Induction of carcinoembryonic antigen expression in a three-dimensional culture system.

MIP-101 is a poorly differentiated human colon carcinoma cell line established from ascites that produces minimal amounts of carcinoembryonic antigen (CEA), a 180 kDa glycoprotein tumor marker, and nonspecific cross-reacting antigen (NCA), a related protein that has 50 and 90 kDa isoforms, in monolayer culture. However, MIP-101 produces CEA when implanted into the peritoneum of nude mice but not when implanted into subcutaneous tissue. We tested whether three-dimensional (3D) growth was a sufficient stimulus to produce CEA and NCA 50/90 in MIP-101 cells, because cells grow in 3D in vivo rather than in two-dimensions (2D) as occurs in monolayer cultures. To do this, MIP-101 cells were cultured on microcarrier beads in 3D cultures, either in static cultures as nonadherent aggregates or under dynamic conditions in a NASA-designed low shear stress bioreactor. MIP-101 cells proliferated well under all three conditions and increased CEA and NCA production three- to four-fold when grown in 3D cultures compared to MIP-101 cells growing logarithmically in monolayers. These results suggest that 3D growth in vitro simulates tumor function in vivo and that 3D growth by itself may enhance production of molecules that are associated with the metastatic process.

Diagnostic ultrasound for suspected appendicitis: does the added cost produce a better outcome?

Acute appendicitis is one of the most common abdominal surgical emergencies in North America. Although the treatment of appendicitis has remained the same for over 250 years, diagnostic techniques have changed immensely. Most recently, graded compression ultrasonography has received much support. In an attempt to determine whether ultrasonography has improved the outcome in acute appendicitis, we retrospectively reviewed the records of all patients undergoing appendectomy and/or ultrasound for suspected appendicitis during two separate 12-month periods. We began using ultrasound in the diagnosis of appendicitis in 1987; therefore, 1986 was used as our pre-ultrasound year; 1989 was used as our comparison year because ultrasound had become widely applied in the diagnosis of acute appendicitis by this time. Data was tabulated on all patients undergoing appendectomy in both study years, as well as those also undergoing ultrasonography in 1989. The populations in 1986 and 1989 were similar for all data tabulated. The diagnostic accuracy rate actually decreased after the implementation of ultrasonography (85.6% vs 77.0%, P < 0.05). This trend was seen in both male and female patients, reaching statistical significance in the male population (P < 0.05). The incidence of perforation and complications were not statistically decreased after the implementation of ultrasound. Ultrasound did not decrease the length of hospital stay, and in addition added approximately $48,000 to the treatment cost of appendicitis in 1989. Thus, despite adding cost, ultrasonography for appendicitis did not improve our ability to diagnose or accurately treat appendicitis.

Second thoracic sympathetic ganglionectomy in sympathetically maintained pain.

Twenty-four individuals with sympathetically maintained pain were treated by posterior paravertebral T2 sympathectomy following transient response to sympathetic nerve blockade. Eight surgical patients (33.4%) had causalgia, and 16 patients (66.4%) suffered with reflex sympathetic dystrophy. Overall, physical evidence of improvement was noted in 87% of surgical patients, with subjective improvement in 71%. Reflex sympathetic dystrophy patients fared better than those with causalgia. Complications were minor. The techniques employed appear safe and effective; a multidisciplinary approach with neurosurgery, physiatry, anesthesiology, psychology, and allied health services is recommended.

Massive extravasation of traumatically ruptured buttock silicone prosthesis.

Although requests for gluteal implants are unusual in the United States, the use of silicone implants for buttock cosmesis has been described. Complications of this procedure have rarely been reported. There are no reports of long-term follow-up in these patients. This report describes the traumatic rupture of a silicone buttock implant nine years after initial surgical placement. Massive silicone extravasation and migration, along with silicone granuloma formation, occurred. The contralateral implant remained intact, functional, and cosmetically acceptable. The surgical approach and repair of this injury is outlined and discussed. We conclude that early surgical treatment of extravasation injuries is needed and that buttock reconstruction with implants can be useful, but close follow-up is needed. We also suggest there is a need to evaluate alternative materials for use in this procedure.

Responses of septal theta-on and theta-off cells to activation of the dorsomedial-posterior hypothalamic region.

