Quantitative whole-body autoradiographic analysis of the tissue distribution of orally-administered [14C]cholesterol in hypercholesterolemic rats

The cholesterol-fed rat model has been used to examine the distribution of radiolabeled cholesterol by whole-body autoradiographic and quantitative videodensitometric methods. Animals were fed a hypercholesterolemic diet for 7 days, and were subsequently killed at 3, 6, 12, 24, or 72 h following a single oral dose of [14C]cholesterol. Maximum blood and tissue levels were observed at 12 h, while liver and adrenals were the most intensely labeled tissues. Liver maintained consistently high levels over the course of the study, while activity in other tissues declined moderately by 72 h, indicating the long half-life of cholesterol radioequivalents in tissue. The results of these experiments suggest that autoradiographic examination of cholesterol distribution in animals treated with pharmaceutical agents designed to modify cholesterol absorption or clearance will be useful in providing supplemental or confirmatory information on the drugs' mode of action.

Direct puncture of the cavernous sinus for obliteration of a recurrent carotid-cavernous fistula

The authors report direct transcutaneous puncture of the cavernous sinus through an intact orbit for embolization of a recurrent carotid-cavernous fistula (CCF) after 10 prior operations. The fistula was obliterated completely with this technique. No significant complication was noted except temporary ptosis for about 2 months. When other approaches are difficult or impossible, this technique can be an alternate way to treat a recurrent CCF after a trapping procedure.

Metabolic labeling of human thyroglobulin with [35S]sulfate: incorporation into chondroitin 6-sulfate and endoglycosidase-F-susceptible carbohydrate units

To study the incorporation of sulfate into thyroglobulin, human thyroid tissue was incubated with [35S]sulfate. Labeled thyroglobulin was purified by ammonium sulfate precipitation, gel exclusion chromatography, and equilibrium density gradient centrifugation, the last of these specifically to remove proteoglycans. [35S]Sulfate was found in thyroglobulin with low density, indicating that sulfate was incorporated into newly synthesized molecules before their iodination. Chondroitin ABC lyase and chondroitin AC lyase released equal amounts of [35S]sulfate, demonstrating the presence of chondroitin units, and TLC showed this to be predominantly chondroitin 6-sulfate. Additional [35S]sulfate was released by endoglycosidase-F (Endo-F), but not by Endo-H. The Endo-F-sensitive sulfate-labeled complex carbohydrate units were heterogeneous, one fraction passing through a Concanavalin-A-Sepharose column without delay and another fraction showing weak affinity for the lectin. More than 90% of the incorporated [35S]sulfate was accounted for by the chondroitin ABC lyase and Endo-F-sensitive fractions. Thus, human thyroglobulin contains sulfate in at least three types of carbohydrate units, 1) chondroitin 6-sulfate units, 2) complex units with no affinity for Concanavalin-A (tri- or tetraantennary forms), and 3) complex units with weak affinity for Concanavalin-A (biantennary forms).

Continuous electromyography for monitoring depth of anesthesia

Utilizing a randomized, controlled study design, the clinical utility of monitoring spontaneous electromyography during methohexital anesthesia was evaluated for short outpatient gynecologic procedures. In the experimental group (n = 20), the anesthesiologist used conventional monitors as well as the Datex ABM device for determining the maintenance anesthetic requirement. The control group (n = 20) was monitored in an identical fashion, but the video monitor screen was turned off during the operation. The methohexital maintenance requirement was nonsignificantly decreased (5.0 +/- 1.2 vs 5.6 +/- 1.8 mg/min) in the experimental group. Adequacy of anesthesia (as determined by cardiorespiratory stability and the absence of purposeful movement during the maintenance period) did not differ between the two study groups. Although the awakening time for the experimental group (2.9 +/- 1.9 minutes) was decreased to a statistically significant degree compared to the control group (4.5 +/- 3.0 minutes), the difference was of no clinical significance. Thus, continuous electromyographic and EEG monitoring with the Datex ABM device did not significantly improve administration of methohexital during brief outpatient procedures.

