Influence of continuous levels of fentanyl in rats on the mu-opioid receptor in the central nervous system

The highly potent and efficacious mu-opioid agonist fentanyl was SC infused into rats with submaximal analgesic doses (0-1.14 mumol/kg/day) continuously for 8 days, checked by the constant daily urinary recovery of intact drug (0.43 +/- 0.031% of the daily dose). Tail-flick latencies measured at 24 (day 1) and 48 h (day 2) after starting the infusion were increased in a dose-dependent fashion compared with those before the infusion (day 0). However, at day 8, the latencies were increased only weakly, not significantly, revealing tolerance to the antinociceptive activity of fentanyl. Fentanyl at all doses showed no significant effect on the capacity (Bmax) and affinity (Kd) of the mu-opioid receptor binding of DAMGO to whole brain (Bmax 126.2 +/- 3.00 fmol/mg protein, Kd 1.00 +/- 0.04 nM) and spinal cord (Bmax 48.24 +/- 2.71 fmol/mg protein, Kd 1.93 +/- 0.13 nM) membranes gained from the rats after killing them at day 8. Gpp(NH)p increased the Kd for brain and spinal cord sites by 3.09 and 2.65, respectively, independent of the fentanyl dose. The infusion with fentanyl did not after the basal and forskolin-stimulated adenylate cyclase activity in the whole brain membranes, nor did it change the inhibition of the forskolin-stimulated activity by DAMGO. It is concluded that, in rats, constant long-term body levels of highly potent mu-agonists result in a tolerant state that, however, does not produce overall changes in the parameters of their specific receptor sites in the CNS, i.e., receptor capacity and affinity, and in the events closely related to them, i.e., their regulation by GTP and of adenylate cyclase. This does not exclude such possible changes to be restricted to specific regions in the CNS.

[Simultaneous long-term measurement of duodenogastric reflux and gastroduodenal motility]

We combined a newly developed ambulatory fiberoptic system for detecting intragastric bilirubin (Bilitec 2000, Synectics Medical Inc., Sweden) with prolonged measurement of gastroduodenal motility in 10 healthy volunteers and 10 patients followed BI resection. Circadian intragastric bilirubin exposure and the total number of tremendous changes of bilirubin absorption (more than 20%, over a period of at least 5 min) were significantly increased in the BI-resected patients (P < 0.05). In patients the interdigestive motility cycle (IMC) was characterized by the appearance of several types of abnormally propagated phase III activity fronts. Of the tremendous increases of bilirubin absorption in the patient group, 90.1% were associated with abnormally propagated phase III activity fronts. In cases of increased duodenogastric reflux, the combination of ambulatory intragastric bilirubin measurement and long-term manometry seems to be feasible to assess motility and reflux simultaneously.

Correlations between endotoxin, interferon-gamma, biopterin and serum phospholipase A2-activities during lethal gram negative sepsis in rats

OBJECTIVE

To establish a standardised reproducible animal model of intraperitoneal sepsis, and to investigate early immunoserological responses to find a mediator-based system for evaluation and grading of diffuse peritonitis in patients

DESIGN

Prospective experimental study

SETTING

4 Teaching hospitals, Germany and Austria

MATERIAL

42 LEW. 1W rats, 12 of which acted as controls

INTERVENTIONS

Gram negative sepsis was induced by intraperitoneal injection of 6 ml of a mixture of Escherichia coli (K1:H+) 10(10) organisms/ml, autogenous haemoglobin 2.9 ml (haemoglobin concentration 3%), 0.9% sodium chloride 3 ml, and suspension 0.1 ml. Control rats were given physiological saline 6 ml alone.

MAIN OUTCOME MEASURES

Concentrations of endotoxin, interferon gamma (IFN-gamma), and biopterin, and serum phospholipase A2 (PLA2) activity.

RESULTS

There were significant differences between the septic and control rats in concentrations of endotoxin (EU/ml) (median (interquartile range) 21.85 (2.02-159.5) compared with 0, p < 0.0001; IFN-gamma (pg/ml) 1263.0 (271.0-7575.0) compared with 101.0 (89.0-141.0), p < 0.0001; biopterin (nmol/L) 111.0 (66.4-156.3) compared with 53.7 (38.3-67.6), p < 0.001; and PLA2 (U/L) 163.0 (125.8-209.0) compared with 112.5 (88.5-126.5) p < 0.01.

