 microg) and methylene blue, a guanylate cyclase inhibitor (500 microg), did not exhibit any antinociceptive activity. However, morphine (10 microg) produced a significant antinociceptive effect in phases 2a and 2b, which was reduced by pretreatment with either N(G)-monomethyl-L-arginine or methylene blue. These results suggest that the local administration of morphine induces antinociception by the activation of the L-arginine-nitric oxide-cGMP pathway.     

Epitopes for thyroid stimulating and blocking autoantibodies on the extracellular domain of the human thyrotropin receptor

The majority (97%) of functional epitopes for stimulating thyrotropin receptor (TSHR) antibodies (stimulating TSHRAbs) in a large cohort (n = 59) of Japanese Graves' patients exists on the N-terminal region of the extracellular domain of TSHR, between residues 25 and 165 numbering from the methionine start site. This was determined by measuring the loss of stimulating activity in the Cos-7 cells transfected with TSHR/lutropin-choriogonadotropin receptor (LH-CGR) chimeras wherein TSHR residues 89-165 (Mc2) or 8-165 (Mc1 + 2) are replaced by comparable LH-CGR residues. There is no comparable loss when stimulating TSHRAb activity is measured in an Mc4 chimera, wherein TSHR residues 261 to 370 are replaced. In contrast, immunoglobulin (IgG) preparations from 35 patients with Hashimoto's disease or idiopathic myxedema, who have blocking TSHRAbs causing hypothyroidism, loose blocking TSHRAb activity in the Mc4 chimera, but not the Mc2 or Mc1 + 2 chimeras. Thus, in a large population of Japanese patients with autoimmune thyroid disease caused by TSHR autoantibodies, the major functional epitope for stimulating TSHRAbs is on the N-terminal portion of the TSHR extracellular domain, whereas that for blocking TSHRAbs is on the C-terminal portion of the extracellular domain. To further evaluate the nature of the critical functional epitope between residues 90 to 165, we divided this region approximately in half, creating chimeras Mc2a and Mc2b with, respectively, residues 90-124 or 125-165 replaced by comparable LH-CGR residues. IgGs from all patients tested lost significant stimulating activity using the Mc2a and Mc2b chimeras; however, when present, residual stimulating TSHRAb activity was evident on one or the other half of the region or on both halves, indicating that both segments are required for expression of the stimulating TSHRAb epitope within residues 90-165. Finally, we have identified a complex epitope involving both the N- and C-terminal portion of the extracellular domain that appears to account for the small fraction of stimulating TSHRAbs whose activity is not solely dependent on residues 25 to 165. Thus, using chimeras Mc1 + 2 + 4, with TSHR residues 8-165 and 261-370 substituted, or chimera Mc1 + 2 + 3 + 4, with residues 8-370 substituted, as well as Mc2, Mc1 + 2, and Mc4, we show that the Graves' IgGs which maintain stimulating TSHRAb activity when residues 8-165 of the TSHR are replaced by LH-CGR residues have an epitope involving residues 90-165 and the immunogenic 15mer peptide (YYVFFEEQEDEIIGF), residues, 352-366. Because that peptide can decrease the stimulating TSHRAb activity of these Graves IgGs in assays with the Mc2 chimera alone, we speculate that this complex epitope may be important in an epitope spreading process involved in the formation of stimulating TSHRAbs.     

Mouse lung epithelial cell lines--tools for the study of differentiation and the neoplastic phenotype

Several dozen lung epithelial cell lines have been established in culture over the past 20 years from normal lung explants and their spontaneous transformants, and from lung tumors that arose spontaneously or were induced with chemicals, viruses, or oncogenic transgenes. To provide information from which to choose appropriate lines for investigating problems in lung cell biology and pulmonary neoplasia, this review describes the origins of these lines and some of their characteristics. These include growth, morphology, tumorigenicity, ability to metastasize, xenobiotic metabolism, mutational status, signal transducing activities, cytogenetics, ability to form domes, and electric conductance. In addition to collecting this information in a single place for the first time, we describe previously unpublished apoptosis features of some of these lines. An increasing number of investigations are beginning to use these lines and this review contains references into 1997.     

