Intranasal absorption of Delta(9)-tetrahydrocannabinol and WIN55,212-2 mesylate in rats.

The aim of this study was to examine the potential of the nasal route for systemic delivery of Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and WIN55,212-2 mesylate. Anesthetized rats were surgically prepared to isolate the nasal cavity, into which Delta(9)-THC (10 mg/kg) or WIN55,212-2 (150 microg/kg) in propylene glycol alone or propylene glycol and ethanol (9:1) were administered. Rats were also administered Delta(9)-THC (1 mg/kg) and WIN55,212-2 (150 microg/kg) intravenously in order to determine absolute bioavailabilities of the nasal doses. Plasma Delta(9)-THC and WIN55,212-2 concentrations were determined by liquid chromatography/mass spectroscopy (LC/MS). The pharmacokinetics of the drugs after intranasal administration was best described by a one-compartment model with an absorption phase. WIN55,212-2 was absorbed more rapidly (T(max)=0.2-0.3h) than Delta(9)-THC (T(max)=1.5-1.6h) and to a higher extent than Delta(9)-THC. Addition of ethanol (10%) to the formulations had no significant effect on the C(max) after nasal administration (p>0.05). Furthermore, it had no significant effect on the absolute bioavailability (F(abs)): F(abs)=6.4+/-2.4% and 9.1+/-3.0% for Delta(9)-THC in propylene glycol, with and without ethanol, respectively. For WIN55,212-2, F(abs)=49.9+/-6.9% (propylene glycol alone) and 56.6+/-14.1% (propylene glycol with 10% ethanol). The results of the study showed that systemic delivery of Delta(9)-tetrahydrocannabinol and WIN55,212-2 could be achieved following nasal administration in rats.

LC-MS method for the estimation of delta8-THC and 11-nor-delta8-THC-9-COOH in plasma.

The aim of the present study was to develop a simple and sensitive LC-MS method for the estimation of delta8-tetrahydrocannabinol (delta8-THC) and its metabolite, 11-nor-delta8-tetrahydrocannabinol-9-carboxylic acid (11-nor-delta8-THC-9-COOH), in guinea pig plasma after topical drug application. The plasma samples were analyzed by LC-MS using negative-mode electrospray ionization detection and a simple liquid-liquid extraction technique. The mean recoveries for delta8-THC and its metabolite, 11-nor-delta8-THC-9-COOH, were 96.6 and 88.2%, respectively. The lower limits of quantification (LLOQ) for delta8-THC and 11-nor-delta8-THC-9-COOH were 3.97 and 7.26 nM, respectively. The topical treatment steady-state plasma concentrations of delta8-THC and 11-nor-delta8-THC-9-COOH were 8.24-27.63 and 19.66-23.17 nM, respectively, with a lag period of 0.3-2.2 h. This assay method is selective, sensitive, and reproducible for the determination of delta8-THC and 11-nor-delta8-THC-9-COOH at low concentrations in small volumes of plasma.

Intranasal delivery of recombinant human parathyroid hormone [hPTH (1-34)], teriparatide in rats.

The aim of this study was to explore the nasal route as an alternative to daily subcutaneous injections of hPTH (1-34). Anesthetized rats were surgically prepared and nasally dosed with aqueous solutions of hPTH (1-34). Plasma samples were assayed by radioimmunoassay and data generated fit to two-(intravenous) and one-(intranasal) compartment pharmacokinetic models using WinNonlin. The toxicity of hPTH (1-34) solution administered to the rats was assessed by screening its effect on transepithelial electrical resistance, potential difference, paracellular marker permeation, tissue viability, and protein leakage using the EpiAirway tissue model. The intranasal absorption of hPTH (1-34) was rapid; the absorption rate constants (alpha) were 33.2+/-24 h(-1) [without bovine serum albumin (BSA)] and 9.8+/-5.1 h(-1) (with 1% BSA). The maximum plasma concentrations (Cmax): 151+/-24 pg/mL (without BSA) and 176+/-37 (with 1% BSA) were attained within approximately 15 min. The intranasal bioavailabilities (Fabs) were 12.1+/-3.4% (without BSA) and 17.6+/-1.5% (with 1% BSA). The hPTH (1-34) formulation administered to the rats had no detrimental effect on the EpiAirway tissue epithelial electrical parameters and functional integrity. Based on the results of this study, the nasal route appears to be a prospective alternative to subcutaneous injections of hPTH (1-34).

Transdermal delivery of the synthetic cannabinoid WIN 55,212-2: in vitro/in vivo correlation.