CONCLUSIONS

Measurements of concentrations of endotoxin, IFN-gamma, pteridines, and PLA2 activity may well be adequate markers for early recognition of sepsis, and perhaps for grading it during the first 6 hours after induction. The allow a clear distinction to be made between septic and non-septic disorders in 87% of cases.

Disposition of 3H-labelled buserelin continuously infused into rats

The disposition of the gonadotropin-releasing hormone (GnRH) agonist buserelin was studied in male rats under conditions of long-term administration. Rats were continuously infused with about 30 pmole [3H]-buserelin/24 h subcutaneously by osmotic minipumps for 4-7 days. After killing the rats, the 3H-activity of the tissues was measured and was found to be highly concentrated (about 10-fold to plasma) only in the pituitary. The daily amounts of 3H-activity excreted in urine and faces were constant over the whole infusion period, suggesting steady state conditions. On a molar basis, of the infused dose of buserelin, 14.8% was found to be excreted into urine as intact peptide, and 16.5, 10.8 and 20.6% as the partial buserelin sequences 1-2, 1-3 and 5-9. It is concluded that the major elimination route of buserelin, constant with time, is glomerular filtration, followed by enzymatic degradation of part of the filtered peptide by kidney tubuli enzymes to the partial sequences 1-2, 1-3 and 5-9, which reflects the proteolytic breakdown of buserelin by kidney membrane peptidases in vitro. Based on the similarities in the pharmacokinetics, in vivo metabolities, and in vitro enzymatic degradabilities among the GnRH agonists that have the native GnRH sequence modified at position 6 with or without additional modification at the C-terminal, the elimination process as shown here for buserelin should also be valid for other GnRH agonists.

[Pancreatic duct occlusion with fibrin (glue) to protect the pancreatico-digestive anastomosis after resection of the head of the pancreas in oncologic surgery]

The PDO with FS represents a technically simple, quick and efficient method for the protection of pancreatic-jejunal anastomosis, which is endangered by dehiscences. We could prove--first, in an animal experimental, then in a clinical study of 93 patients--that neither subsequent dehiscence nor a pancreatic fistula occurred. Also, the loss of exo- and endocrine functions is low and can rather be considered as an expression of the extended resection of the pancreatic parenchyma in the scope of the oncological intervention.

[Field study with a vaccine against enzootic pneumonia of swine]

The EP vaccine Stellamune Myco was tested in 4 different trials. In a first trial, the daily weight increase and the incidence of lung lesions and their degree of severity were compared in non-vaccinated and vaccinated pigs originating from a herd infected with M. hyopneumoniae. The daily weight increases of the vaccinated animals were almost 60 g above that of the non-vaccinated and the number of altered lungs and the severity of the lung lesions was smaller in the vaccinated group. The effects were statistically different. In a second trial, no lesions were observed in 60% of the vaccinated animals. In the non-vaccinated group, the proportion was only about 35%. More severe lung lesions were only present in the non-vaccinated animals. In a third trial, it was observed that the animals originating from infected herds may excrete mycoplasmas despite the vaccination. In a fourth trial, it was determined that SPF piglets were not protected with the vaccination against an infection caused by M. hyopneumoniae.

[Surgical therapy of pancreatic carcinoma in elderly patients over 70]

Between October 1972 and December 1994, 519 pancreatic resections were performed at the Chirurgische Universitätsklinik Mannheim, 372 for pancreatic carcinoma. Of 328 patients who underwent a partial duodenopancreatectomy for cancer, 45 patients were older than 70 years: only in one case a partial duodenopancreatectomy was performed for chronic pancreatitis. In comparison to all patients the perioperative morbidity increased to 39.1% (21.5% vs. 39.1%). The perioperative mortality of all patients was 1.9%, the mortality of patients older than 70 years was 4.3%. The mean survival time of 28 patients who died subsequently was 30.6 (5-96) months. Despite increased perioperative morbidity and mortality, the patient's age is not considered to be a limiting factor to an attempt at curative resection of pancreatic or periampullary cancer.