A study examining intravenous ethanol-conditioned place preference in C57BL/6J mice

The reinforcing effects of intravenous (I.V.) ethanol were examined in C57BL/6J (C57) mice with a conditioned-place-preference (CPP) paradigm. Before CPP testing, adult mice underwent jugular catheterization. On the following day, subjects were acclimated to a two-compartment CPP chamber. A 15-min nondrug pretest was conducted to determine compartment preference. For the treatment group, I.V. ethanol [30% (v/v), 3.4 microl/min, 25 min] was paired with the nonpreferred compartment, whereas I.V. saline was paired with the preferred compartment. The control group received I.V. saline in both compartments. Two conditioning sessions were conducted per day (0900 and 1500), and the order of the infusions was counterbalanced across subjects. The drug-free posttest was identical to the pretest, except that it occurred on the day after the final drug/compartment pairing. The entire procedure required 6 days. After just two pairings with ethanol, with a cumulative ethanol dose of only 0.82 g/kg/day, significant CPP was noted in the treatment group, whereas no change in compartment preference was noted for the control group. A separate group of C57 mice were trained to discriminate intraperitoneal ethanol (1.5 g/kg) from saline using a two-lever drug discrimination paradigm. After training was complete, these mice also underwent jugular catheterization. Substitution testing was conducted with I.V. ethanol [30% (v/v), 6.4 microl/min, 12 min] and saline. The results indicate that the subjective effects of ethanol did not differ according to the route of administration. Together, these experiments provide evidence that ethanol is rewarding for C57 mice, as indexed by ethanol CPP, and that the subjective effects of intravenously and intraperitoneally administered ethanol are similar.     

Estimation of genetic parameters for growth, feed consumption, and conformation traits for double-muscled Belgian blue bulls performance-tested in Belgium

For 1,442 Belgian Blue bulls performance-tested at the Centre de Sélection de la Race Blanc-Bleue Belge, nine traits were observed: height at withers at 7 mo, height at withers at 13 mo, weight at 7 mo, weight at 13 mo, average feed consumption of concentrates, average daily gain, average feed consumption of concentrates per average daily gain, average feed consumption of concentrates per mean metabolic weight, and price per kilogram of live weight. This price is based on muscle conformation and is therefore used as muscle conformation score. Restricted maximum likelihood with a derivative-free algorithm was used to estimate (co)variance components because there were different models and missing values per trait. Estimates of heritabilities were above .50 except for average feed consumption per average daily gain (.16) and average feed consumption per mean metabolic weight (.33). Estimates of genetic and phenotypic correlations between height at withers and weight traits were positive and moderate to high. Average daily gain showed a negative genetic correlation with weight at 7 mo (-.68) but had positive correlations with height at withers at 13 mo and weight at 13 mo (.22 and .43). Muscle conformation expressed as price per kilogram of live weight was related to low average feed consumption per average daily gain. Average feed consumption showed high correlations with weight at 7 mo and weight at 13 mo. Average feed consumption per average daily gain had a high negative genetic correlation with average daily gain (-.89).     

Pharmacologic atrial natriuretic peptide reduces human leg capillary filtration

Atrial natriuretic peptide (ANP) is produced and secreted by atrial cells. We measured calf capillary filtration rate with prolonged venous-occlusion plethysmography of supine healthy male subjects during pharmacologic infusion of ANP (48 pmol/kg/min for 15 min; n = 6) and during placebo infusion (n = 7). Results during infusions were compared to prior control measurements. ANP infusion increased plasma [ANP] from 30 +/- 4 to 2,568 +/- 595 pmol/l. Systemic hemoconcentration occurred during ANP infusion: mean hematocrit and plasma colloid osmotic pressure increased 4.6 and 11.3%, respectively, relative to preinfusion baseline values (p < 0.05). Mean calf filtration, however, was significantly reduced from 0.15 to 0.08 ml/100 ml/min with ANP. Heart rate increased 20% with ANP infusion, whereas blood pressure was unchanged. Calf conductance (blood flow/arterial pressure) and venous compliance were unaffected by ANP infusion. Placebo infusion had no effect relative to prior baseline control measurements. Although ANP induced systemic capillary filtration, in the calf, filtration was reduced with ANP. Therefore, pharmacologic ANP infusion enhances capillary filtration from the systemic circulation, perhaps at upper body or splanchnic sites or both, while having the opposite effect in the leg.     

