Phase I trial of 5-fluorouracil,leucovorin, and cisplatin in combination

Summary The ongoing evaluation of combination chemotherapy with 5-fluorouracil (5-FU) and cisplatin in several tumors prompted a phase I clinical trial of cisplatin with 5-FU modulated by leucovorin. A total of 26 patients were treated with varying doses of 5-FU by continuous i.v. infusion for 5 days; 200 mg/m² leucovorin was given by daily bolus injection for 5 days; and 20 mg/m² cisplatin was infused over 2 h on each day of treatment. Courses were repeated every 21–28 days. The starting dose of 5-FU was 300 mg/m². Poor-risk patients (extensive prior radiation, performance status of 2 or worse) did not tolerate the initial dose; the maximum tolerated dose of 5-FU in this group was 200 mg/m² daily. Good-risk patients tolerated 300 mg/m², but a majority had excessive toxicity at higher doses. The dose-limiting toxicity was gastrointestinal (mucositis/diarrhea) and/or myelosuppression; additional side effects included were nausea and vomiting (grade 2) and ataxia (one patient). Among 13 patients with colorectal cancer, 4 partial responses were observed. The marked reduction in the tolerable dose of 5-FU occasioned by the addition of modulating doses of leucovorin is noteworthy. The response observed support further investigation of this regimen in phase II trials.     

Evidence that implementation intentions reduce self-harm in the community

Objectives

Implementation intentions are ‘IF-THEN’ plans that encourage goal-intended behaviour. This study was designed to test whether an intervention encouraging the formation of implementation intentions can reduce self-harm in the community.

Design

A randomized controlled design was used.

Methods

At pre-intervention, outcome variables (self-harm in both specified and unspecified critical situations and suicidality) and potential moderators of implementation intentions (goal intention, mental imagery, and exposure to self-harm) were measured using self-report questionnaires. The participants (N = 469, aged 18–66 years, 86.4% female, 6.8% male and 6.7% other) were then randomized to either an experimental (implementation intention) or control task. At three-months post-intervention, self-report questionnaires were used again to measure the outcome variables.

Results

There were no overall differences between the conditions at post-intervention. However, goal intention and mental imagery, but not exposure to self-harm, moderated the effects of condition on self-harm in specified critical situations. At high (mean + 1SD) levels of both goal intention and mental imagery, the experimental condition reported self-harming less frequently in the situations specified in their implementation intentions.

Conclusions

Implementation intentions therefore represent a useful intervention for reducing self-harm in specified critical situations for people in the community who wish to avoid self-harm and those who frequently experience self-harm and suicide related mental imagery.     

Decorin and suramin inhibit ocular fibroblast collagen production

Background: The process of ocular wound healing with respect to glaucomatous filtering procedures is of current interest. Delaying this response in patients could possibly lead to more favorable surgical results. So far, only highly toxic antimetabolites have come into frequent clinical use. The possible efficacy of other groups of substances such as growth factor inhibitors has not yet been examined in vitro. Methods: We exposed Tenon's capsule fibroblasts in tissue culture to various concentrations of decorin and suramin. The dose responses of type I and type III collagen to these inhibitors were measured using an ELISA-type dot blot assay. Total cellular protein production was assayed by measuring the incorporation of tritiated leucine. Results: At a concentration of 10 g/ml, suramin reduced the collagen production by more than 80%. Decorin, at a concentration of 100 g/ml, reduced type I collagen production by about 50% while type III collagen was reduced by 80%. At these concentrations, the total cellular protein production was not inhibited. Conclusions: Both suramin and decorin, which specifically inhibit the action of growth factors on target cells, reduce the production of collagen synthesis by Tenon's capsule fibroblasts. This is a specific effect, because total protein production is not influenced. This sets these substances apart from antimetabolites. Decorin and suramin may have clinical relevance in that they appear to interfere with ocular wound healing more specifically than the substances so far frequently used.     

Characterization of the prostanoid receptor(s) on human blood monocytes at which prostaglandin E2 inhibits lipopolysaccharide-induced tumour necrosis factor-α generation

