Maternal behavior in female C57BL/6J and DBA/2J inbred mice

Inbred strains of mice exhibit different patterns of maternal behavior, providing material for studies of genetic influences on the expression of maternal behavior. Beginning 1 day after birth, maternal behavior was recorded daily for 14 days in the first and second litters of C57BL/6J (B6) and DBA/2J (D2) mothers. D2 mice had higher pup survival than B6 mice, and pup survival was higher in both strains in second litters than in first litters. D2 mothers spent more time engaged in maternal behavior, especially resting with, crouching over, and nursing pups than B6 mothers with first litters, but not with second litters. Not all measures of maternal behavior were correlated with pup survival; with both litters, B6 mothers retrieved pups faster than D2 mothers.

Nerve decompression at the wrist in patients with Charcot-Marie-Tooth disease

Studies evaluating the effects of nerve release in patients with Charcot-Marie-Tooth disease have been extremely limited to date. This series attempts to evaluate the clinical and electrophysiologic effect of nerve release at the wrist in a series of patients with this disease. Five patients with documented Charcot-Marie-Tooth disease of the upper extremity were followed clinically and had nerve conduction testing both before and after surgery. This study shows that there was an improvement in both sensory and motor testing after release in a significant proportion of patients (p < 0.05). All patients documented improvement in their sensory latency response postoperatively (100 percent) and most showed improvement in motor latency responses (87 percent). More importantly, however, there seems to be an even greater clinical improvement in preoperative complaints (e.g., paresthesia and pain) in the majority of the extremities that underwent surgery with all patients experiencing initial relief and the majority showing no recurrence (63 percent) at last follow-up. From these results, this relief can be variable, but has lasted for a significant duration postoperatively in the majority, necessitating careful consideration for surgery as a legitimate option for patients with Charcot-Marie-Tooth.

Behavioural studies of MHC-congenic mice

Behavioural studies of MHC-congenic mice and rats have focused primarily on mate choice and the ability to discriminate between strains by their urine odours, but these strains may differ in other behaviours, such as activity and ultrasonic vocalizations. Ivanyi (1978, Proc. Roy. Soc. Lord. 202, 117-158) has reviewed the physiological differences associated with the MHC, many of which could influence behaviour. We have started a systematic study of behavioural development and adult behaviour in MHC-congenic mice. A developmental test battery (growth, rate, locomotion, grooming, eye opening, ultrasonic vocalizations, etc.) was used to examine differences between C57BL/6J vs. B6-H-2bml and C57BL/10SnJ vs. B10.BR/sgSnJ mice. A test battery of spontaneous behaviours (activity, exploration, ultrasonic vocalizations, etc.) was used to examine behavioural differences between adult C57BL/6J vs. B6-H-2bml; and C57BL/10SnJ vs. B10.BR/sgSnJ mice. Differences in development and in adult behaviours between these MHC-congenic strains is discussed in relation to possible neural, endocrine and immune system differences. Future studies will compare MHC-congenic mice on levels of anxiety, sociosexual behaviour and on learning paradigms.

Modulation of nanotube formation by structural modifications of sphingolipids

Galactosylceramides (GalCers) containing nervonoyl (24:1(Delta15(cis))) acyl chains have the capacity to assemble into nanotubular microstructures in excess water (. Biophys. J. 69:1976-1986). To define the structural parameters that modulate nanotube formation, GalCer derivatives were synthesized that contained cis monounsaturated acyl chains with the formula X:1((X-9)). X indicates the total acyl carbon number (24, 22, 20, or 18), and 1 indicates a single cis double bond, the location of which is designated by the superscript (X-9). Deep etching of freeze-fractured 24:1(Delta15(cis)) GalCer dispersions followed by replica production and transmission electron microscopic analysis confirmed nanotube morphology (25-30-nm diameter). Control experiments revealed that tubule formation was promoted by cooling through the main enthalpic phase transition coupled with repetitive freeze-thaw cycling. Imparting a negative charge to the sugar headgroup of 24:1(Delta15)GalCer via sulfate dramatically altered mesomorpholgy and resulted in myelinic-like, multilamellar structures. Removal of the sugar headgroup (24:1(Delta15)Cer) resulted in flattened cylindrical structures with a cochleate appearance. Compared to these large-scale changes in morphology, more subtle changes were induced by structural changes in the acyl chain of 24:1(Delta15)GalCer. 22:1(Delta13)GalCer dispersions consisted of long, smooth tubules (35-40-nm diameters) with a strong tendency to self-align into bundle-like aggregates. In contrast, the microstructures formed by 20:1(Delta11)GalCer resembled helical ribbons with a right-handed twist. Ribbon widths averaged 30-35 nm, with helical pitches of 80-90 nm. 18:1(Delta9)GalCer displayed a variety of morphologies, including large-diameter multilamellar cylinders and liposome-like structures, as well as stacked, plate-like arrays. The results are discussed within the context of current theories of lipid tubule formation.