Pharmacokinetics of intravenous and oral enoxacin in healthy volunteers

In a randomized, crossover study single 200 and 800 mg doses of enoxacin were administered intravenously and orally to eight healthy normal volunteers. Plasma and urinary enoxacin concentrations and urinary concentrations of its oxo-metabolite were determined by high-performance liquid chromatography. At the end of a 1 h intravenous infusion period, mean enoxacin plasma concentrations were 1.8 and 6.6 mg/l for the 200 and 800 mg doses, respectively. Disappearance of enoxacin from the systemic circulation appeared to follow first order kinetics with harmonic mean elimination half lives of 3.3 and 4.7 h for the 200 and 800 mg dose groups, respectively. However, enoxacin kinetics were dose-dependent over the dose range tested. Total body clearance decreased and elimination half-life increased with increasing dose. The volume of distribution was large (2.8 l/kg) and independent of dose. Absorption of orally administered enoxacin was rapid, with mean peak plasma concentrations (1.0 and 3.8 mg/l) appearing one to two hours postdose. Absolute oral bioavailability averaged 89%, and was independent of the dose administered. Cumulative enoxacin urinary recovery accounted for 51-53% of the dose irrespective of dose or route of administration. Enoxacin renal clearance exceeded creatinine clearance indicating that urinary excretion of enoxacin involved both glomerular filtration and tubular secretion. Urinary excretion of the oxo-metabolite averaged 16% and 11% following the 200 and 800 mg dose, respectively. Evidence of dose dependent decrease in enoxacin renal clearance and formation of its oxo-metabolite was observed. Enoxacin was well tolerated during the course of the trial. The present study shows that enoxacin pharmacokinetics can be characterized by apparent first order elimination, large volume of distribution, and dose-dependent increase of half life. Oral absorption of enoxacin is complete over a wide dose range.

Hepatic cytochrome P-450j induction in the spontaneously diabetic BB rat

Hepatic microsomal cytochrome P-450j has been studied using the male spontaneously diabetic BB rat as a model for insulin-dependent diabetes. This approach avoids any direct hepatotoxic effects from chemical diabetogenic agents. Both diabetic rats maintained on insulin and nondiabetic littermates were used as controls. Levels of cytochrome P-450j were increased approximately 3-fold in the diabetics 4 days after the cessation of insulin therapy. In addition, cytochrome P-450j-catalyzed enzymatic activities, aniline hydroxylation, and N-nitrosodimethylamine N-demethylation were increased by the diabetic state at this same time period. Cytochrome P-450f remained at control levels in all groups of animals. In order to test the hypothesis that ketone bodies are involved in the increase in cytochrome P-450j in the diabetic state, plasma beta-hydroxybutyrate levels were monitored. Hepatic aniline hydroxylation, N-nitrosodimethylamine N-demethylation, and cytochrome P-450j levels in individual animals were found to correlate with plasma beta-hydroxybutyrate levels (r = 0.59-0.71 p less than 0.001). In contrast, no significant correlation between levels of cytochrome P-450j and plasma glucose, insulin, or cholesterol was observed in individual animals (r = 0.07-0.23, p greater than 0.4). We conclude that cytochrome P-450j is induced in the livers of spontaneously diabetic rats, and that this induction may be associated directly or indirectly with elevated plasma ketone levels.

The pituitary mass after transsphenoidal hypophysectomy

To understand the natural changes in the CT appearance of a pituitary mass after transsphenoidal hypophysectomy of a pituitary tumor, we obtained CT follow-up studies in 12 patients with pituitary adenoma. The heights of the pituitary masses on the coronal sections of each CT study were measured. It was found that the height of the pituitary mass did not return to normal immediately after the operation, despite complete removal of the pituitary tumor. Instead, the height gradually returned to normal between 3 and 4 months after the operation. Results of this study suggest that follow-up CT study of pituitary masses is best performed 3-4 months after transsphenoidal hypophysectomy.