Influence of alpha-helicity, amphipathicity and D-amino acid incorporation on the peptide-induced mast cell activation

Mast cell activation by polycationic substances is believed to result from a direct activation of G protein alpha subunits and it was suggested that the adaption of amphipathic, alpha-helical conformations would allow the peptide to reach the cytosolic compartment to interact with G proteins (Mousli et al., 194, Immunopharmacology 27, 1, for review). We investigated the histamine-releasing activity of model peptides as well as analogues of magainin 2 amide and neuropeptide Y with different amphipathicities and alpha-helix content on rat peritoneal mast cells. Amphipathic helicity is not a prerequisite for mast cell activation. Moreover, non-helical magainin peptides with high histamine-releasing activity were less active in the liberation of carboxyfluoresceine from negatively charged liposomes, indicating that peptide-induced mast cell activation and peptide-induced membrane perturbation do not correlate. In contrast to the negligible influence of the secondary structure, amino acid configuration may exert a striking influence on peptide-induced mast cell activation. Thus histamine-release by substance P was markedly impaired when the L-amino acids in the positively charged N-terminal region were replaced by D-amino acids, with [D-Arg1)substance P being the most inactive substance P diastreoisomer.

[The pharmacokinetics of the S35 labeled labeled garlic constituents alliin, allicin and vinyldithiine]

Three groups of 3 rats received oral doses (8 mg/kg) of garlic constituents (alliin, allicin and vinyldithiines (2-vinyl-[4H]-1,3-dithiine and 3-vinyl-[4H]-1,2-dithiine)) in the form of an oil macerate of the 35S-labeled substance. The measured activity was referred to 35S-alliin (35S-alliin equivalents). The blood activity levels in each group were monitored for 72 h. For 35S-allicin and the labeled vinyldithiines the excretion with the urine, feces, and exhaled air was also measured. The distribution among the organs (whole-body autoradiography) and the urinary metabolite pattern (thin-layer chromatography) were also determined. For 35S-alliin the blood activity profile differed considerably from those of 35S-allicin and the labeled vinyldithiines: both the absorption and the elimination of the radioactivity were distinctly faster than for the other garlic constituents, maximum blood levels being reached within the first 10 min and elimination from the blood being almost complete after 6 h. For the other garlic constituents the maximum blood levels were not reached until 30-60 min (35S-allicin) or 120 min (vinyldithiines) p.a. and blood levels > 1000 ng-Eq/ml were still present at the end of the study after 72 h. The mean total urinary and fecal excretion after 72 h was 85.5% (35S-allicin) or 92.3% (labeled vinyldithiines) of the dose. The urinary excretion indicates a minimum absorption rate of 65% (35S-allicin) or 73% (vinyldithiines). It is uncertain whether the 19-21% recovered in the feces was unabsorbed substance or had been excreted via the bile or intestinal mucosa. The exhaled air showed only traces of activity although the whole-body autoradiographs, after fairly long exposure (96 h), showed distinct enrichment of activity in the mucosa of the airways and pharynx. The activity is deposite mainly in the cartilage of the vertebral column and ribs. There was no detectable difference in organ distribution between 35S-allicin and the labeled vinyldithiines. All that could be established from the urinary metabolite pattern was that unchanged 35S-allicin and unchanged labeled vinyldithiines are absent. There is therefore extensive metabolization. The metabolites must have a very polar structure with acid functional groups since satisfactory separation was achievable only with acid solvent systems. Conjugates with sulfuric or glucuronic acid were not detectable. These results reveal no differences in pharmacokinetic behavior between 35S-allicin and the labeled vinyldithiines. A final verdict as to whether the metabolites, which may be pharmacologically active, are identical must await further studies designed to identify the metabolites.

