Non-invasive transgenic mouse genotyping using stool analysis

Commonly applied genotyping of transgenic mice involves using tail or ear biopsies which may cause discomfort to the animal. We tested the possibility of polymerase chain reaction (PCR)-based mouse genotyping using stool specimens from three transgenic mouse lines that overexpress 10-18 transgene copies of human keratin polypeptide 18, as compared to genotyping using tail biopsies. Stool specimens were obtained with ease and provided easy detection of the human transgene product. The method was also able to detect endogenous mouse actin and keratin genes which presumably are present at two copies each. Nested PCR was not necessary for genotyping using stool-derived genomic material but did increase the relative magnitude of the signal obtained. The non-invasive genotyping method described herein offers a reproducible, sensitive and effective modality that could replace invasive tissue sampling procedures currently used to test thousands of genetically altered mice.

[Effects of anesthesia with inhalation anesthetics on excitation, conduction and refractory parameters of the heart. Experiments in dogs]

Cardiac excitation, conduction, and refractory parameters of the heart were investigated in 40 beagle dogs to obtain basic values under the influence of the following 9 inhalation anaesthetic regimes using HIS-bundle electrography and programmed stimulation: 1. halothane; 2. enflurane; 3. isoflurane; 4. halothane+nitrous oxide; 4. enflurane+nitrous oxide; 6. isoflurane+nitrous oxide; 7. alfentanil/midazolam/succinylcholine+nitrous oxide; 8. fentanyl/midazolam/pancuronium bromide+nitrous oxide; 9. propofol+nitrous oxide. It could be shown that inhalation anaesthetics under laboratory conditions exert some influences on the observed cardiac parameters, although they are not as strong as those of intravenous anaesthetics. Therefore their effects should be considered in experiments with other substances or in cardiovascular results.

The pharmacist's role in the optimal delivery of primary care in a managed care world

For managed care to continue positive growth, pharmacists will have to offer support measures for primary care physicians, even as efforts are made to increase the supply of these physicians. The pharmacy practice at Medical University of South Carolina Family Medicine Center has gained national recognition for providing an expansive role model for pharmacists who are committed to providing pharmaceutical care and related services in primary care surroundings. This article discusses managed care in the primary care arena and pharmacists' role in providing pharmaceutical care and teaching future pharmacists their role in a managed primary care world.

[Basic values of blood coagulation parameters in pigs (Sus scrofa domesticus)]

On 23 clinical healthy pigs (2-4 months of age, body weight 13-42 kg) under ketamin-pentobarbital anaesthesia blood plasma coagulation parameters have been investigated. To obtain basic values 26 parameters were measured: number of thrombocytes, parameters of thrombelastogram and resonance-thrombogram, prothrombin time, activated partial thromboplastin time, thrombin time, reptilase time, factors I, II, V, VII, VIII, X, antithrombin III, plasminogen, alpha 1-antitrypsin, alpha 2-antiplasmin, alpha 2-macroglobulin, fibrin degradation products D and E and euglobulin lysis-time. Parameters calculated in percent should be measured against a pig plasma pool. Measurement against a human plasma pool are hardly valid in values higher than 100%. In comparison to man the results indicate modifications of fibrinogenesis and fibrinolysis in pigs.

[Effects of intravenous anaesthetics on excitation, conduction, and refractory parameters of the heart. Experimental study in the dog]

Cardiac excitation, conduction, and refractory parameters of the heart were investigated in 59 beagle dogs to obtain basic values under the influence of the following 11 intravenous anaesthetic regimes using HIS-bundle electrography and programmed stimulation: 1. Alfentanil/midazolam/succinylcholine; 2. alfentanil/midazolam/succinylcholine/atropine; 3. fentanyl/midazolam/pancuronium bromide; 4. fentanyl-droperidol/chloralose/urethane; 5. ketamine/xylazine; 6. ketamine/xylazine/atropine; 7. propionylpromazine/pentobarbital; 8. propionylpromazine/levomethadon; 9. propofol; 10. propofol/alfentanil; 11. Tiletamine-zolazepam. It could be shown, that some intravenous anaesthetics under laboratory conditions have a strong influence on the observed cardiac parameters that must be considered in experiments with other substances or in cardiovascular results.