Mice deficient in endothelial nitric oxide synthase exhibit a selective deficit in hippocampal long-term potentiation

Long-term potentiation, a persistent increase in synaptic efficacy, may require a retrograde signal originating in the postsynaptic cell that induces an increase in presynaptic neurotransmitter release. We have constructed a mouse homozygous for a targeted null mutation in the endothelial isoform of nitric oxide synthase and report that long-term potentiation in the CA1 region of these mice is entirely absent under weak stimulation conditions. Application of a membrane-permeant guanosine-3',5'-cyclic monophosphate analogue during tetanus fails to compensate for this deficit, suggesting that nitric oxide produced by endothelial nitric oxide synthase may affect long-term potentiation through a cascade that does not include guanylyl cyclase. We also report that strong tetanic stimulation can induce robust long-term potentiation in these mice which is not blocked by pharmacological inhibitors of nitric oxide synthase. Furthermore, mice lacking endothelial nitric oxide synthase show no shift in the frequency-response curve for the induction of long-term potentiation. Basal synaptic transmission, paired-pulse facilitation and the electrical properties of CA1 cells in these mice were similar to controls. These results support a selective role for endothelial nitric oxide synthase in long-term potentiation, but also demonstrate that nitric oxide synthase is not involved in this process under all conditions.

Use of free-tissue transfer in the treatment of median sternotomy wound infections: retrospective review

The incidence of sternal wound infection following median sternotomy is 0.4 to 5 percent. Debridement and closure of the wounds with local and regional muscles, such as a pectoralis or a pedicled rectus abdominis, have been the mainstay of surgical treatment. Often, both pectoralis major muscles and the superior portion of a rectus abdominis muscle must be used to close large sternal wounds. Loss of these major muscles can be both debilitating and cosmetically disfiguring. Free-tissue transfer can be employed to limit the amount of tissue needed to fill the sternal defect. The authors present a series of 12 free-tissue transfers used in 11 patients to close large sternal defects in this subset of patients. Total flap loss occurred in one patient. Partial loss of the skin island was noted in three patients. Two patients developed abdominal hernias after rectus abdominis free flaps. Free-tissue transfer offers the ability to close these large wounds, using one muscle, in those patients where pedicled rectus abdominis flaps are not available.

A fluorescence resonance energy transfer approach for monitoring protein-mediated glycolipid transfer between vesicle membranes

A lipid transfer protein, purified from bovine brain (23.7 kDa, 208 amino acids) and specific for glycolipids, has been used to develop a fluorescence resonance energy transfer assay (anthrylvinyl-labeled lipids; energy donors and perylenoyl-labeled lipids; energy acceptors) for monitoring the transfer of lipids between membranes. Small unilamellar vesicles composed of 1 mol% anthrylvinyl-galactosylceramide, 1.5 mol% perylenoyl-triglyceride, and 97.5% 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) served as donor membranes. Acceptor membranes were 100% POPC vesicles. Addition of glycolipid transfer protein to mixtures of donor and acceptor vesicles resulted in increasing emission intensity of anthrylvinyl-galactosylceramide and decreasing emission intensity of the nontransferable perylenoyl-triglyceride as a function of time. The behavior was consistent with anthrylvinyl-galactosylceramide being transferred from donor to acceptor vesicles. The anthrylvinyl and perylenoyl energy transfer pair offers advantages over frequently used energy transfer pairs such as NBD and rhodamine. The anthrylvinyl emission overlaps effectively the perylenoyl excitation spectrum and the fluorescence parameters of the anthrylvinyl fluorophore are nearly independent of the medium polarity. The nonpolar fluorophores are localized in the hydrophobic region of the bilayer thus producing minimal disturbance of the bilayer polar region. Our results indicate that this method is suitable for assay of lipid transfer proteins including mechanistic studies of transfer protein function.