PURPOSE: The aim of the current investigation was to evaluate the percutaneous absorption of the synthetic cannabinoid WIN 55,212-2 in vitro and in vivo. METHODS: The in vitro permeation studies of WIN 55,212-2 in human skin, hairless guinea pig skin, a polymer membrane with adhesive, and a skin/polymer membrane composite were conducted in flowthrough diffusion cells. The pharmacokinetic parameters for WIN 55,212-2 were determined after intravenous administration and topical application of Hill Top Chambers and transdermal therapeutic systems (TTS) in guinea pigs. RESULTS: The in vitro permeation studies indicated that the flux of WIN 55,212-2 through hairless guinea pig skin was 1.2 times more than that through human skin. The flux of WIN 55,212-2 through human and guinea pig skin was not significantly higher than that through the corresponding skin/polymer membrane composites. The mean guinea pig steady-state plasma concentrations after topical 6.3 cm2 chamber and 14.5 cm2 TTS patch applications were 5.0 ng/ml and 8.6 ng/ml, respectively. CONCLUSIONS: The topical drug treatments provided significant steady-state plasma drug levels for 48 h. The observed in vivo results from the Hill Top Chambers and TTS patches in the guinea pigs were in good agreement with the predicted plasma concentrations from the in vitro data.

In vitro/in vivo correlation studies for transdermal delta 8-THC development.

The present study was carried out in order to develop a transdermal therapeutic system (TTS) for Delta(8)-THC. The in vitro permeability studies of Delta(8)-THC in human skin and hairless guinea pig skin with and without a rate-controlling membrane were conducted in flow-through diffusion cells. Delta(8)-THC pharmacokinetic parameters were determined after topical application of transdermal patches and intravenous administration in guinea pigs. The in vitro results indicated that there was no significant difference in the mean flux or in the permeability coefficient of Delta(8)-THC in human skin versus hairless guinea pig skin. The flux of Delta(8)-THC through the human skin/membrane composite was not significantly lower than that through the hairless guinea pig skin/membrane composite; and the skin controlled the Delta(8)-THC delivery rate. Intravenous doses of Delta(8)-THC followed a two-compartment model with a significant distribution phase. On application of the TTS patch, the plasma concentration of Delta(8)-THC reached a mean steady-state level of 4.4 ng/mL within 1.4 h and was maintained for at least 48 h. Significant amounts of metabolites were observed in the plasma after topical application. The in vitro-study predicted plasma concentration following application of the transdermal patch was in agreement with the observed guinea pig plasma concentrations of Delta(8)-THC.

Assessment of motoneuron excitability using recurrent inhibition and paired reflex depression protocols: a test of reliability.

Motor output may be regulated by both pre- and post-synaptic mechanisms. The purpose of this study was to investigate the reliability of two measurement protocols, which purport to examine spinal mechanisms responsible for gating motoneuron excitability. Nine subjects (aged 29 +/- 5 years) were tested using two soleus H-reflex protocols; 1) recurrent inhibition (RI) and 2) paired reflex depression (PRD). The dependent variable for each protocol was the peak-to-peak amplitude of the conditioned Hoffmann reflex (H-reflex). Seven trials were obtained for each subject under each condition as well as control values to assess test-retest reliability. After all trials were collected the subjects rested for at least five minutes after which the process was repeated. Each subject returned to the lab after a period of no less than 24 hours at which time the process was repeated. Protocol #1: Control reflexes (20% of maximal motor response) were obtained during quiet stance. After obtaining control trials two reflex responses were elicited which were separated by 10 ms on each trial to assess recurrent inhibition (Pierrot-Deseilligny et al., 1976; Bussel and Pierrot-Deseilligny, 1977). Protocol #2: Again a double-pulse technique was used to assess reflex activation history on motoneuron pool output (Trimble et al., 2000). This protocol utilized two reflex stimuli of the same intensity separated by 80 ms. The peak-to-peak amplitude of the control, RI conditioned and PRD conditioned H-reflexes exhibited intraclass reliability estimates of .97, .97 and .93 respectively. To achieve a reliability of rI > or = .80, it is recommended that a minimum of 2 trials be used for the RI protocol and that 4 trials be used for the PRD protocol. The results indicate that both techniques provide a means to objectively and reliably measure spinal mechanisms for gating motoneuron pool output.

Regulation of motor output between young and elderly subjects.