Resolution of a left ureteral stone using electrohydraulic lithotripsy in a thoroughbred colt

A 3-year-old Thoroughbred colt was presented for evaluation of azotemia and anorexia. Physical examination revealed a ureterolith in the left ureter, approximately 10 cm from the bladder, which was thought to obstruct urine flow by approximately 90% when viewed cystoscopically. Ultrasonographic examination of both kidneys revealed indistinct corticomedullary junctions, and the right kidney was more hyperechoic. A percutaneous biopsy of the right kidney revealed chronic interstitial nephritis with marked interstitial medullary fibrosis. Medical therapy consisting of IV fluids, sodium chloride PO, and ammonium chloride PO was initiated. Ureteroscopic electrohydraulic lithotripsy via a perineal urethrostomy was used to successfully remove the stone. Klebsiella oxytoca, which responded to oral enrofloxacin therapy, was cultured from the urine after surgery. Azotemia resolved and the horse resumed training.     

Postmortem analysis of bone growth into porous-coated acetabular components

Microradiography, backscattered electron microscopy, and histological analysis were used to conduct a quantitative postmortem study of seven consecutively retrieved anatomical porous replacement acetabular components that had been inserted during total hip arthroplasties. Screws had been used for the initial fixation of six components. The microradiographic analysis of all seven components showed that an average (and standard deviation) of 84 +/- 9 per cent (range, 72 to 93 per cent) of the porous coating was in direct apposition to the periprosthetic bone. The backscattered electron images demonstrated that an average of 12 +/- 6 per cent (range, 4 to 21 per cent) of the space available in the porous coating was occupied by ingrown bone. The amount of bone ingrowth was not significantly different among the three zones delineated by DeLee and Charnley. Uniformity of bone growth into the porous coating suggests that the preferential loading that occurs in the superior region did not differentially affect the bone ingrowth. The present study showed that consistent bone growth into anatomical porous replacement acetabular components can be achieved.     

Trends in rates of occupational fatal injuries in the United States (1983-92)

Recent advancements in laparoscopic surgery have made laparoscopic splenectomy possible. We retrospectively compared the outcomes of laparoscopic versus open splenectomy in patients with idiopathic thrombocytopenic purpura (ITP) or beta-thalassemia. From July 1993 to July 1997, 52 patients (ITP, 43 cases; beta-thalassemia, 9 cases) underwent either laparoscopic (30 patients, 9 men, 21 women; average age, 36.9 years) or conventional open splenectomy (22 patients, 5 men, 17 women; average age, 34.3 years). The two groups were similar in terms of sex, age, diagnosis, duration of disease, preoperative platelet count, and spleen size. The mean surgical time, estimated amount of blood loss, duration of postoperative recovery, analgesic usage, and complications were compared between the two groups. Laparoscopic splenectomy was successful in 29 (97%) of the 30 patients. The mean surgical time in the laparoscopy group was longer than in the open splenectomy group (190.6 vs 113.9 minutes, p < 0.01). The laparoscopy group had earlier postoperative oral intake (15.2 vs 52.6 hours, p < 0.01), less usage of analgesics (meperidine 50 mg/unit, 1.1 vs 2.8 units, p < 0.01) and a shorter postoperative hospital stay (4.1 vs 6.8 days, p < 0.01). The estimated blood loss, incidence of accessory spleen, surgical complication rate, and recurrence rate of thrombocytopenia were similar in the two groups. Our findings show that laparoscopic splenectomy in patients with ITP or beta-thalassemia is as safe as the open approach. While laparoscopy required a longer surgical time, the recovery period was shorter, analgesic use was less, and physical discomfort was less severe.