Potentiation of proopiomelanocortin gene expression in cultured pituitary cells by benzodiazepines

BACKGROUND: Benzodiazepines are frequently used not only as a part of general anesthesia but also for the purpose of sedation during regional anesthesia. Effects of these drugs on the hypothalamic-pituitary-adrenal axis activity have been studied, but are still controversial. It is not known whether benzodiazepines affect expression of proopiomelanocortin, precursor protein of adrenocorticotropic hormone and related peptides. METHODS: AtT20PL cell line, a clone of AtT20/D16v mouse corticotroph tumor cells stably transfected with approximately 0.7 kilobases (kb) of the rat proopiomelanocortin 5' promoter-luciferase fusion gene, was used. In the presence or absence of diazepam or midazolam, cells were stimulated by corticotropin-releasing hormone (CRH) or forskolin. Proopiomelanocortin gene expression was estimated by measurement of luciferase activity. Furthermore, to study the mechanism of benzodiazepine effects, cyclic adenosine 3',5'-monophosphate (cyclic AMP) efflux was measured by enzyme immunoassay. RESULTS: Diazepam and midazolam dose-dependently increased the proopiomelanocortin gene expression induced by CRH or forskolin. The potentiating effect was not affected by benzodiazepine receptor antagonists flumazenil and PK11195, but was abolished by a cyclic AMP-dependent protein kinase inhibitor H89. Cyclic AMP efflux induced by CRH or forskolin was also enhanced by diazepam and midazolam. In the presence of isobutylmethylxanthine, a nonspecific phosphodiesterase inhibitor, potentiation of proopiomelanocortin gene expression and enhancement of cyclic AMP efflux by benzodiazepines were not observed. CONCLUSIONS: Benzodiazepines potentiate the effect of CRH or forskolin on proopiomelanocortin gene expression. The potentiating effect is not mediated by the benzodiazepine receptors, but its mechanism probably involves inhibition of phosphodiesterase.     

Stabilized subcutaneous transposition of the ulnar nerve

We treated 50 patients (average age 47.9 years) with a stabilized subcutaneous transposition of the ulnar nerve. The average follow-up period was 42.4 months. The indication was cubital tunnel syndrome in 19 patients and injuries around the elbow in 31 patients. Postoperatively, satisfactory results were obtained in all the patients, and there was no complication or aggravation of the preoperative symptoms. None of the patients experienced slipping back of the nerve to the cubital tunnel. In the 31 patients with injuries around the elbow, there was only one patient with transient aggravation of parasthaesiae in the ulnar nerve region. Stabilized subcutaneous transposition is a simple and less invasive procedure that can facilitate decompression and prevent slipping back of the nerve. This procedure also can be applied to patients with injuries around the elbow that require ulnar nerve transfer.

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Résumé Nous avons traité 50 malades (âge moyen 47.9 années) avec une transposition sous-cutanée stabilisée du nerf cubital. La durée du suivi moyen était 42.4 mois. L'indication était un syndrome du tunnel cubital chez 19 malades et une blessure autour du coude chez 31 malades. Des résultats post-opératoires satisfaisants ont été obtenus pour tous les malades, et il n'y avait aucune complication ou aggravation des symptômes pré-opératoires. Aucun des malades n'a souffert du recul du nerf cubital en arrière. Chez les 31 malades avec une blessure, seulement un patient a eu une aggravation transitoire des paresthésies dans le territoire cubital. La transposition sous-cutanée stabilisée est une procédure simple et moins envahissante qui peut faciliter la décompression et prévenir le déplacement du nerf en arrière. Cette procédure peut aussi être appliquée aux malades avec une blessure du coude qui exige un transfert cubital.

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First presented at the SICOT World Congress 2002, San Diego, California, USA     

Glutamine infusion during ischemia is detrimental in a murine gut ischemia/reperfusion model