Occlusion of arteriovenous malformations of the cavernous sinus via the superior ophthalmic vein

The treatment of five patients with dural arteriovenous malformations (AVMs) of the cavernous sinus via the superior ophthalmic vein (SOV) is reported. The procedure was performed by transcutaneous puncture of the SOV under the guidance of real-time digital subtraction angiography. Complete resolution of the ocular symptoms was achieved in all cases. Angiograms after embolization showed complete obliteration of the malformation in four cases and partial obliteration in one. This method can cure dural AVMs of the cavernous sinus, with preservation of blood flow in the internal carotid artery. It is particularly indicated when the SOV is enlarged and when (1) dural AVMs of the cavernous sinus are fed by small branches of the internal carotid artery or direct carotid cavernous fistulas with small tears; (2) dural AVMs of the cavernous sinus are fed by multiple branches from both the internal and external carotid arteries, one or both sides; or (3) dural AVMs of the cavernous sinus or direct carotid cavernous fistulas recur after trapping of the internal carotid artery. Transcutaneous puncture and catheterization of the SOV was performed safely with the aid of digital subtraction angiography. The SOV approach was able to treat the fistula with preservation of the internal carotid artery.

Microsurgical vasoepididymostomy to corpus epididymidis in treatment of inflammatory obstructive azoospermia

A unilateral microsurgical vasoepididymostomy utilizing 35 mm of epididymis was performed in a patient with postinflammatory epididymal obstruction. Success was verified with multiple semen analyses, the hamster egg penetration test, and a pregnancy. These results demonstrate that surgical bypass of inflammatory tubal obstruction in the distal epididymis can result in the return of normal epididymal function and fertility.

Toxicity domain in presynaptically toxic phospholipase A2 of snake venom

About 42 complete amino-acid sequences of phospholipases A2 (phosphatidylcholine 2-acylhydrolase, EC 3.1.1.4) are known, including those of 13 presynaptically toxic enzymes, but the structural features responsible for the neurotoxicity and distinguishing the toxins from the non-neurotoxic enzymes are far from being clear. In this study, we examined the charged-residue distributions and hydrophobic characteristics based on the sequence data and the predicted tertiary structure and proposed a possible toxicity domain. We found that the presynaptically toxic enzymes have three or four more basic amino-acid residues than the non-neurotoxic enzymes at positions 59, 60, 65, 70-73 and 97 or 98. These residues appear to cluster near the surface region at the N-terminal side. The cationic nature of this basic cluster in the toxin is enhanced by the alpha-amino group of the N-terminus and the dipole moment of helices 96-110 and 1-10. Moreover, these toxic-site residues are usually associated with hydrophobic regions at 1-7, 64-81 and 97-109.

Cloning and sequencing of a carp beta s-crystallin cDNA

The mRNAs were extracted from common carp (Cyprinus carpio) lenses, purified, reverse transcribed, dC tailed and cloned into Escherichia coli with pBR322 as vector. The cloning efficiency was around 1 X 10(7) colonies per micrograms of mRNA. A clone (pC20) was found by hybrid-arrested to contain the cDNA related to carp crystallins. However, comparison of the derived amino-acid sequence with bovine gamma-II and beta s-crystallins indicates that this carp crystallin sequence resembles closely the bovine beta s-crystallin and should be better classified as such except that this fish sequence does not contain the N-terminal 'arm' of four amino-acid residues present in bovine beta s-crystallin.

Electroelution of DNA and protein from polyacrylamide and agarose gels

An electroelution method is described for the recovery of DNA and protein from agarose or polyacrylamide gels. The samples to be electroeluted are compartmentalized in a modified microcentrifuge tube fitted with dialysis membranes. This procedure is simple, rapid, inexpensive and efficient. Within 30 min to 2 hrs, the recovery of the sample is nearly quantitative. DNA fragments recovered can be directly subjected to DNA sequence analysis or enzymatic reactions after ethanol precipitation. Proteins can also be recovered after separation by acrylamide gel in the presence or absence of detergents and be ready for further analysis.