1. The prostanoid receptor(s) that mediates inhibition of bacterial lipopolysaccharide (LPS)-induced tumour necrosis factor-α (TNFα) generation from human peripheral blood monocytes was classified by use of naturally occurring and synthetic prostanoid agonists and antagonists.
2. In human monocytes that were adherent to plastic, neither prostaglandin D₂ (PGD₂), prostaglandin E₂ (PGE₂), prostaglandin F_2α (PGF_2α) nor the stable prostacyclin and thromboxane mimetics, cicaprost and U-46619, respectively, promoted the elaboration of TNFα-like immunoreactivity, as assessed with a specific ELISA, indicating the absence of excitatory prostanoid receptors on these cells.
3. Exposure of human monocytes to LPS (3 ng ml⁻¹, ∼ EC₈₄) resulted in a time-dependent elaboration of TNFα which was suppressed in cells pretreated with prostaglandin E₁ (PGE₁), PGE₂ and cicaprost. This effect was concentration-dependent with mean pIC₅₀ values of 7.14, 7.34 and 8.00 for PGE₁, PGE₂ and cicaprost, respectively. PGD₂, PGF_2α and U-46619 failed to inhibit the generation of TNFα at concentrations up to 10 μM.
4. With respect to PGE₂, the EP-receptor agonists, 16,16-dimethyl PGE₂ (non-selective), misoprostol (EP₂/EP₃-selective), 11-deoxy PGE₁ (EP₂-selective) and butaprost (EP₂-selective) were essentially full agonists as inhibitors of LPS-induced TNFα generation with mean pIC₅₀ values of 6.21, 6.02, 5.67 and 5.59, respectively. In contrast to the results obtained with butaprost and 11-deoxy PGE₁, another EP₂-selective agonist, AH 13205, inhibited TNFα generation by only 21% at the highest concentration (10 μM) examined. EP-receptor agonists which have selectivity for the EP₁- (17-phenyl-ω-trinor PGE₂) and EP₃-receptor (MB 28,767, sulprostone) were inactive or only weakly active as inhibitors of TNFα generation.
5. Pretreatment of human monocytes with the TP/EP₄-receptor antagonist, AH 23848B, at 10, 30 and 100 μM suppressed LPS-induced TNFα generation by 10%, 28% and 77%, respectively, but failed to shift significantly the location of the PGE₂ concentration-response curves.
6. Given that AH 13205 was a poor inhibitor of TNFα generation, studies were performed to determine if it was a partial agonist and whether it could antagonize the inhibitory effect of PGE₂. Pretreatment of human monocytes with 10 and 30 μM AH 13205 inhibited the generation of TNFα by 31% and 53%, respectively, but failed to shift significantly the location of the PGE₂ concentration-response curves at either concentration examined.
7. Since PGD₂ and 17-phenyl-ω-trinor PGE₂ (EP₁-agonist) did not suppress TNFα generation, the EP₁/EP₂/DP-receptor antagonist, AH 6809, was employed to assess if EP₂-receptors mediated the inhibitory effect of PGE₂. Pretreatment of human monocytes with 10 μM AH 6809 did not affect LPS-induced TNFα generation but produced a parallel 3.5 fold rightwards shift of the PGE₂ concentration-response curve.
8. Collectively, these data suggest that human peripheral blood monocytes express at least two distinct populations of inhibitory prostanoid receptors that mediate inhibition of LPS-induced TNFα generation. One of these probably represents IP receptors based upon the selectivity of cicaprost for this subtype. The other population has the pharmacology of EP-receptors, but the rank order of potency for a range of synthetic EP-receptor agonists was inconsistent with an interaction with any of the currently defined subtypes. Given the pharmacological behaviour of butaprost, AH 6809 and AH 23848B in these cells, we propose that multiple (EP₂- and/or EP₄- and/or IP) or novel EP-receptors mediate the inhibitory effect of PGE₂ on TNFα generation.

     

Hypoglycaemic effects of the novel antidiabetic agent repaglinide in rats and dogs

1. Repaglinide, a novel compound with a nonsulphonylurea structure, is currently being clinically tested as a therapeutic agent. In the present study, the hypoglycaemic effects of repaglinide in rats and dogs were investigated.
2. Whereas the R-enantiomer, AG-EE 624 ZW, showed only weak hypoglycaemic activity, the S-enantiomer, repaglinide, turned out to be a potent hypoglycaemic compound in rats after oral as well as after intravenous administration. Only 50% of the dose of repaglinide was needed to be equieffective with the racemic mixture AG-EE 388 ZW. The corresponding ED₅₀ values calculated for the effects after 120 min p.a. (intravenous administration) were 3.4 μg kg⁻¹ (repaglinide) and 6 μg kg⁻¹ (AG-EE 388 ZW).
3. When compared to glimepiride or glibenclamide, repaglinide displayed a 18 to 25 times higher potency in fasted rats. The ED₅₀ values calculated for the effects after 120 min p.a. (oral administration) were 10 μg kg⁻¹ (repaglinide), 182 μg kg⁻¹ (glimepiride) and 255 μg kg⁻¹ (glibenclamide).
4. In glucose loaded rats (0.5, 1.0, 2.0 and 3.0 g kg⁻¹ glucose, p.o.) repaglinide exerted a very strong antihyperglycaemic activity which was even more pronounced than under normoglycaemic conditions. So for a reduction in blood glucose of 1 mmol l⁻¹, 10.3, 9.3, 7.0 8.4 and 7.2 μg kg⁻¹ repaglinide were needed after glucose loads of 0.0, 0.5, 1.0, 2.0 and 3.0 g kg⁻¹, respectively.
5. In beagle dogs repaglinide again showed a pronounced hypoglycaemic effect (ED₅₀ 28.3 μg kg⁻¹) which lasted for up to 24 h. However, insulin levels were only transiently increased.
6. The in vivo data presented are well supported by recently published in vitro findings. From its activity profile, repaglinide appears to be a promising new therapeutic agent.