OBJECTIVES: Considerable information exists concerning the differences in motoneuron pool (MP) excitability between young and elderly subjects. A recent study demonstrated decreased heteronymous Ia facilitation with aging, suggesting increased presynaptic inhibition (PI) with increasing age as a mechanism for this change (Morita et al., Exp Brain Res 104 (1995) 167). It has been suggested that during voluntary movement, supraspinal, and possibly, segmental mechanisms (Hultborn et al., J Physiol 389 (1987) 757) modulate this inhibition. It is theorized that PI can modulate the recruitment gain of the MP during movement without altering the excitability of the motoneurons. Therefore, the purpose of this study was to examine the roles of PI and volitional volleys in modulating MP output in young and elderly subjects. METHODS: Twenty apparently healthy females participated in this study, 10 college aged (mean age, 22.4+/-2.8 years) and 10 independent, community dwelling elderly (mean age, 77.6+/-5.4 years). All subjects were tested in a semi-recumbent position. H-reflexes were elicited at rest, and at 10 and 20% of maximal voluntary contraction. To assess MP output, background electromyography (EMG) was monitored prior to stimulation. The stimulus intensity was adjusted during volitional contractions to ensure similar control reflexes (25% of the maximal motor response (M-max)) at each level of contraction. RESULTS: Control reflexes at each level of volitional contraction (rest, 10 and 20%) were similar for both groups. To assess PI and to estimate the extent to which a change in the H-reflex amplitude reflects a change in MP gating, the common peroneal nerve was stimulated at 1.5 times the motor threshold 100 ms prior to stimulation of the tibial nerve. Significantly greater PI was observed for the young subjects at rest (5 vs. 13% M-max). At both 10 and 20% levels of voluntary contraction, the conditioned reflex was significantly different from rest for the young subjects. The elderly subjects, in contrast, failed to modulate the conditioned reflex until the 20% of maximal voluntary contraction (MVC) condition. When examining the recruitment gain in the MP during the PI condition (H-reflex amplitude as a function of EMG levels), a significant group effect was observed, with the young subjects demonstrating significantly higher PI gain. CONCLUSIONS: These results indicate differential control of MP output (e.g. PI vs. volitional volleys) in young and elderly subjects.

Velocity training induces power-specific adaptations in highly functioning older adults.

OBJECTIVE: To test the efficacy of high-velocity training in healthy older persons. DESIGN: A 12-week randomized trial, with subjects blocked for gender and residence, comparing high-velocity resistance training with a self-paced walking program. SETTING: Retirement community. PARTICIPANTS: Forty-three volunteers over the age of 70 years. INTERVENTION: Power group: high-velocity leg exercises 3 times weekly with weekly increases in resistance combined with 45 minutes of moderate, nonresistance exercise weekly. Walking group: moderate intensity exercise 30 minutes daily, 6 days weekly. MAIN OUTCOME MEASURES: Variables measured included leg press peak power and leg extensor strength. Functional performance outcomes included: 6-minute walk distance, Short Physical Performance Battery, Physical Performance Test, and Medical Outcomes Study Short-Form Health Survey. RESULTS: Peak power improved 22% (p =.004) in the power group (3.7 +/- 1.0 W/kg to 4.5 +/- 1.4 W/kg) but did not change in the walking group (3.99 +/-.76 W/kg to 3.65 +/-.94 W/kg). Leg extensor power at resistance of 50%, 60%, and 70% of body weight increased 50%, 77%, and 141%, respectively, in the power group (p <.0001, repeated-measures analysis of variance). Strength improved 22% in the power-trained individuals and 12% in the walkers (p <.0001). Training did not improve functional task performance in either group. One subject developed a radiculopathy during training. CONCLUSIONS: Resistance training focusing on speed of movement improved leg power and maximal strength substantially, but did not improve functional performance in healthy high-functioning older volunteers.

Environmental changes in soleus H-reflex excitability in young and elderly subjects.

The purpose of this study was to examine the role of task complexity on soleus H-reflex modulation in young and elderly subjects. Twelve young (mean age = 29.2yrs) and 10 elderly (mean age = 75.1 yrs) apparently healthy individuals were examined under four experimental conditions: (1) eyes open on normal floor surface; (2) eyes open on foam floor surface; (3) eyes closed on normal floor surface; and (4) eyes closed on foam surface. Under each condition, soleus H-reflexes, and background electromyography (EMG) (40 ms window prior to stimulation in both the soleus and the tibialis anterior) were recorded. Postural sway in each condition was also assessed using a Kistler force platform. Results indicated differential reflex modulation between young and elderly subjects. Specifically, young subjects depressed the amplitude of the reflex as task complexity was increased. Elderly subjects, on the other hand, increased the amplitude of the H-reflex when utilizing visual cues, but decreased H-reflex amplitude when vision was occluded. Postural sway in both groups increased as task complexity was increased. There existed a significant difference in the relationship between tibialis anterior activation and soleus H-reflex between the two groups. These results demonstrate differential reflex adjustments between young and elderly subjects as task complexity is increased, and may provide useful information pertaining to postural control in the elderly.

Age differences in postural sway during volitional head movement.