Spinal cord proliferative sparganosis in Taiwan: a case report

A 43-year-old woman suffered from low back pain and bilateral footdrop. A cisternal myelogram unexpected revealed multiple filing defects in the spinal canal extending from the lower cervical region to the caudal equina. Diagnostic exploration revealed numerous cystic organisms adhering to the spinal cord and nerve roots. Histopathological examination showed these organisms to be proliferative sparganum cestode larvae. Although these cestode larval infections have been reported a dozen times in humans from various parts of the world, this is probably the first reported case of spinal cord infection.

Preclinical and clinical pharmacokinetics of pirmenol

Metabolic disposition and pharmacokinetics of pirmenol were studied in laboratory animals and in patients with premature ventricular beats. After intravenous administration, pirmenol pharmacokinetics were adequately characterized by a 2-compartment body model with elimination half-lives of 3 to 4 hours in animals and 6 to 9 hours in patients. Oral absorption of pirmenol was complete and devoid of significant first-pass metabolism. Systemic oral bioavailability averaged 87% in humans. Pirmenol was 83% to 90% bound to human plasma proteins. Animal studies showed that pirmenol was widely distributed in tissues resulting in higher drug concentrations in tissue than in plasma. Pirmenol was partly eliminated as unchanged drug and partly metabolized. Tracer studies in animals showed that approximately 40% to 50% of the administered radioactive dose was excreted in the urine and the remainder in the feces. The latter route was due to excretion of radioactivity in the bile. Evidence of enterohepatic recycling was established in bile duct-cannulated monkeys. Approximately 23% to 31% of the administered pirmenol dose was recovered unchanged in human urine.

Evaluation of a nomogram for estimating the rate of phenytoin accumulation

This study evaluated a nomogram designed to identify a subgroup of the patients whose serum phenytoin concentrations are near steady state at a given time after initiation of therapy. A sample of 95 adult subjects with reported values of Vmax and Km was pooled from the literature, and computer simulations of phenytoin accumulation for 15 days after initiation of phenytoin acid at 300 mg/day were performed. Simulated serum concentrations on days 5, 10, and 15 were used to identify subjects who were predicted by the nomogram to be at greater than or equal to 83% of steady state, and these results were compared with those expected from the Michaelis-Menten model. In the simulations, 42, 62, and 66 subjects reached greater than or equal to 83% of steady state by days 5, 10, and 15, respectively. The nomogram correctly identified 13 (31.0%), 33 (53.2%), and 43 (65.2%) of these individuals, respectively. The frequency of erroneous predictions was low, even in subjects whose Km and volume of distribution were outside the limits set in the development of the nomogram. Use of a nomogram such as this would help a subgroup of patients to attain a desired serum phenytoin concentration earlier in therapy and with fewer serum phenytoin determinations than would otherwise be required. It would also prevent premature increases in phenytoin dose in patients whose serum concentration is still rising.

Interindividual variation in the extent and rate of phenytoin accumulation

Steady-state serum phenytoin concentration (Css) is known to increase nonlinearly with dose, but it is less well recognized that the rate of phenytoin accumulation is also dose dependent. This stimulation study estimated the extent and rate of phenytoin accumulation in a sample of 95 adult subjects, with known values of Vmax and Km, pooled from the literature. Simulations were done using a Michaelis-Menten model and phenytoin sodium doses of 200, 300, and 400 mg/day. The distributions of Css and the time required to reach 90% of steady state (T90) became increasingly positively skewed as dose was increased. The T90 and Css were positively correlated (r greater than or equal to 0.8880, p less than 0.00001) and subjects reached 90% or more of Css more slowly as the initial phenytoin dose was increased. At an initial dose of 300 mg/day of phenytoin sodium, mean Css was 11.0 +/- 9.10 micrograms/ml (median, 7.62 micrograms/ml), and mean T90 was 12.2 +/- 15.4 days (median, 5.98 days). Only 25.3% of the subjects would be expected to achieve therapeutic serum concentrations (10-20 micrograms/ml) on this dose, and 88.4% would reach 0.9 Css within 30 days. Phenytoin dosage must be individualized to achieve concentrations of 10-20 micrograms/ml. Multiple serum phenytoin determinations during the first 30 days or more are required to determine that steady state has been reached, but these need not be done more often than once a week.