On the mechanism of histaminergic inhibition of glutamate release in the rat dentate gyrus

1. Histaminergic depression of excitatory synaptic transmission in the rat dentate gyrus was investigated using extracellular and whole-cell patch-clamp recording techniques in vitro. 2. Application of histamine (10 microM, 5 min) depressed synaptic transmission in the dentate gyrus for 1 h. This depression was blocked by the selective antagonist of histamine H3 receptors, thioperamide (10 microM). 3. The magnitude of the depression caused by histamine was inversely related to the extracellular Ca2+ concentration. Application of the N-type calcium channel blocker omega-conotoxin (0. 5 or 1 microM) or the P/Q-type calcium channel blocker omega-agatoxin (800 nM) did not prevent depression of synaptic transmission by histamine. 4. The potassium channel blocker 4-aminopyridine (4-AP, 100 microM) enhanced synaptic transmission and reduced the depressant effect of histamine (10 microM). 4-AP reduced the effect of histamine more in 2 mM extracellular calcium than in 4 mM extracellular calcium. 5. Histamine (10 microM) did not affect the amplitude of miniature excitatory postsynaptic currents (mEPSCs) and had only a small effect on their frequency. 6. Histaminergic depression was not blocked by an inhibitor of serine/threonine protein kinases, H7 (100 microM), or by an inhibitor of tyrosine kinases, Lavendustin A (10 microM). 7. Application of adenosine (20 microM) or the adenosine A1 agonist N6-cyclopentyladenosine (CPA, 0.3 microM) completely occluded the effect of histamine (10 microM). 8. We conclude that histamine, acting on histamine H3 receptors, inhibits glutamate release by inhibiting presynaptic calcium entry, via a direct G-protein-mediated inhibition of multiple calcium channels. Histamine H3 receptors and adenosine A1 receptors act upon a common final effector to cause presynaptic inhibition.

Fingertip reconstruction with flaps and nail bed grafts

We retrospectively reviewed the cases of 14 fingertips reconstructed with a combination of local or regional flaps and nail bed grafts, some of which were placed wholly or partially over a de-epithelialized flap. Most of the fingertips sustained a crushing injury and were reconstructed at the time of the injury. Soft tissue coverage was provided by palmar V-Y flaps in 6 cases, thenar flaps in 4, lateral V-Y flaps in 2, a Moberg flap in 1, and a cross-finger flap in 1. Split toenail bed grafts were used in 6 cases, full-thickness nail bed grafts from the amputated part in 6, and split nail bed grafts from the injured digit in 2. There was 1 partial graft loss and 1 partial flap loss. The remaining cases had completely successful grafts and good soft tissue healing. Subsequent nail growth and adherence were good in all but the 1 digit requiring secondary composite grafting.

Intra-abdominal desmoplastic small round cell tumor: immunohistochemical evidence for up-regulation of autocrine and paracrine growth factors