OBJECTIVE: To examine the role of a volitional self-paced head-turn movement on the postural sway characteristics of healthy young and elderly subjects. DESIGN: Cross-sectional design. SETTING: Motor control research laboratory. SUBJECTS: Ten young adults and 10 elderly subjects. MAIN OUTCOME MEASURES: Postural sway characteristics of each subject were examined using a Kistler force platform. Each subject was tested under four experimental conditions: (1) static postural sway with vision; (2) static postural sway without vision; (3) postural sway with vision and self-paced head-turn movement; and (4) postural sway with no vision and a self-paced head-turn movement. Subjects performed six 15-second trials in each experimental condition. Dependent variables analyzed on each trial were mean sway amplitude (in millimeters), sagittal sway standard deviation, lateral sway standard deviation, and frequency of sway (in hertz). RESULTS: During the static conditions (e.g., no voluntary movement), the young subjects produced significantly less postural sway than the elderly in both the vision condition (sway amplitude in the young, 3.80 mm; in the elderly, 4.89 mm) and the no-vision condition (young, 5.44 mm; elderly, 5.95 mm). This increased sway was the result of greater lateral sway in the elderly for the vision condition (3.73 vs. 2.68 mm), and greater sagittal sway for the elderly in the no-vision condition (5.55 vs. 4.70 mm). There were no significant differences between the groups in the frequency of sway. When asked to initiate and complete the head-turn, elderly subjects significantly increased their mean sway amplitude and decreased their frequency of sway, whereas the young subjects did not significantly alter their postural sway profiles. CONCLUSIONS: These results demonstrate different postural sway control strategies for young and elderly subjects when asked to perform volitional movements.

Inhibition of the soleus H-reflex in standing man.

There exists evidence to support the notion that the segmental reflex system is not fixed and inflexible, but rather is highly modifiable under a variety of circumstances. In this study the H-wave and M-wave recruitment curves were obtained from 19 subjects, utilizing the procedures outlined by Hugon. Each subject was tested on one day under two randomly administered conditions: (1) standing; and (2) prone. Once in place, the recording and stimulating electrodes were not removed until the completion of the study, to ensure that exact placement was maintained. A percutaneous electrical stimulus (1 ms pulse) was utilized to elicit the pulse. The current was monitored with a current probe, and was increased in 2 mA increments from zero until a maximal M-wave was obtained. An analysis of variance revealed significant increases in the amplitude of the H-wave (P < 0.05) when the subject was prone with no significant increases in the M-wave. The results indicate significantly higher H/M ratios with the subjects in the prone position. Therefore, it is concluded that H-reflex amplitude is tonically depressed when the subject is maintaining a standing position.

Procurement for a comprehensive cancer center.

The director of materials management services at M.D. Anderson is a position of endless opportunities, as well as continual challenges. The procurement process provides the opportunity to be an integral part of a team that has made a significant difference to many of the patients in the areas of cancer prevention, education, detection, diagnosis, treatment, cure, and rehabilitation. All involved in health care purchasing derive a personal fulfillment not available to purchasers in other industries. At MDA, however, this goes even one step further, as our department supports a team in the battle against cancer--a battle that affects nearly every household in America today. MDA can state that more than half of all patients treated are considered cured, and that is certainly a great team with which to be associated. But even more exciting are the years to come, as materiel management services supports the M.D. Anderson mission of eliminating cancer and allied diseases as significant health problems throughout the world.

Identification and partial characterization of sperm receptor associated with the newly formed fertilization envelope from sea urchin eggs.

Prior studies from this laboratory have identified a proteoglycan-like component of high molecular weight from the surface of the egg of the sea urchin Strongylocentrotus purpuratus that serves as a receptor for sperm. In the present study, a glycoconjugate has been isolated from uncrosslinked fertilization envelopes prepared from eggs activated by treatment with ionophore. Based on its high molecular weight (greater than 5 X 10(6)) and its ability to inhibit fertilization by acrosome-reacted sperm, this glycoconjugate has the properties of the previously described sperm receptor. Components of the fertilization envelope of lower molecular weight (less than 10(6)) showed little or no ability to inhibit fertilization.

A monoclonal antibody inhibits calcium accumulation and skeleton formation in cultured embryonic cells of the sea urchin.

The assembly of the spicules (primitive skeleton) of the sea urchin embryo is being studied in primary mesenchyme cells cultured in vitro. A monoclonal antibody (1223) has been prepared that inhibits the deposition of CaCO3 into the spicules. This antibody reacts with a 130,000 Mr cell-surface protein that is concentrated on the surface of approximately 5% of the cells of dissociated gastrula stage embryos. When primary mesenchyme cells in the embryo or cells cultured in vitro are examined, the 1223 antigen is detected on the surface of the cells and on the extracellular material associated with the spicule. We conclude that the 1223 antibody recognizes a cell-surface protein that plays an essential role in spicule formation.