Metabolic disposition of Rolziracetam in laboratory animals

The metabolic disposition of [14C]-labeled Rolziracetam (CI-911) was studied in rhesus monkeys, beagle dogs, and Wistar rats after both p.o. and i.v. doses. Intravenously administered CI-911 was rapidly eliminated from systemic circulation with an apparent elimination half-life of less than 25 min. Plasma radioactivity was 10-20 times higher than that of parent drug and persisted much longer. After oral doses, only traces of intact drug were detected in plasma, whereas total radioactivity reached peak concentrations within 0.5-1 h indicating rapid absorption. The extent of absorption determined from plasma radioactivity and urinary excretion data was 90% or better. Tissue distribution of radioactivity in rats showed the highest concentrations in the liver and kidneys (12-30 times greater than plasma levels) with decreasing levels in the lungs, gonads, heart, spleen, muscle, and brain. Urinary excretion accounted for nearly 90% of the administered dose while fecal recovery was less than 5%. The sole metabolite present in plasma, tissues, and urine was identified as 5-oxo-2-pyrrolidinepropanoic acid (PD 106,687).

Electron density profile of two-dimensionally crystalline membranous cytochrome c oxidase at low resolution

Unilamellar vesicles of membranous cytochrome c oxidase have been isolated whose distribution of protein in the membrane plane was predominantly crystalline. The vesicles were collapsed via controlled partial dehydration, resulting, at first, in the formation of unoriented, mostly unstacked, membrane pairs. Further controlled partial dehydration resulted in the formation of oriented multilayers of stacks of membrane pairs, retaining the in-plane crystallinity. The above were monitored by electron microscopy and x-ray diffraction. Analysis of the x-ray diffraction from unoriented, unstacked membrane pairs by two independent methods provided the membrane electron density profile to 30 A resolution.

Physicochemical characterization of lens crystallins from the carp and biochemical comparison with other vertebrate and invertebrate crystallins

Lens crystallins were isolated from the homogenate of carp (Cyprinus carpio) eye lenses by gel permeation chromatography and characterized by gel electrophoresis, immunodiffusion, amino acid analysis, circular dichroism, and protein sequence analysis. Three well-defined fractions corresponding to alpha/beta-, beta-, and gamma-crystallins were obtained in relative weight percentages of 26, 22, and 52%. The native molecular masses of the purified fractions were determined to be 410, 60, and 20 kDa, respectively. The polypeptide compositions as determined by SDS gel electrophoresis revealed the substantial presence of beta-crystallin polypeptides in the alpha-crystallin fraction; this is also evident in the fractionation of amphibian crystallins but is not common in the case of higher classes of vertebrates. The circular dichroism spectra indicate a predominant beta-sheet structure in all three fractions, albeit with some contribution of alpha-helical structure in the gamma-crystallin, the amino acid composition of which bears a resemblance to that of squid crystallin. Sequence comparison of carp gamma-crystallin with frog and calf gamma-crystallins indicates a high degree of homology in their N-terminal segments despite the dissimilarity of amino acid compositions and weak immunological cross-reactivity.