Desmoplastic small round cell tumors (DSRCT) are highly aggressive tumors typically involving the serosal surfaces of the peritoneum. Patients often present with abdominal pain, an abdominal mass, ascites or signs of intestinal obstruction. Cytogenetic and molecular studies have identified a characteristic t(11;22)(p13;q12) translocation within the tumor cells. The fused gene product apparently aligns the NH2-terminal domain (NTD) of the EWS gene to the zinc finger DNA-binding domain of the WT1 gene. This product could lead to loss of the tumor suppressor effect of the WT1 gene as well as to an increase in EWS driven expression of growth factors normally repressed by WT1. We investigated this latter possibility by performing immunohistochemical studies on formalin fixed tissue from 10 cases of DSRCT and five Wilms' tumors using antibodies to insulin-like growth factor (IGF)-II, the latency associated peptide of transforming growth factor (TGF)-beta1, platelet-derived growth factor (PDGF)-AB chain and PDGF-alpha receptor, respectively. In general, tumor cells were strongly positive for these growth factors in DSRCT, while stromal cells were negative for IGF-II and positive for the other growth factors in parallel with the tumor cells. Wilms' tumor cells were essentially negative for PDGF-AB chains, but positive for IGF-II, and the latency associated peptide of TGF-beta1 and variably positive for PDGF-alpha receptor. These findings support the proposed molecular mechanism of tumorigenesis for DSRCT and may help explain this tumor's poor prognosis.

MK-801 and male odours induce c-fos expression in the AOB of juvenile female mice

The odours of adult males, which accelerate the timing of puberty of female mice, activate c-fos in the accessory olfactory bulb (AOB). To test the hypothesis that NMDA receptors are involved in the male odour-induced increase in c-fos expression, we studied the effects of the non-competitive NMDA receptor agonist MK-801 on male odour-induced c-fos expression in the AOB of juvenile female mice. Surprisingly, MK-801 increased FOS-like immunoreactivity (FLI) within the AOB in the absence of male odour and had no effect on male odour-induced c-fos expression. We suggest that MK-801 increases AOB mitral cell activity by disinhibiting GABAergic granule cells, resulting in increased c-fos expression throughout the AOB.

Intra-abdominal desmoplastic small round cell tumor: immunohistochemical evidence for up-regulation of autocrine and paracrine growth factors

Desmoplastic small round cell tumors (DSRCT) are highly aggressive tumors typically involving the serosal surfaces of the peritoneum. Patients often present with abdominal pain, an abdominal mass, ascites or signs of intestinal obstruction. Cytogenetic and molecular studies have identified a characteristic t(11;22)(p13;q12) translocation within the tumor cells. The fused gene product apparently aligns the NH2-terminal domain (NTD) of the EWS gene to the zinc finger DNA-binding domain of the WT1 gene. This product could lead to loss of the tumor suppressor effect of the WT1 gene as well as to an increase in EWS driven expression of growth factors normally repressed by WT1. We investigated this latter possibility by performing immunohistochemical studies on formalin fixed tissue from 10 cases of DSRCT and five Wilms' tumors using-antibodies to insulin-like growth factor (IGF)-II, the latency associated peptide of transforming growth factor (TGF)-beta 1, platelet-derived growth factor (PDGF)-AB chain and PDGF-alpha receptor, respectively. In general, tumor cells were strongly positive for these growth factors in DSRCT, while stromal cells were negative for IGF-II and positive for the other growth factors in parallel with the tumor cells. Wilms' tumor cells were essentially negative for PDGF-AB chains, but positive for IGF-II, and the latency associated peptide of TGF-beta 1 and variably positive for PDGF-alpha receptor. These findings support the proposed molecular mechanism of tumorigenesis for DSRCT and may help explain this tumor's poor prognosis.

Cost-utility model comparing docetaxel and paclitaxel in advanced breast cancer patients

Relevant data from direct comparisons in clinical trials are not available for economic evaluations of docetaxel and paclitaxel in the management of metastatic breast cancer. A modified Markov model is used to estimate the incremental cost in US$ per quality-adjusted life-year (QALY) for docetaxel versus paclitaxel in managing metastatic breast cancer patients in the US. The model incorporates the latest available clinical trial data (response rates of 47.8% for docetaxel and 25% for paclitaxel, chemotherapy-specific toxicities, time to progression, and 1-year survival) from studies against other comparators. Medical care resources were estimated by US oncologists and costed using US data sources. Utility scores were obtained from 29 US oncology nurses. The base case and subsequent sensitivity analyses show that docetaxel management of advanced breast cancer is more costly per patient but yields higher health benefits than paclitaxel therapy. The cost per QALY gained by docetaxel is $8615, and ranges between $3943 and $9416 in sensitivity analyses. These results confirm those of an earlier model using preliminary data and compare favorably with other cost-utility results in this patient group.