The effect of different levels of electrical stimulation of the dorsomedial-posterior hypothalamic region, on the discharge properties of septal theta-on and theta-off cells, was investigated in urethane-anesthetized rats. In the present sample of 45 cells recorded in the medial septum/ventral limb of the diagonal band of Broca, 43 of the 45 (96%) were affected by the stimulation. The majority of theta-on cells were intensely activated by this stimulation (two were inhibited) and all theta-off cells were inhibited (ranging from partial to complete inhibition). Stimulation did not change a cell's classification as "on" or "off," nor did it alter its discharge pattern (phasic or tonic). Stimulation did have a profound effect on phasic nonlinear theta-on cells. Phasic nonlinear theta-on cells, by definition, did not alter their discharge rate in relation to the increasing frequency of spontaneously occurring or tail-pinch-induced theta. However, stimulation of the dorsomedial-posterior hypothalamus resulted in 11 out of 13 (85%) of the phasic nonlinear cells increasing their discharge rates in relation to the increasing frequency of the hypothalamically induced theta (i.e., became linear). Stimulation had no effect on two cells classified as unrelated to theta.

Antinociceptive activity of pentamorphone, a 14-beta-aminomorphinone derivative, compared to fentanyl and morphine.

The analgesic potency of pentamorphone, a 14-beta-aminomorphinone derivative, was compared to that of fentanyl and morphine by examining quantal dose-effect curves generated from data obtained in the mouse hot plate, rabbit tooth-pulp, and dog tail clamp tests. Onset and duration of antinociceptive effects were also compared. The ED50 values (mg/kg) were determined in mice for pentamorphone (0.0039), fentanyl (0.016), and morphine (7.3). In the rabbit tooth pulp test the ED50 values were 0.0009 mg/kg for pentamorphone, 0.0074 mg/kg for fentanyl, and 1.1 mg/kg for morphine; in the dog tail clamp test these values were 0.012 mg/kg for pentamorphone and 0.018 mg/kg for fentanyl. Duration of action (defined as the time until response to tooth pulp stimulation declined to 50% of maximum possible effect [MPE]) was 10 min with twice the IV ED50 for pentamorphone in mice. This duration was similar to that of the equipotent dose of fentanyl but much shorter than the duration of an equipotent potent dose of morphine (60 min). The duration in rabbits of the ED98 (IV) dose of pentamorphone was 65 min compared to 35 min for an equipotent dose of fentanyl and 200 min for morphine. Intramuscular doses of pentamorphone had significantly faster onset and shorter duration times than equipotent doses of morphine in both mice and rabbits. Pretreatment with naloxone in mice and rabbits attenuated the development of the antinociceptive effects of pentamorphone. This study shows that pentamorphone is a potent analgesic with a duration of action similar to that of fentanyl.

The classification of medial septum-diagonal band cells as theta-on or theta-off in relation to hippocampal EEG states.

The discharge patterns of cells located in the medial septum (MS)/vertical limb of the Diagonal Band of Broca (vDBB) were recorded simultaneously with hippocampal formation large amplitude irregular activity (LIA), or theta, in urethane-anesthetized rats. The main conclusion was that the majority of cells in the MS/vDBB were theta-related and could be classified according to the same scheme developed for theta-related cells in the hippocampal formation. That is, cells were classified as theta-on or theta-off, with subtypes defined as tonic or phasic, linear or non-linear. The discharge properties of hippocampal and MS/vDBB cell populations were compared. It was argued that this classification scheme encompassed all the crucial properties of theta-related cells in the hippocampal formation and the MS/vDBB. An alternative model to the septal pacemaker hypothesis, concerning the role of the medial septum in the generation of hippocampal formation theta activity, was presented and discussed.

Hippocampal formation neurons code the level of activation of the cholinergic septohippocampal pathway.