[The cardiotoxicity of bupivacaine during pacemaker stimulation is dependent on the stimulation frequency. Results of an experimental study]

The cardiotoxic effects of bupivacaine are related to the temporal dispersion of effective refractory periods in different parts of the cardiac conduction system. This effect facilitates the occurrence of re-entry arrhythmias under burst stimulation [4, 8]. In this study physiological increments in heart rate were simulated by cardiac pacing, and the electrophysiological and haemodynamic effects under the influence of cardiotoxic concentrations of bupivacaine were measured. METHODS. After institutional approval we generated cardiotoxic arterial plasma concentrations of bupivacaine (6.9 +/- 1.6 micrograms/ml) in pigs (n = 8; 15-22 kg) by i.v. injection of 4 mg bupivacaine/kg, followed by a constant rate infusion of 0.2 mg/kg per min [8]. The pigs were anaesthetized with midazolam, fentanyl and pancuronium and normoventilated with a FiO2 of 0.4. Internal right atrial and right ventricular pacing was performed with increasing frequencies of 20, 40, 60, 80 and 100 stimulations/min above individual spontaneous heart rates (AL) before (control) and after the administration of bupivacaine. ECG, MAP, LVSP, dp/dtmax and stimulation thresholds were recorded. Student's t-test, and the U-test of Wilcoxon, Mann and Whitney were used for statistical testing with a significance level of 0.05. RESULTS. By inducing a frequency-dependent increase in stimulation threshold, bupivacaine prevented regular atrial pacing with frequencies higher than AL + 60. Ventricular pacing with a frequency of AL+40 induced a lethal arrhythmia in 1 animal. In the remaining 7 pigs ventricular pacing showed a frequency-dependent increase in stimulation thresholds (Fig. 1) and stimulus-QRS intervals (Fig. 5). MAP (Fig. 2), LVSP (Fig. 3) and cardiac inotropy (Fig. 4) showed frequency-dependent decreases under ventricular pacing. CONCLUSIONS. The toxic effects of bupivacaine on pacing thresholds, av conduction, intraventricular conduction, cardiac inotropy, and blood pressure are modulated by the stimulation frequency of a cardiac pacemaker. The cardiotoxic effects of bupivacaine seem to be use dependent. Even minor increments in heart rate can induce malignant arrhythmias. Cardiac pacing can be difficult in the presence of toxic bupivacaine concentrations, and high-frequency pacing should be avoided. It has to be verified whether higher heart rates generated by the physiological pacemakers of the heart do also increase the cardio-circulatory toxicity of bupivacaine. If that holds true, drugs that can induce tachycardias should be avoided in the treatment of bupivacaine toxicity.

[Acquired disorders of peritoneal cavity muscles. Abdominal wall denervation in pregnancy, denervation incontinence, and continent and incontinent constipation]

The peritoneal cavity has a fascial skeleton that is kept under tension by permanent variable resting tone maintained by the abdominal muscles. The lateral abdominal muscles, the diaphragm and the pelvic floor are all components of this fasciomuscular support system. Voluntary and reflective changes in muscle tension allow the entry and exit of matter into and out of the spherical abdominal cavity by opening and closing of specialized wall segments called sphincters. We have previously demonstrated the existence of a resting tone in the tail muscles of mammals from which the human pelvic floor muscles are derived. The pelvic floor and its integrated sphincters form the anorectal organ of continence. This organ is much weaker in females than in males. The spinal centers that govern continence, contain in the female significantly fewer ganglion cells than the corresponding centers in the male. Childbirth and a commonly found tendency to develop constipation are additional stressors for the congenitally weaker female organ of continence. We explain in this paper why the abdominal wall and the pelvic floor may suffer stretch-induced denervation injuries during pregnancy and delivery. Such damage may persist in later life and can give rise to incontinence and "flabby abdomen". Based on our work in this field, we found a new differentiation between continent and incontinent constipation. Continent constipation is caused by spasticity of the pelvic floor characterized by abnormally high sphincter activity. This spastic pelvic floor syndrome can be treated successfully by psychotherapeutic techniques. Incontinent constipation, in contrast, is always associated with subnormal activity of the sphincters and may be a cause of rectal prolapse. It can be treated successfully by anterior rectosigmoid resection. Incontinent constipation will also require operative approximation of the levators in many cases. Improvement cannot be expected to result from this procedure, however, unless the pelvic floor shows some residual resting activity.