The bkdR gene of Pseudomonas putida is required for expression of the bkd operon and encodes a protein related to Lrp of Escherichia coli

Branched-chain keto acid dehydrogenase is a multienzyme complex which is required for the metabolism of the branched-chain amino acids in Pseudomonas putida. The structural genes encoding all four proteins of the bkd operon have been cloned, and their nucleotide sequences have been determined (G. Burns, K. T. Madhusudhan, K. Hatter, and J. R. Sokatch, p. 177-184 in S. Silver, A. M. Chakrabarty, B. Iglewski, and S. Kaplan [ed.], Pseudomonas: Biotransformations, Pathogenesis, and Evolving Biotechnology, American Society for Microbiology, Washington D.C., 1990). An open reading frame which encoded a protein with 36.5% amino acid identity to the leucine-responsive regulatory protein (Lrp) of Escherichia coli was found immediately upstream of the bkd operon. Chromosomal mutations affecting this gene, named bkdR, resulted in a loss of ability to use branched-chain amino acids as carbon and energy sources and failure to produce branched-chain keto acid dehydrogenase. These mutations were complemented in trans by plasmids which contained intact bkdR. Mutations affecting bkdR did not have any effect on transport of branched-chain amino acids or transamination. Therefore, the bkdR gene product must affect expression of the bkd operon and regulation must be positive. Mutations affecting bkdR could also be complemented by plasmids containing lrp of E. coli. This is the first instance of a Lrp-like protein demonstrated to regulate expression of an operon outside of E. coli.

Cigarette smoking among women in Oklahoma: before, during, and after pregnancy

Data from the Oklahoma Pregnancy Risk Assessment Monitoring System (PRAMS) were assessed to determine the prevalence of maternal cigarette smoking and its relationship to pregnancy outcomes. A mail and telephone questionnaire was used to survey mothers between four and six months postpartum to obtain information about smoking and other maternal behaviors. Monthly samples were drawn from the state's live birth registry utilizing a systematic stratified sampling approach based on infant birth weight. A total of 3,051 responses were received between 1988 and 1990 for an overall return rate of 70%. Results of the study show approximately one-third (32%) of women in Oklahoma smoked 3 months prior to pregnancy, 22% smoked in their last 3 months of pregnancy, and 29% smoked shortly after delivery. Women who smoked during pregnancy were 2.2 times more likely to deliver a low birth weight (LBW) infant than nonsmokers, and 1.4 times more likely to have gained less than the recommended amount of weight. Additionally, women who smoked during pregnancy were 1.4 times more likely to begin prenatal care in the second or third trimester, or to receive no care at all. In conclusion, maternal smoking cessation has the potential for dramatically reducing preventable adverse outcomes of pregnancy.

[Endocrinously active parathyroid cysts. Their diagnosis by the determination of intact parathormone in the cyst fluid]

A 53-year-old woman with recurrent nephrolithiasis was found to have hypercalcaemia of 3.12 mmol/l and an intact parathormone level of 166 pg/ml, indicating primary hyperparathyroidism. Preoperative ultrasound examination to localize the parathyroid adenoma revealed a clear fluid-containing cyst in the right lobe of the thyroid. The aspirated fluid had an intact parathormone level of 306 pg/ml, twice that in serum. The cyst was removed surgically. 14 days postoperatively calcium and parathormone levels in serum had become normal without any calcium administration. Measuring the concentration of intact parathormone in the aspirated cyst fluid made possible not only the distinction from a thyroid cyst but also the precise preoperative localization of the parathyroid cyst.

Characterization of the mmsAB operon of Pseudomonas aeruginosa PAO encoding methylmalonate-semialdehyde dehydrogenase and 3-hydroxyisobutyrate dehydrogenase

A 5417-base pair (bp) region of Pseudomonas aeruginosa PAO chromosomal DNA containing the mmsAB operon and an upstream regulatory gene (mmsR) has been cloned and characterized. The operon contains two structural genes involved in valine metabolism: mmsA, which encodes methylmalonate-semialdehyde dehydrogenase; and mmsB, which encodes 3-hydroxyisobutyrate dehydrogenase. mmsA and mmsB share the same orientation and are separated by a 16-bp noncoding region. The transcriptional start site for the operon has been pinpointed to a cytidine residue located 77 bp from the translational start site of the operon. mmsR is located on the opposite strand and begins 134 bp from the translational start site of mmsA. MmsR has been identified as a member of the XylS/AraC family of transcriptional regulators and appears to act as a positive regulator of the mmsAB operon. Sequence comparison of MmsA to other proteins in the data bases revealed that MmsA belongs to the aldehyde dehydrogenase (NAD+) superfamily. MmsB shares a 44% amino acid identity with 3-hydroxyisobutyrate dehydrogenase from rat liver. Mutants with insertionally inactivated mmsR, mmsA, and mmsB grow slowly on valine/isoleucine medium and exhibit reduced enzyme activity in cell-free extracts compared to P. aeruginosa PAO.