BACKGROUND: Gut ischemia/reperfusion (I/R) frequently occurs in clinical settings as a result of disproportionate splanchnic hypoperfusion during shock. Glutamine (GLN) supplementation of total parenteral nutrition (TPN) before gut I/R improves survival after gut I/R compared with standard TPN. However, it is unknown whether GLN treatment after the occurrence of the insult is beneficial or not. The aims of this study were to examine effects of GLN infusion during gut ischemia on survival, myeloid cell (neutrophils + monocytes) activation, and vascular permeability in organs. METHODS: Male Institute of Cancer Research (ICR) mice were randomized to control and GLN groups. After IV cannulation, mice underwent 90 (experiments 1 and 2) or 60 (experiment 3) minutes of gut I/R. Control mice received normal saline infusion at 1 mL/h for 60 minutes during ischemia, whereas the GLN group was given 3% GLN solution. In experiment 1, survival rates were monitored for 72 hours (n = 25). In experiment 2, peripheral blood was obtained at 2 or 4 hours after reperfusion (n = 17). Reactive oxygen intermediate (ROI) production by myeloid cells was determined by flow cytometry using dihydrorhodamine 123 with or without phorbol myristate acetate stimulation. Expression of CD11a and CD11b on myeloid cells was also measured. Myeloperoxidase (MPO) activity in the lung was evaluated. In experiment 3, vascular permeability in organs was measured using Evans blue at 2 or 4 hours. RESULTS: In experiment 1, survival time in the GLN group was significantly reduced compared with the control group (p = .02, log-rank test). The survival rates were 92% (12/13) and 42% (5/12) for the control and GLN groups at 12 hours (p = .01) and 38% (5/13) and 0% (0/12) at 48 hours (p = .02), respectively. In experiment 2, ROI production was significantly higher in the GLN group than in the control group after PMA stimulation both at 2 and 4 hours. CD11b expression was significantly higher in the GLN group than in the control group at 4 hours. There was no difference in pulmonary MPO activity at either time point. In experiment 3, GLN infusion significantly increased hepatic vascular permeability compared with saline infusion at 4 hours. CONCLUSIONS: GLN infusion during ischemia is detrimental for survival after gut I/R. A possible mechanism is excessive priming of myeloid cells caused by GLN infusion. Timing of GLN administration is critical for outcome after gut ischemic insult.     

Mild hypothermia reduces expression of heat shock protein 60 in leukocytes from severely head-injured patients

BACKGROUND: Infectious complications are among the most serious problems that occur in severely head-injured patients treated with mild hypothermia. The mechanism underlying the susceptibility to infection has not been clarified. Heat shock protein (HSP) 60 has been reported to play an essential role in innate immunity. Thus, we conducted a study to clarify the impact of mild hypothermia on the expression of HSPs in polymorphonuclear leukocytes (PMNLs) in severely head-injured patients. METHODS: Between September 1997 and November 1999, 17 severely head-injured patients with a Glasgow Coma Scale score of 8 or less at admission in whom intracranial pressure could be maintained below 20 mm Hg by conventional therapy were randomly assigned to two treatment groups: a mild hypothermia group (HT group, nine patients) and a normothermia group (NT group, eight patients). The HT group was subjected to mild hypothermia (intracranial temperature, 34 degrees C) for 48 hours followed by rewarming at a rate of 1 degrees C per day for 3 days, whereas the NT group was subjected to normothermia (intracranial temperature, 37 degrees C) for 5 days. Blood samples were serially obtained at three time points; days 0 to 1, days 2 to 5, and days 6 to 14 after head injury. We measured the expression of HSP27, HSP60, HSP70, and HSP90 by flow cytometry. RESULTS: The two groups were similar with respect to prognostic factors, and there was no difference in clinical outcome. The expression of PMNL HSP60 in the HT group was significantly lower in all three time periods compared with that in the NT group (p < 0.05), whereas expression of the other HSPs did not differ significantly between the groups. The incidence of infectious complications was significantly increased in the HT group over that in the NT group (p < 0.05). In in vitro studies, PMNLs from 10 healthy volunteers were incubated at 37 degrees C, 34 degrees C, or 26 degrees C for 1 hour with sodium arsenite (100 micromol/L), an HSP inducer. The expression of HSP60 at 26 degrees C and 34 degrees C was significantly lower than that at 37 degrees C (p < 0.05), whereas expression of the other HSPs did not differ significantly at 26 degrees C, 34 degrees C, or 37 degrees C. CONCLUSION: Mild hypothermia reduces the expression of HSP60 in PMNLs from severely head-injured patients. Thus, mild hypothermia may suppress innate immunity.     