Regional metabolic rate of exogenous glucose in the isoprenaline and dobutamine stimulated canine myocardium as estimated by the 2-deoxy-D[1-14C]glucose method

The effect of beta-adrenoceptor stimulation by isoprenaline and dobutamine on the transmural distribution pattern of regional myocardial metabolic rate of exogenous glucose (RMMRGlc) was studied in the anesthetized closed chest dog using the 2-deoxy-D[1-14C]glucose method. In a previous series a lumped constant (LC) value of 0.93 +/- 0.47 (1 SD) was measured for [14C]2-deoxyglucose in the canine myocardium. In the control group (N = 12) RMMRGlc was significantly higher in the subendocardial layer of the left ventricular free wall than in both the middle and subepicardial layer, where it was quite evenly distributed (P less than or equal to 0.05). With i.v. dobutamine (N = 8) RMMRGlc was significantly lower in the midportion of left ventricular free wall than in the subepicardial layer (P less than or equal to 0.05), but it was not different from the inner wall section. Significant differences between the subepicardial and subendocardial portions of the left ventricular free wall could not be found, either. In the isoprenaline group (N = 9) no transmural gradients of RMMRGlc were observed in the left ventricular myocardium. In all groups, both the interventricular septum and the right ventricular free wall exhibited homogeneous distribution patterns of RMMRGlc. It is concluded that transmural distribution patterns of exogenous glucose utilization probably reflect corresponding gradients in energy demands of the left ventricular wall. Redistribution of RMMRGlc in the isoprenaline and dobutamine groups may result from altered working conditions, a change in local inotropic state of the left ventricular myocardium, or from regional differences in the proportions of substrate utilization, and from regional differences in adrenoceptor density.

Contribution of the gastrointestinal tract to lorazepam conjugation and clonazepam nitroreduction

Domestic pigs received single intravenous and oral doses of lorazepam or clonazepam (1 mg/kg), benzodiazepine derivatives biotransformed by glucuronide conjugation and nitroreduction, respectively. Blood samples were simultaneously drawn from portal venous and systemic venous sampling sites during 8 h after dosage. After intravenous dosage with either drug, the area under the serum concentration curve (AUC) for the intact drug, as well as for the principal metabolites (lorazepam glucuronide and 7-aminoclonazepam, respectively), was nearly identical between portal and systemic serum. After oral dosage, absolute systemic availability (relative to intravenous administration) of both lorazepam and clonazepam was incomplete (mean values: 29 and 49%, respectively); however, metabolite levels were also correspondingly lower between oral and intravenous dosages. First-pass hepatic extraction also occurred for both drugs, with mean systemic/portal AUC ratios of 0.60 for lorazepam and 0.74 for clonazepam. Pretreatment with neomycin (1.0 g) had a minimal effect on portal or systemic AUC for intact clonazepam after oral dosage, but 7-aminoclonazepam concentrations were reduced by neomycin pretreatment. Thus incomplete absorption, together with first-pass hepatic biotransformation, appears to explain the incomplete systemic availability of orally administered lorazepam or clonazepam. Biotransformation within the gastrointestinal tract or during absorption through the gastrointestinal mucosa contributes minimally.

The effects of microsphere injections into the left atrium on the myocardial blood supply measured by thermal conductance probes