Microsurgical replantation of the lip: a multi-institutional experience

Traumatic amputation of the lip is a rare yet devastating event affecting both form and function. Considering the available methods for reconstruction, replantation may offer a reasonable solution. We sought to characterize the variables associated with lip replantation and to assess the outcome in a retrospective review of 13 lip replantations performed in 12 institutions utilizing a form database and clinical and photographic analysis. Lip replantation was successful in all 13 patients; partial flap loss occurred in one patient owing to iatrogenic injury. Follow-up averaged 3.1 years. Average patient age at the time of injury was 21.1 years. There were six male and seven female patients. Injuries in two patients were the result of a human bite, the remaining injuries resulted from dog bites. One patient had significant associated injuries. Average length of hospital stay was 11.9 days. Ten patients suffered amputations of the upper lip, and three suffered amputations of the lower lip. Average defect size was 10.6 cm2. Operative time averaged 5.7 hours (range 2.5 to 12 hours). Warm ischemia time averaged 2.9 hours, and cold ischemia time averaged 2.7 hours. Donor and recipient veins were often scarce; all patients had at least one arterial anastomosis, whereas no vein was available in 7 of 13 patients; vein grafts were required in one patient. Leech therapy was employed in 11 of 13 patients. Anticoagulant therapy was administered in the majority of patients. Systemic heparin was utilized in 10 of 13 patients, low molecular weight dextran was used in 7 of 13 patients, and aspirin was given to 7 of 13 patients. One bleeding complication was incurred. An average of 6.2 units of packed red blood cells was administered to 12 of 13 patients (adjusted to 250 cc/unit). Antispasmodic therapy was employed in six of eight patients intraoperatively and in two of eight patients postoperatively. Intraoperative complications included difficulty identifying veins in 7 of 13 patients, arterial spasm in 1 of 13 patients, and vessel diameter < 0.5 mm in 4 patients. Postoperatively, one patient suffered vein thrombosis requiring anastomotic revision. Broad spectrum antibiotics were administered to all patients, and there were no infections. Nearly one-third (4 of 13) patients suffered prolonged edema lasting > 4 months. Color match of the replanted lip segment was rated excellent in all cases. Hypertrophic scarring occurred in 6 of 13 patients. A total of 12 revision procedures was performed in six patients. Interestingly, leech therapy resulted in permanent visible scarring as a result of the leech bite in 6 of 11 patients treated. Ten patients demonstrated active orbicularis muscle contraction in the replanted lip segment. Stomal continence was present in all lips. Sensibility return in the replanted lip segment was quite good with 12 of 13 patients demonstrating at least protective moving two-point sensibility (> or = 10 mm). Partial replant necrosis in one patient resulted in significant scar and contraction that compromised the aesthetic appearance. Overall, however, all patients were uniformly pleased with their final results. This clinical study is one of the largest of its kind on lip replantation. Although this represents a multi-institutional experience, the data are remarkably consistent. Re-establishment of venous outflow seems to be the most problematic technical challenge. By incorporating the adjuncts of anticoagulation, leech therapy, and antispasmodics, a successful outcome can be expected despite the paucity of vessels and small vessel size. The risks of blood transfusion, lengthy operative time, and hospital stay must be weighed against the functional benefits.

Lipid nanotubes as substrates for helical crystallization of macromolecules

A general approach for crystallization of proteins in a fast and simple manner would be of immense interest to biologists studying protein structure-function relationships. Here, we describe a method that we have developed for promoting the formation of helical arrays of proteins and macromolecular assemblies. Electron micrographs of the arrays are suitable for helical image analysis and three-dimensional reconstruction. We show that hydrated mixtures of the glycolipid galactosylceramide (GalCer) and derivatized lipids or charged lipids form unilamellar nanotubules. The tubules bind proteins in a specific manner via high affinity ligands on the polar head groups of the lipid or via electrostatic interactions. By doping the GalCer with a novel nickel-containing lipid, we have been able to form helical arrays of two histidine-tagged proteins. Similarly, doping with a biotinylated lipid allows crystallization of streptavidin. Finally, three proteins with affinity for positively or negatively charged lipid layers formed helical arrays on appropriately charged tubules. The generality of this method may allow a wide variety of proteins to be crystallized on lipid nanotubes under physiological conditions.