Non-obstructive idiopathic pachymeningitis cervicalis hypertrophica

Two young men had similar nonobstructive idiopathic pachymeningitis cervicalis hypertrophica, causing chronic (13 and 11 years respectively) C8-T1 radiculomyelopathy proved by surgical and pathological findings. The preoperative Queckenstedt tests and myelography showed no evidence of CSF obstruction. These unusual findings contrast with previous reports which all described complete or at least partial, block. The findings on metrizamide computed tomogram have not been described before. In the two patients it revealed diffuse cord atrophy from C7 to T2 and hemiatrophy with lateral beaking from C4 to C7. The patients benefited from multiple transverse durotomies. The main pathogenesis of the cord atrophy was the compromizing of feeding radicular arteries rather than direct compression.

Characterization of lens crystallins and their mRNA from the carp lenses

Crystallins from carp eye lenses have been isolated and characterized by gel permeation chromatography, SDS-gel electrophoresis, immunodiffusion and amino acid analysis. gamma-Crystallin is the most abundant class of crystallins and constitutes over 55% of the total lens cytoplasmic proteins. It is immunologically distinct from the alpha- and beta-crystallins isolated from the same lens and its antiserum shows a very weak cross-reaction to total pig lens antigens. Comparison of the amino acid compositions of carp gamma-crystallin with those of bovine gamma-II, haddock gamma- and squid crystallins indicates that gamma-crystallin from the carp is very closely related to that of the haddock, and probably also related to the invertebrate squid crystallin. In vitro translation of total mRNAs isolated from carp lenses confirms the predominant existence of gamma-crystallin. The genomic characterization of carp crystallin genes should provide some insight into the mechanism of crystallin evolution in general.

Effect of butalbital and phenobarbital pretreatment on antipyrine clearance in the rat

The disposition kinetics of antipyrine after a single i.v. dose (75 mg/kg) of [14C]antipyrine were examined in control rats and in rats pretreated with butalbital and phenobarbital. Blood antipyrine data indicated that daily administration of phenobarbital (50 mg/kg) for 14 days resulted in significantly more rapid elimination of antipyrine than that observed after equal doses of butalbital, which was in turn significantly faster than the control values. Results of additional antipyrine tests after phenobarbital pretreatment for 2 and 5 days showed considerable enzyme induction after only 2 days of exposure to phenobarbital; the mean antipyrine clearance after the 2-day pretreatment was not significantly different from those after the 5- and 14-day pretreatments. The data suggested that the maximum increase in antipyrine clearance, ca. 190% of the control value, was achieved after approximately 5 daily doses of phenobarbital and maintained until the end of the 14-day pretreatment period. The subsequent decline in the induced enzyme activity, assessed by the antipyrine clearance values on days 1, 3, 6, and 9 post-phenobarbital treatment, appeared to be mono-exponential with a half-time of 3.8 days. Thus, the enzyme activity would return to baseline at ca. 15 days after the last dose of phenobarbital. In these studies, consistent increases in liver weight with increasing antipyrine clearance were observed, while no apparent relationship between antipyrine distribution volume and barbiturate pretreatment was found.

Effect of difluoromethylornithine on host and tumor polyamine metabolism during total parenteral nutrition

Clinical and experimental data suggest that erythrocyte (RBC) polyamine (PA) levels are markers of tumor proliferation during total parenteral nutrition (TPN). The purpose of this experiment was to determine whether the inhibition of PA synthesis during TPN was greater in tumors than in normal host tissue. Rats bearing a subcutaneous fibrosarcoma were randomized to receive a chow diet (n = 5), TPN (n = 5), or TPN + difluoromethylornithine (DFMO) (an irreversible inhibitor of ornithine decarboxylase (ODC), at 1000 mg/kg body wt/day n = 4) for 6 days by continuous central venous infusion. TPN + DFMO resulted in a higher plasma albumin level and lower tumor ODC activity compared with chow feeding or TPN. Liver ODC activity was similar for the chow fed, TPN, and TPN + DFMO groups. RBC putrescine, tumor putrescine, and tumor spermidine levels were significantly lower in the TPN + DFMO group compared with the chow fed and TPN groups. RBC spermidine, RBC spermine, and tumor spermine levels were significantly increased with TPN + DFMO compared with TPN alone. DFMO did not produce diarrhea or weight loss. Increased RBC spermidine may indicate a toxic effect of DFMO on the tumor, resulting in leakage of tumor spermidine into the extracellular space. The data suggest that DFMO during TPN can selectively inhibit tumor PA synthesis and may improve host utilization of nutrients.