Former experiments with thermal conduction probes showed signs of reductions or increases of myocardial perfusion shortly after injection of microspheres into the left atrium. Because of this, 210 measurements made during experiments on 66 dogs under propionyl-promazine/pentobarbital narcosis were newly analysed to verify a possible influence of microspheres (9 microns phi) injected into the left atrium on microcirculation. Using 20 additional dogs in identically performed experiments, the myocardial perfusion was measured using thermal conductance probes, following injections of isotonic NaCl solution (8 ml each), Ringer's solution, 5% glucose, the subject's blood, and isotonic NaCl solution mixed with the surface-active substance Tween 80. These suspension media were injected both with and without unlabelled microspheres (8.6 microns phi). The results led to the following conclusions: An obligatory decrease in the blood supply as the result of a mechanical blocking of capillaries by microspheres can be ruled out. The particles, the suspension media, and a suspension temperature not sufficiently adjusted to the body temperature induce reactive negative or positive changes in the microcirculation of the myocardium. This was found in approx. 45%-75% of cases. Solutions containing particles cause, in the majority of cases, a decrease. The suspension medium with the smallest effect proved to be isotonic NaCl solution. From the results one can conclude that artefacts may arise from the application of the heat conductance probe method when the temperatures are not perfectly matched. However, the injected solution itself can often lead to various reactions in microcirculation which may last up to 5 min. (ABSTRACT TRUNCATED AT 250 WORDS)

The influence of molsidomine on myocardial ischemia and ventricular dynamics. An in-vivo study in anesthetized dogs by means of computer tomography

In six anesthetized dogs with myocardium partially damaged by ischemia (LAD occlusion), the effect of an i.v. bolus injection of 0.05 mg molsidomine/kg body weight followed by a 6-h i.v. infusion of 0.5 micrograms molsidomine/kg/min on the volume of myocardial ischemia, the relative remaining blood flow in the ischemic area, and the dynamics of the left ventricle were examined by means of computer tomography. The extent of the ischemic volume in the group treated with molsidomine was by far lower than in the control group; this difference was significant if one takes into account the individual heart size. The relative remaining blood flow in the ischemic region was not influenced by molsidomine. The reduction of preload and afterload resulted in corresponding changes in left ventricular areas, segments of these areas, the long axis, thickness of myocardium, ejection fraction and stroke volume. Aortic pressure was lowered insignificantly, heart rate remained nearly unchanged. Plasma analyses of molsidomine. SIN 1 and SIN 1C show that the applied dosage was sufficient to reach a constant concentration over the whole period of observation in the dog.

Pharmacokinetics and CSF entry of flurazepam in dogs

Anesthetized dogs received a single 1.0-mg/kg intravenous dose of flurazepam hydrochloride, following which multiple blood and cerebrospinal fluid (CSF) samples were taken over the next 8 h. Concentrations of flurazepam and its metabolite, desalkylflurazepam, were determined by gas chromatography with electron-capture detection. Mean kinetic variables for flurazepam were: volume of distribution 7.9 l/kg, elimination half-life 2.3 h, clearance 37 ml/min/kg, serum free fraction 25% unbound. The metabolic product desalkylflurazepam appeared in serum in low concentrations, and was eliminated with a half-life of 4.9 h. Flurazepam rapidly entered CSF, then was eliminated in parallel with flurazepam in serum. However, the extent of entry into CSF was limited, with the mean ratio of area under the curve for CSF versus serum (0.24) nearly identical to the serum free fraction. Thus, intravenous flurazepam in dogs is characterized by extensive distribution, high clearance, and short half-life. Entry into CSF is rapid, and appears governed by passive diffusion. The extent of CSF entry is limited by protein binding in serum.

Hepatic vs. gastrointestinal presystemic extraction of oral midazolam and flurazepam

An experimental model was developed to elucidate the site of presystemic extraction of drugs with incomplete bioavailability due to high extraction after p.o. dosage. Domestic pigs received single i.v. or p.o. doses of midazolam (1 mg/kg) or flurazepam (2 mg/kg), two benzodiazepine derivatives with high presystemic extraction after p.o. dosage. Multiple blood samples were simultaneously drawn from the portal vein and from a systemic vein during 8 hr after dosage. After i.v. administration, both drugs had high systemic serum clearance, averaging 24 ml/min/kg. Area under the serum concentration curve (AUC) for systemic vs. portal sites was nearly identical for midazolam (769 vs. 737 ng/ml x hr); for flurazepam, systemic AUC exceeded portal AUC (1035 vs. 778 ng/ml x hr, P less than .01). After p.o. dosage, the systemic/portal AUC ratio averaged 0.15 for midazolam and 0.11 for flurazepam; for both drugs, portal AUC after p.o. dosage did not differ significantly from systemic AUC after i.v. administration. Thus, the extensive presystemic extraction of orally administered midazolam and flurazepam are mainly attributable to hepatic biotransformation rather than metabolism either within the gastrointestinal tract or during absorption into the portal circulation.