Assessment of intraneural oxygen tension and blood flow in a mobilized peripheral-nerve model

Extensive mobilization of injured peripheral nerves is often required to allow a tension-free repair. The purpose of this study was to determine the effect of surgical mobilization and division on intraneural blood flow and oxygen tension in a rat sciatic nerve model. The right and left sciatic nerves were exposed in male Lewis rats Four experimental groups were studied: 1) nerve in situ/intact (n=7); 2) nerve mobilized and intact (n=7); 3) nerve in situ/divided (n=7); and 4) nerve mobilized and divided (n=7). Intraneural oxygen tension and blood flow were measured postoperatively. Mean oxygen tension (mmHg) in mobilized/intact nerves (17.47+/-4.79) was significantly lower than in in situ/intact nerves (38.32+/-5.16) [p < 0.05]. Mean oxygen tension in mobilized/divided nerves (3.10+/-1.25) was significantly lower than in in situ/divided nerves (30.30+/-6.36) [p < 0.005]. Laser Doppler flow (ml/min/100 g) in mobilized divided nerves (11.31+/-1.81) was significantly lower than in in situ/divided nerves (25.60+/-3.31) [p < 0.05]. Laser Doppler flow in mobilized/intact nerves was not statistically significantly different from in situ/intact nerves. Mobilization of the extrinsic blood supply was shown to significantly lower intraneura) oxygen tension and laser Doppler flow in mobilized intact and divided rat peripheral nerves.

Health and economic outcomes modeling practices: a suggested framework

In the field of outcomes research, modeling is increasingly being used to assess costs and outcomes associated with healthcare interventions. However, there is little standardization with regard to modeling practices, and the quality and usefulness of economic and health outcomes models may vary. We propose the following set of recommendations for good modeling practices to be used in both the development and review of models. These recommendations are divided into three sections: criteria to be addressed before model development or initial review; criteria used during model development or evaluation; and criteria used following model development. These recommendations also include examples regarding different modeling techniques and practices as well as a checklist (see appendix) to assess model correspondence with the recommendations. We hope that the use of good practice recommendations for modeling will not only improve the development and review of models but also lead to greater acceptance of this methodology.

In vivo electrophysiological investigations into the role of histamine in the dentate gyrus of the rat

Drugs acting at the three known classes of histamine receptors were injected intracerebroventricularly into the rat. The effects of these drugs upon synaptic potentials recorded from the dentate gyrus of the freely-moving rat were determined. Population spikes and field excitatory postsynaptic potentials were recorded from the granule cell layer of the dentate gyrus following stimulation of the perforant path. Drugs, dissolved in 0.9% NaCl were applied into the lateral cerebral ventricle in a volume of 5 microl over a period of 6 min. The histamine H1 receptor antagonist mepyramine (0.4 or 0.8 microg) had no significant effect on population spikes or field excitatory postsynaptic potentials. In contrast the H2 receptor antagonist cimetidine (3.25, 6.5 or 13 microg) showed a biphasic effect. At the lower doses (3.25 or 6.5 microg) a small (15%) depression of the field excitatory postsynaptic potentials and population spikes was observed beginning about 1 h following the infusion. At the highest dose tested (13 microg) a marked increase of the population spike was observed beginning immediately following the infusion and lasting for 90 min. Application of the H3 receptor agonist R-alpha-methylhistamine (0.2 microg) depressed the field excitatory postsynaptic potentials (15% at 4 h post-injection) and even more strongly the population spike (50%). Surprisingly, at higher doses (0.4 and 0.8 microg) no effect was seen. The H3 receptor antagonist thioperamide (0.41 and 0.82 microg) did not cause an increase in synaptic potentials but rather at the highest dose a small depression occurred at later time points (2-4 h following the infusion). At the lower dose (0.41 microg) thioperamide blocked the effect of R-alpha-methylhistamine (0.2 microg). These results show that the histaminergic system modulates information flow through the dentate gyrus in a complex manner involving both histamine H2 and H1 receptors.