[Pressure behavior in muscle compartments of the foot in defined stress, metatarsal and ankle joint fractures]

In addition to the importance of compartment syndrome in the lower leg, a growing interest is being shown in the muscle compartments of the foot region. The standard pressure rates in the muscle compartments of the foot comprise up to 4 kPa for men and up to 2.5 kPa for women. During graded exercise (n = 9) on the treadmill the pressure increased in line with the strain and declined again rapidly when the exercise stopped without showing any significant differences in pressure between the muscle compartments studied. In metatarsal and ankle joint fractures post-traumatic pressures were found which were as high as or higher than after 20 minutes on the treadmill and would make the development of a compartment syndrome possible. This points to the necessity of measuring the pressure in the muscle compartments of the patient's foot when there is a clinical suspicion of a compartment syndrome.

Role of octreotide in the prevention of postoperative complications following pancreatic resection

Though morbidity and mortality rates following pancreatic resection have improved in recent years, they are still around 35% and 5%, respectively. Typical complications, such as pancreatic fistula, abscess, and subsequent sepsis, are chiefly associated with exocrine pancreatic secretion. In order to clarify whether the perioperative inhibition of exocrine pancreatic secretion prevents complications, we assessed the efficacy of octreotide, a long-acting somatostatin analogue. We conducted a randomized, double-blind, placebo-controlled, multicenter trial in 246 patients undergoing major elective pancreatic surgery. Patients were stratified into a high-risk stratum (limited to patients with pancreatic and periampullary tumors) or low-risk stratum (patients with chronic pancreatitis). Patients received octreotide (3 x 100 micrograms) or placebo subcutaneously for 7 days perioperatively. Eleven complications were defined: death, leakage of anastomosis, pancreatic fistula, abscess, fluid collection, shock, sepsis, bleeding, pulmonary insufficiency, renal insufficiency, and postoperative pancreatitis. Two hundred patients underwent pancreatic head resection, 31 patients underwent left resection, and 15 patients had other procedures. The overall mortality rate within 90 days was 4.5%, with 3.2% in the octreotide group and 5.8% in the placebo group. The complication rate was 32% in the patients receiving octreotide (40 of 125 patients) and 55% in patients receiving placebo (67 of 121 patients) (p less than 0.005). In the patients in the high-risk stratum, complications were observed in 26 of the 68 (38%) patients treated with octreotide and in 46 of 71 (65%) patients given placebo (p less than 0.01). Whereas in patients in the low-risk stratum, the complication rate was 25% (14 of 57 patients) in those treated with octreotide and 42% (21 of 50 patients) in patients given placebo (p = NS). The perioperative application of octreotide reduces the occurrence of typical postoperative complications after pancreatic resection, particularly in patients with tumors.

Localization of occult persisting medullary thyroid carcinoma before microsurgical reoperation: high sensitivity of selective venous catheterization

In 14 patients with occult persisting medullary thyroid carcinoma, tumor tissue was removed by microsurgical reoperation in 13 of 14 patients. This resulted in biochemical improvement in all but 1 patient and biochemical cure in 3 patients (21%). The lateral compartment of the neck or the upper mediastinum was involved in all but 1 patient. Before microsurgical reoperation, selective venous catheterization (SVC) for serum sampling along with serum calcitonin (CT) determination was done and compared to other localization methods. Tumor tissue could be localized correctly by SVC in 89% (CT gradient 1.21-2.02), computed tomography in 38%, and ultrasound in 28%. In patients with an elevated CT level after initial surgery and clinically occult disease, SVC is recommended for localization of tumor tissue. The affected side of the neck should be reoperated on with microdissection of the central and lateral compartment of the neck and the upper mediastinum. With this procedure, the cure rate of reoperation in patients with persistent occult MTC can be improved.