Endobronchial instillation of epinephrine during cardiopulmonary resuscitation

We used a standard animal CPR model to study the effectiveness and hemodynamic response of 100 micrograms/kg epinephrine administered endobronchially and to compare the findings after conventional iv administration. Results showed that the endobronchial and iv epinephrine medication improved the survival rate by 100% compared to that of a control group receiving no medication. Although the hemodynamic conditions during cardiac compression were not significantly different after both routes of drug administration, endobronchial instillation produced a prolonged drug action during the first hour of restored spontaneous circulation. A more extensive use of this type of drug administration, especially in out-of-hospital resuscitation, is suggested.

[Effect of forced respiration on the stress on puncture channels of sutures in transverse laparotomies of the upper abdomen; experimental studies in the anesthesized dog]

In 11 mongrel dogs in propiophenylpromazine-pentobarbital-anaesthesia the influence of forced respiration on the load of puncture channels of a suture was investigated. For this horizontal suture in the upper abdominal wall, threads No. 3 USP and round needles No. ECT-4 were used. The experiments were carried out in supine position with stretched hindlegs, in supine position with relaxed hindlegs, in lateral position, and in hanging abdominal position. Measurements were performed with a selfconstructed resistance strain gauge element. Rising forced respiration pressure increased the inspiratory load of puncture channels, but there were no significant differences between spontaneous breathing and forced respiration with pressure of 10 cm H2O. In contrary to this there were highly significant differences between spontaneous breathing and forced respiration with pressure of 20 and 30 cm H2O (multiple variance analysis). For instance the load during forced respiration with a pressure of 30 cm H2O in supine position with relaxed hindlegs rose about 67% above pressure values of spontaneous breathing. It could be shown that the expiratory load in the puncture channels was not influenced by forced respiration pressure, but depended on the body position; in dogs it was minimal in side position (45-48 g), higher in supine position with relaxed hindlegs (67-71 g), even higher in supine position with stretched hindlegs (88-92 g), and maximal in hanging abdominal position (109-113 g). By this investigation the increase of load in the puncture channels during forced respiration with pressures of 20 and 30 cm H2O was quantified.

[Endobronchial administration of adrenaline in cardiopulmonary resuscitation: pharmacokinetic and dynamic studies in the dog]

The present animal study was designed to investigate the pharmacokinetic behavior of epinephrine after endobronchial (e.b.) and intravenous (i.v.) administration and its correlation to pharmacodynamic measurements. We found the effectiveness of e.b.-epinephrine (100 micrograms/kg BW) to be in the same magnitude as i.v.-epinephrine (100 micrograms/kg BW) with only a slight delay in the pharmacodynamic onset of a few seconds. The bioavailability of e.b.-administration of epinephrine was in the range of 80-85%. The therapeutic effect of e.b.-epinephrine (100 micrograms/kg BW) lasted much longer (30 min) when compared to i.v.-epinephrine (10 micrograms/kg BW) where the pharmacodynamic effect was terminated after 3 to 5 min. For the clinical situation of cardiopulmonary resuscitation a dose of 2-3 mg epinephrine in 5-10 ml of physiological saline instilled deeply into the bronchial system should be considered as alternative administration technique with fast onset and good effectiveness.

[Measurement of absolute intravascular flow velocity using digital subtraction angiography]

Experiments on phantoms showed very good correlation between flow velocity, as calculated from time-density curves, and theoretical values. After further development using an inter-active computer programme, DSA measurements of flow velocity are now undergoing further experimental investigation, but are also available for routine clinical examination.

[Computed tomography of the heart. Technic for quantitative evaluation of the perfusion of the ischemic myocardial region. Experimental basis]

A CT standard procedure has been developed in six series of experiments, using 62 anaesthetised dogs in order to quantitative relative blood flow through ischaemic heart muscle. Measurements of cardiac dynamics by means of contrast media were less strictly controlled. The use of the standardised procedures with contrast injections is necessary because of the variable perfusion and washout intervals of the contrast in normal and ischaemic myocardium.