In these experiments, differing levels of activation of the cholinergic septohippocampal pathway, as reflected by shifts in type 2 slow wave theta frequency recorded in the hippocampal formation, were studied in urethane-anesthetized rats. The purpose was to determine whether the discharge rates of cells in the hippocampal formation varied in any systematic way with the frequency shifts produced during spontaneous theta and by stimulation of the dorsomedial-posterior hypothalamic region. Linear regression analysis revealed that a class of neurons called theta-on cells precisely coded the level of activation of the septohippocampal pathway through their discharge rates. Administration of atropine sulfate abolished this coding. A second class of neurons called theta-off cells were shown to have reciprocal relationships with theta-on cells. Implications for the sensorimotor model of hippocampal formation theta subsystems were discussed.

A rabbit tooth-pulp assay to determine ED50 values and duration of action of analgesics.

The rabbit tooth-pulp assay is well established as a standard and reliable method to test for analgesic activity of drugs. Traditional methods to compare potencies of narcotic analgesics have been to establish ED50 values from rodent hot-plate and tail-flick tests. We describe a modification of the tooth-pulp assay with the use of a microcomputer to generate ED50 values based on "all or none" quantal responses and to evaluate durations of action, with the use of relatively few animals to test several drugs. The potencies of morphine, fentanyl, and alfentanil were established and compared to those from the mouse hot-plate assay. The rank order of potencies were the same and the absolute values were consistently lower. The ED50 value of pentazocine was determined with the tooth-pulp assay but could not be determined with the standard mouse hot-plate assay. The assay provides an additional, reliable, and sensitive method to generate ED50 values and to evaluate durations of action of narcotic analgesics.

levo-Alpha-acetylmethadol and metabolites: some effects on schedule-controlled behavior in the rat.

The behavioral effects of acute IP administration of 1-alpha-acetylmethadol, its metabolites, 1-alpha-noracetylmethadol and 1-alpha-dinoracetylmethadol, and morphine were studied in the rat using behavior controlled by a fixed-interval schedule of food reinforcement. Administraiton of all compounds produced a dose-related decrease in response rate. The metabolites were approximately three to four times the potency of the parent compound which was approximately five times the potency of morphine. Data obtained from cumulative response records suggested that the onset of effects for the metabolites was more rapid than for the parent compound.

Reinforcing properties of intravenous procaine in rhesus monkeys.

The lever pressing behavior of rhesus monkeys was maintained by a fixed ratio 10 schedule of intravenous cocaine (3 monkeys) or codeine (2 monkeys) injections during 2 hour sessions. Saline or various doses of procaine hydrochloride were substituted for the baseline reinforcer for 6 consecutive sessions. Each substitution was separated by 3 or more days of cocaine or codeine reinforced responding. At one or more doses, procaine substitution resulted in response rates higher than saline control in all 5 animals. High response rates (greater than 30 injections per session) were obtained in 4 of the 5 monkeys. In addition, procaine self-administration was studied in two naive monkeys given 23 hour per day access to procaine following an initial 10 days of saline contingent operant level responding. At a dose of 0.3 mg/kg/injection, both animals initiated responding for procaine reinforcement. Drug intake varied widely from day to day, however each animal took over 1200 injections per day (over 360 mg/kg) at least once during the 30 days of access. With the exception of decreased food intake, there was little evidence for behavioral toxicity from these doses. Following a second 10 days of saline self-administration, both animals were given access to 3.0 mg/kg/injection procaine. A substantially greater intake of procaine was observed which was associated with marked toxicity.

Schedule-controlled behavior in the morphine-dependent rat.

The behavioral effects of acute and chronic administration of morphine and its withdrawal were studied using schedule-controlled responsing in the rat under a differential reinforcement of low rates of responding (DRL) schedule of food presentation. Acute morphine administration had a biphasic effect on response rate. Low dses (1.8-5.6 mg/kg) tended to produce a small increase and higher doses (10-30 mg/kg) decreased responding. Physical dependence was produced by twice daily injections, with an initial dose of 40 mg/kg/day which was increased by 80 mg/kg/day until reaching 600 mg/kg/day which was continued for 14 days. Throughout chronic administration the pattern of responding remained disrupted resulting in a 27-47 percent decrease in presentations of the reinforcer, while response rate was more variable and generally decreased. The effects of morphine withdrawal lasted 5 days and produced an initial maked decrease in reinforecements per hour and a biphasic change in response rate. A marked decrease in responding early in withdrawal (22.5 hr) was followed by a marked and more prolonged (70.5-118.5 hr) response rate increase.