Pharmacokinetics of oral pramiracetam in normal volunteers

The pharmacokinetics of pramiracetam, a new, investigational, cognition activator, were assessed in normal male volunteers as part of a clinical tolerance study. In a double-blind, randomized design, two groups of six subjects each received alternating placebo and single 400, 800, 1,200, and 1,600 mg oral doses of pramiracetam after an overnight fast. Mean (+/- SD) peak plasma concentrations of the four dose groups (2.71 +/- 0.54, 5.40 +/- 1.34, 6.13 +/- 0.71, 8.98 +/- 0.71 micrograms/mL) were attained between two to three hours following drug administration. The harmonic mean elimination half-life (4.5-6.5 hours), the mean total body clearance (4.45-4.85 mL/min/kg), the mean renal clearance (1.83-3.00 mL/min/kg), and the mean apparent volume of distribution (1.82-2.94 L/kg) were independent of dose, whereas the peak plasma concentrations and area under the curves increased as a linear function of dose. No significant side effects were observed at any dose level.

Influence of mode of intravenous administration and blood sample collection on rat pharmacokinetic data

The influence of the mode of intravenous dosing and blood sample collection on the pharmacokinetics of 4-[(3-methoxyphenyl)-methyl]-2,2,6,6-tetramethyl-1-oxa-4-aza-2, 6-disilacyclohexane hydrochloride (I) was studied in the rat. Blood samples obtained from the tail and by exsanguination following injection of the 14C-labeled drug into the caudal vein, the jugular vein, and the heart were analyzed for total radioactivity, and the concentration profiles from the different treatments were compared. Dosing and sampling from the tail vein resulted in significantly different blood levels (and related pharmacokinetic parameters) when compared to other methods, probably attributable to a local depot effect. Intracardiac administration tended to cause higher drug levels in the heart than intravenous doses, although no significant differences were found between the respective blood concentrations. The results showed that caudal vein injection is a simple and adequate method of intravenous administration in rats designated for exsanguinated blood and tissue collection. For serial blood sampling in individual animals, the dose may be given via the jugular vein and the blood collected from the cut tail. These methods require little or no surgical preparations and are particularly suitable for prolonged sampling in studies where a relatively large number of animals are involved.

Primary vertebral tumor in an adolescent girl

A 13-year-old girl presented with a 6-month history of back pain, a palpable paravertebral mass, and a left third lumbar radiculopathy. Radiologic studies were consistent with a primary vertebral neoplasm. Posterior biopsy yielded material consistent with osteoblastoma. Anterior tumor excision and vertebral reconstruction followed. Elements consistent with aneurysural bone cyst were present in the resected tumor.

The clinical pharmacokinetics and tolerance of enoxacin in healthy volunteers

In a single-dose tolerance and pharmacokinetics study, enoxacin doses ranging from 200 to 1600 mg were administered orally to 12 healthy normal volunteers. Plasma assays demonstrated rapid absorption of enoxacin with first-order elimination and a half-life averaging 3.4-6.4 h. Renal clearance accounted for approximately 40% of total body clearance of drug. In a second placebo-controlled study, 18 normal volunteers received enoxacin in doses of 400, 600 or 800 mg twice daily for 14 days. Plasma concentrations and pharmacokinetic parameters obtained after the first dose were not significantly different from those observed in the single-dose study. With repeated administration, steady-state plasma concentrations were achieved in three days or less. Steady-state pharmacokinetics were characterized by prompt absorption, first-order elimination, and high urinary concentrations of enoxacin. The most frequently-reported adverse experiences involved the gastro-intestinal tract, the central nervous system, and the skin.