Cerebrospinal fluid uptake and peripheral distribution of centrally acting drugs: relation to lipid solubility

In an anaesthetized dog model, serum kinetics and CSF entry were determined after i.v. administration of the following 8 drugs: salicylic acid (as acetylsalicylic acid), antipyrine, acetaminophen (paracetamol), lidocaine (lignocaine), trimipramine, amitriptyline, haloperidol, and imipramine. Kinetic variables were evaluated in relation to in-vitro lipophilicity, measured by the reverse-phase high-pressure liquid chromatographic (HPLC) retention index. After correction for individual values of serum binding (determined as the CSF: serum ratio at equilibrium), in-vivo volume of distribution was highly correlated with HPLC retention (r = 0.92). Conversely, the time of peak CSF concentration and the CSF entry half-life were negatively correlated with HPLC retention (r = -0.83 and -0.63, respectively). Thus lipophilicity is a physiochemical property which has an influence on the peripheral distribution of drugs as well as their rate of entry into CSF.

Relation of myocardial blood flow and initial cardiac uptake of 15-(p-123I-phenyl)-pentadecanoic acid in the canine heart

In 8 pentobarbital-anesthetized mongrel dogs the correlation between regional myocardial blood flow (RMBF) and regional cardiac uptake of 15-(p-123I-phenyl)-pentadecanoic acid (IPPA) was determined. Three animals were studied under control conditions, in three dogs an acute ischemia was produced by LAD ligation, and two dogs were paced at 195 beats/min. RMBF values were 20-50 ml/min X 100 g in acutely ischemic myocardium. 90-120 ml/min X 100 g under normal conditions and 200-250 ml/min X 100 g during pacing-induced stimulation. Total cardiac uptake of IPPA was 4.5-6% of the injected dose. In normal and acutely ischemic myocardium a good correlation between RMBF and IPPA uptake was obtained. Under stimulated conditions only a moderate increase of IPPA accumulation was found. At RMBF values above 150-170 ml/min X 100 g an upper limit of IPPA uptake was observed and can be explained by limited diffusion or an increased utilization of alternative substrates.

[Electrical and motor activity of the rectum following low anastomosis]

Electrical and motor activity of smooth muscle of the canine rectum was registered by transanal recording following low rectum anastomosis. The relaxation reflex of the anal canal had disappeared distal of the anastomosis in the first postoperative week, and electrical slow waves and pressure waves were desynchronized proximal and distal of the anastomosis. The resting pressure of the rectal wall had increased above preoperative values. After wound healing had accomplished the relaxation reflex and the synchronization of electrical and mechanical activity proximal and distal of the anastomosis did occur again. It is concluded that the rectal wall provides the pathways for the relaxation reflex of the anal canal. After wound healing has finished these pathways are restored across the anastomosis.

[Relations between ventricle function, myocardial oxygen consumption and coronary circulation following sublingual administration of nitroglycerin]

The relationships between ventricular function, coronary blood flow, and myocardial oxygen consumption after sublingual administration of 1.6 mg nitroglycerin (TNG) were investigated in 12 patients. Left ventricular volumes, determined from cineventriculograms (enddiastolic volume index and endsystolic volume index), decreased (p less than 0.005) after TNG, as did left ventricular peak pressure (p less than 0.01), left ventricular enddiastolic pressure (p less than 0.005), mean aortic pressure (p less than 0.005), and mean pulmonary artery pressure (p less than 0.001). Due to the decrease in enddiastolic volume and the insignificant change in stroke volume, ejection fraction increased (p less than 0.05). Heart rate did not change significantly. In spite of an increase in the vessel diameter (13%, p less than 0.005), systolic and diastolic coronary blood flow, measured by means of a photodensitometric technique, decreased insignificantly by an average of approx. 15%. Similarly the change in myocardial oxygen consumption, calculated according to Bretschneider, decreased insignificantly by an average of approx. 10%. The correlation of changes in coronary blood flow and myocardial oxygen consumption was evaluated statistically by the use of the 2 X 2 contingency table in conjunction with the chi 2 McNamar test: patients with a decrease in myocardial oxygen consumption also showed a decrease in coronary blood flow (p less than 0.05). This implies that coronary blood flow is determined by myocardial oxygen consumption, which is altered by the systemic effects of TNG.