Metabolic effects of D-psicose in rats: studies on faecal and urinary excretion and caecal fermentation

D-psicose (D -ribo-2-hexulose), a C-3 epimer of D-fructose, is one of the "rare sugars" present in small quantities in commercial carbohydrate complex or agricultural products. We investigated the absorption and excretion of D-psicose when orally administrated (5g/kg body weight) to Wistar rats, and the fermentation of D-psicose was measured as caecal short-chain fatty acids (SCFAs) when fed to rats in controlled diets (0, 10, 20 and 30%). Urinary and faecal excretions of D-psicose over the 24 h, following a single oral administration, were 11-15% of dosage for the former and 8-13% of dosage for the latter. Serum D-psicose concentration and D-psicose in the contents of stomach and small intestines decreased progressively after administration. D-psicose in caecum contents was detected after 3h and 7h administration, but not after 1h. Rats fed on D-psicose diets showed short-chain fatty acid production with caecal hypertrophy. These results suggest that D-psicose is partly absorbable in the digestive tract and is excreted into urine and faeces. As with other poorly absorbed dietary carbohydrates, D-psicose is fermented in the caecum by intestinal microflora.     

Lumbar posterolateral fusion alone or with transpedicular instrumentation in L4--L5 degenerative spondylolisthesis

We retrospectively reviewed 57 patients with L4--L5 degenerative spondylolisthesis (L4--L5 DS) who underwent posterior decompression and posterolateral fusion of L4--L5 without (Group A) or with (Group B) transpedicular screw instrumentation at least 2 years earlier. The clinical results and fusion rate were similar between Groups A and B, that is, a 72.4% satisfactory outcome with a fusion rate of 82.8% in Group A versus 82.1% satisfactory outcome with a 92.8% fusion rate in Group B. Screw instrumentation reduced postoperative low back pain and resulted in a lordotic slip angle of L4--L5. However, in patients with radiologically excessive segmental motion showing a translational motion of 3 mm or more, flexion angulation of -5 degrees or less, and a slip angle of -5 degrees or less at the site of spondylolisthesis (L4--L5), the kyphotic slip angle (L4--L5) tended to increase after surgery. In the future, in patients with radiologically excessive segmental motion, this point should be considered, and surgical techniques should be evaluated. Our results suggest that the validity of the general addition of screw instrumentation to L4--L5 fusion for L4--L5 degenerative spondylolisthesis is low.     

Prognostic value of DNA ploidy response to chemotherapy in human osteosarcomas.

We analyzed the DNA ploidy alterations after preoperative chemotherapy in 30 patients with non-metastatic osteosarcomas of the extremities. All of the patients received intensive chemotherapy with doxorubicin, cisplatin and methotrexate as well as wide tumor resection. DNA ploidy was determined by DNA cytofluorometry using isolated and smeared cells from biopsied and resected tumors after preoperative chemotherapy. The results showed that 12 diploid and nine non-diploid osteosarcomas did not change their ploidy pattern, but nine non-diploid tumors changed to a diploid pattern with the disappearance of the aneuploid cells. The nine patients with altered ploidy tumors had a better histologic response to chemotherapy and a better prognosis than the patients with non-altered tumors especially diploid tumors (P = 0.0138). Therefore, we conclude that a decrease in aneuploid cells after chemotherapy is closely correlated with a good prognosis in half of the cases of aneuploid osteosarcoma. These results also suggest that aneuploid cells are more chemosensitive than diploid cells in human osteosarcomas.     

Prognostic significance of DNA ploidy pattern in osteosarcomas in association with chemotherapy.

In this study, we analysed the DNA ploidy of osteosarcomas at biopsy and attempted to clarify the relationship between DNA ploidy pattern and prognosis. Thirty patients with non-metastatic osteosarcoma of an extremity were studied. All underwent intensive chemotherapy with doxorubicin, cisplatin and methotrexate, in addition to wide tumor resection. DNA ploidy was detected by DNA cytofluorometry, using isolated and smeared cells of biopsied tumor tissue. Twelve tumors showed a diploid ploidy pattern and 18 showed a non-diploid pattern such as aneuploidy (15 tumors) and euploid-polyploidy (3 tumors). The event-free survival rate at 9 years was 63.5% in non-diploid osteosarcoma patients and 13.3% in diploid osteosarcoma patients. There was a statistically significant difference between the two groups (P = 0.0278). These results lead us to conclude that a non-diploid osteosarcoma may be more sensitive to chemotherapy than a diploid tumor.