A cost-effectiveness clinical decision analysis model for schizophrenia

A model was developed to estimate the medical costs and effectiveness outcomes of three antipsychotic treatments (olanzapine, haloperidol, and risperidone) for patients with schizophrenia. A decision analytic Markov model was used to determine the cost-effectiveness of treatments and outcomes that patients treated for schizophrenia may experience over a 5-year period. Model parameter estimates were based on clinical trial data, published medical literature, and, when needed, clinician judgment. Direct medical costs were incorporated into the model, and outcomes were expressed by using three effectiveness indicators: the Brief Psychiatric Rating Scale, quality-adjusted life years, and lack of relapse. Over a 5-year period, patients on olanzapine had an additional 6.8 months in a disability-free health state based on Brief Psychiatric Rating Scale scores and more than 2 additional months in a disability-free health state based on quality-adjusted life years, and they experienced 13% fewer relapses compared with patients on haloperidol. The estimated 5-year medical cost associated with olanzapine therapy was $1,539 less than that for haloperidol therapy. Compared with risperidone therapy, olanzapine therapy cost $1,875 less over a 5-year period. Patients on olanzapine had approximately 1.6 weeks more time in a disability-free health state (based on Brief Psychiatric Rating Scale scores) and 2% fewer relapses compared with patients on risperidone. Sensitivity analyses indicated the model was sensitive to changes in drug costs and shortened hospital stay. Compared with both haloperidol and risperidone therapy, olanzapine therapy was less expensive and provided superior effectiveness outcomes even with conservative values for key parameters such as relapse and discontinuation rates.

Sphingolipid organization in biomembranes: what physical studies of model membranes reveal

Recent cell biological studies suggest that sphingolipids and cholesterol may cluster in biomembranes to form raft-like microdomains. Such lipid domains are postulated to function as platforms involved in the lateral sorting of certain proteins during their trafficking within cells as well as during signal transduction events. Here, the physical interactions that occur between cholesterol and sphingolipids in model membrane systems are discussed within the context of microdomain formation. A model is presented in which the role of cholesterol is refined compared to earlier models.

Acyl chain-length asymmetry alters the interfacial elastic interactions of phosphatidylcholines

Phosphatidylcholines (PCs) with stearoyl (18:0) sn-1 chains and variable-length, saturated sn-2 acyl chains were synthesized and investigated using a Langmuir-type film balance. Surface pressure was monitored as a function of lipid molecular area at various constant temperatures between 10 degrees C and 30 degrees C. Over this temperature range, 18:0-10:0 PC displayed only liquid-expanded behavior. In contrast, di-14:0 PC displayed liquid-expanded behavior at 24 degrees C and 30 degrees C, but two-dimensional phase transitions were evident at 20 degrees C, 15 degrees C, and 10 degrees C. The average molecular area of 18:0-10:0 PC was larger than that of liquid-expanded di-14:0 PC at equivalent surface pressures, and the shapes of their liquid expanded isotherms were somewhat dissimilar. Analysis of the elastic moduli of area compressibility (Cs(-1)) as a function of molecular area revealed shallower slopes in the semilog plots of 18:0-10:0 PC compared to di-14:0 PC. At membrane-like surface pressures (e.g., 30 mN/m), 18:0-10:0 PC was 20-25% more elastic (in an in-plane sense) than di-14:0 PC. Other PCs with varying degrees of chain-length asymmetry (18:0-8:0 PC, 18:0-12:0 PC, 18:0-14:0 PC, 18:0-16:0 PC) were also investigated to determine whether the higher in-plane elasticity of fluid-phase 18:0-10:0 PC is a common feature of PCs with asymmetrical chain lengths. Two-dimensional phase transitions in 18:0-14:0 PC and 18:0-16:0 PC prevented meaningful comparison with other fluid-phase PCs at 30 mN/m. However, the Cs(-1) values for fluid-phase 18:0-8:0 PC and 18:0-12:0 PC were similar to that of 18:0-10:0 PC (85-90 mN/m). These values showed chain-length asymmetrical PCs to have 20-25% greater in-plane elasticity than fluid-phase PCs with mono- or diunsaturated acyl chains.