Obstetrical practice survey report. Healthy Futures Program, May 2, 1991

Oklahoma physicians in three specialty areas (ob/gyn, family practice, and general practice) were surveyed in regard to their practice of obstetrics. The 611 physicians who responded included a representative sample in regard to county of practice, rural vs urban, age, degree (DO & MD), specialty, and type of practice. Respondents accounted for 51% of the total 1989 births in Oklahoma during calendar year 1989. The vast majority (greater than 90%) of respondents report that they normally provide delivery services and prenatal care in combination. Cesarean sections are performed by almost all ob/gyns (97.6%), more than half of the family practitioners (56.5%), and a very few general practitioners (18.9%). Half of all physicians responding have made changes in their obstetric practice in the last 3 years. The most common changes are: reducing care of medically high risk, uninsured, and/or Medicaid patients. The most important reasons for these changes are: fear of obstetric malpractice suits, inconvenience of obstetrics and excessive professional liability insurance premiums. Specific reasons for reducing care to medically high risk patients were reported to be: increased medical legal liability, belief that high risk patients should be cared for by specialists, and lack of Medicaid reimbursement for diagnostic services. Almost 90% of the physicians responding to the survey are required to carry a minimum amount of professional liability insurance by the hospital where they practice with the most frequently stated amount being $1,000,000. Current average "global fees" reported by the respondents were $1,202 for a spontaneous vaginal delivery and $1,543 for a cesarean delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

In-vivo release of a GnRH agonist from a slow-release poly(lactide-glycolide) copolymer preparation: comparison in rat, rabbit and guinea-pig

Different batches of 50:50 poly((+-)-lactide-glycolide) copolymer (PLG) were used as biodegradable carriers for D-Phe6-gonadotropin-releasing hormone (GnRHa) in the form of injectable long-acting implants loaded with 10% GnRHa and tracer amounts of [125I]GnRHa. After their injection subcutaneously into rats, rabbits, and guinea-pigs, the release kinetics of the peptide were determined by counting the radioactivity remaining in the implants (i) after recovery from the rats after death or (ii) directly on the skin above the injection site of rabbits and guinea-pigs in-vivo. No significant differences in the release pattern of the peptide amongst the three species whether the release process was controlled by diffusion or by degradation of the polymeric matrix were found. It is concluded that the results of in-vivo release tests using laboratory animals are valid for man and that enzymes are not involved in the degradation of the polymeric matrix. The results may be of general importance for the use of long-term release PLG formulations of highly active drugs, especially peptides and proteins.

[Exocrine function of a heterotopically transplanted pancreas segment in humans]

Pancreatic secretion is involved in circadian regulation of the whole organism. This observation was obtained in animals and humans with pancreatic fistulas. We report on three patients in whom the pancreas was removed totally or subtotally because of chronic pancreatitis with severe pain. A segment of the removed gland was transplanted into the thigh in order to preserve endocrine function. The pancreatic duct was drained by a polyethylene tube until pancreatic duct occlusion. Postoperatively juice volume increased within 3 days and remained constant afterwards with 300 ml in 24 hours. Secretin, cholecystokinin and food intake are able to stimulate the transplanted segment in a typical manner. The secretion showed circadian changes. In all patients the pancreatic juice content of protein, amylase, trypsinogen, calcium, and zink decreased till 11 p.m. After 11 p.m. the content of all substances increased and reached maximal values at 6 a.m. Flow rates and therefore output per minute decreased greatly till 6 a.m. The large juice volume of 300 ml in 24 hours is perhaps the consequence of a break down of the feedback mechanism between intraduodenal trypsin activity and CCK-release. The changes during the night may be of pathogenetic relevance. In the early morning pancreatic juice is highly concentrated and the flow rate is very low. High protein concentrations, high calcium concentrations, and reduced flow rates may lead to protein and calcium carbonate precipitates. This mechanism is under discussion in the pathogenesis of chronic pancreatitis.