Menetrier's disease presenting with iron deficiency anemia

Menetrier's disease (MD) or polyadenomes en nappe is a form of hypertrophic gastropathy occurring primarily in middle-aged males. Patients generally present clinically with dyspepsia and, on occasion, with hypoproteinemic edema and anemia. The latter feature, when combined with the radiographic appearance of the stomach in MD, can lend to confusion with carcinoma and malignant lymphoma. To illustrate this diagnostic problem, a case is reported of a 41-year-old female who initially presented to her family physician with symptoms of easy fatigue and dyspnea on exertion and signs of pallor and ankle edema. Pertinent laboratory findings included a hemoglobin of 2.8 g/dL, hematocrit of 10.3 percent, mean corpuscular volume of 63.4 mu 3, a serum albumin of 2.7 g/dL, and heme positive stools. Endoscopic examination revealed a circumferential polypoid mass involving the cardia and fundus of the stomach with relative sparing of the antrum. A CT scan of the abdomen and pelvis showed a large mass in the stomach which the radiologists and gastroenterologists believed probably represented a lymphoma or gastric carcinoma. A total gastrectomy specimen exhibited features of MD. Routine bright-field microscopy and immunohistochemical reactivity for transforming growth factor-alpha confirmed the diagnosis of MD. Moreover, ulceration of the tips of some of the hypertrophied gastric folds provided an explantation for the iron deficiency anemia. Awareness that MD may present with anemia will help in the differential diagnosis with lymphoma and carcinoma.

Long-term increase of hippocampal excitability by histamine and cyclic AMP

The action of histamine (HA) on rat hippocampal CA1 pyramidal cells in vitro was investigated in slices perfused with solution containing 0.2 mM Ca2+/4.0 mM Mg2+. Extracellular recordings of the spontaneous discharges occurring under these conditions revealed that HA caused a long-lasting increase in cell firing. The HA-effects were dose-dependent, in that low concentrations of HA (0.1-0.5 microM) exhibited an initial transient depression of cell firing and practically no long-lasting action, whereas higher concentrations of HA (1-10 microM) exerted strong, non-declining increases. The H1-receptor antagonist mepyramine (1 microM) blocked the initial depression of firing and attenuated the long-lasting HA-mediated excitation. Pure H1-receptor activation, tested with the H1-receptor agonist 2-(3-fluorphenyl)histamine (1-10 microM) depressed cell firing, similar to the low dose effects of HA. HA-induced excitations were prevented by the H2-receptor antagonist cimetidine (10-50 microM), and mimicked by the very potent H2-receptor agonist impromidine (1 or 3 microM) which was, however, less effective compared to equal concentrations of HA. H3-receptor activation by R-alpha-methylhistamine had no significant effect on cell firing. Thus, histamine H1 and H2 receptors seem to cooperate in producing this long-lasting augmentation of excitability. 8-Bromo-cyclic AMP monophosphate (8-Br-cAMP, 50-100 microM) mimicked the long-term excitation, whereas the adenylyl-cyclase inhibitor 9-tetrahydro-2-furyladenine (THFA, 100-500 microM) or the PKA-inhibitor Rp-adenosine-3'5'-cyclic monophosphate (Rp-cAMPS, 10 microM) blocked it, indicating that the HA-mediated increase of excitability in the hippocampus is dependent on the adenylate cyclase/PKA-signal transduction cascade. DL-2-Amino-5-phosphonopentanoic acid (APV, 50 microM) significantly attenuated the magnitude of the HA-induced enhancement, indicating an NMDA receptor-dependent component. Other biogenic amines, acting through receptors positively coupled to adenylyl cyclase, elicited similar responses as HA, indicating common mechanisms by which these substances modulate excitability in CA1 pyramidal cells.