     

Attenuation of the cutaneous blood flow response during combined exercise and heat stress

Skin blood flow (SkBF) was measured in six male subjects using laser-Doppler velocimetry, with zero-gradient auditory canal temperature (T_ac) used as an index of body core temperature (T_c). Subjects performed incremental, upright cycling commencing at 40% peak power ( _peak: 10 min), increasing every 4 min by 5 % _peak thereafter. Trials were conducted in hot (ambient temperature (T_a) 36.7 ±0.2°C, relative humidity (rh) 46.1 ±3.2%; _peak ±S.D.), and neutral environments (T_a 19.6 ±0.3°C, rh 50.2 ±1.4%). SkBF increased with T_ac in all subjects. Attenuation of SkBF occurred at the same T_ac, relative SkBF and cardiac frequency (f _c) between environments, but at a lower exercise intensity (40.8 ±0.8% versus 55.8 ±3.0% _peak) in the hot environment (p<0.05). Data indicate that T_c thresholds for SkBF attenuation may exist. However, it is suggested that attenuation thresholds coincided with a reduced central blood volume, which may occur at a critical level of cutaneous blood pooling.     

Analysis of a tension/compression skeletal system: Possible strain-specific differences in the hierarchical organization of bone

Background: Examination of a simple skeletal cantilevered beam-like bone (artiodactyl calcaneus) suggests that regional differences in strain magnitude and mode (tension vs. compression) reflect regional adaptation in the structural/material organization of bone. The artiodactyl (e.g., sheep and deer) calcaneus has a predominant loading condition typified by the unambiguous presence of prevailing compressive and tensile strains on opposite cortices. Bone habitually loaded in bending may accommodate regional disparities in loading conditions through modifications of various aspects of its organization. These include overall bone build (gross size and shape), cross-sectional shape, cortical thickness, and mineral content. Methods & Results: Cross-sections taken along the calcaneal body exhibited cranial-caudal elongation with the compression (cranial) cortex thicker than the tension cortex (P < 0.01). Mineral content (ash fraction) was significantly greater in the compression cortex (P < 0.01), averaging 6.6% greater than in the tension cortex. Strong positive correlations were found between mineral content and section location in both the tension (r² = 0.955) and compression (r² = 0.812) cortices. These correlations may reflect functional adaptations to the linear increases in stress that are known to occur in the distal-to-proximal direction in simple, unidirectionally loaded cantilevered beams. According to engineering principles, the roughly triangular transverse cross-sectional geometries and thicker compression cortex are features consistent with a short cantilevered structure designed to resist unidirectional bending. Conclusions: Known differences in mechanical properties of bone in tension vs. compression suggest that these regional differences in cortical thickness and mineralization may be related to differences in strain mode. These structural/material dissimilarities, however, may be related to regional variations in strain magnitude, since bending and axially directed stresses in a simple cantilevered structure produce greater strain magnitudes in the compression domain. It is possible that the superimposed habitual strain magnitudes enhance strain-mode-specific adaptive responses. We hypothesize that these structural/material differences reflect the capacity of bone to process local information and produce a regionally heterogeneous organization that is appropriate for prevailing loading conditions. © 1994 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public dotmain in the United states of America

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Admission,recruitment, and retention

As the country strives to produce larger numbers of generalist physicians, considerable controversy has arisen over whether or not generalist applicants can be identified, recruited, and influenced to keep a generalist-oriented commitment throughout medical training. The authors present new and existing data to show that: 1) preadmission (BA/MD or post-baccalaureate) programs can help to identify generalist-oriented students; 2) characteristics determinedat admission to medical school are predictive of future generalist career choice; 3) current inpatient-oriented training programs strongly push students away from a primary care career; 4) women are more likely than men to choose generalist careers, primarily because of those careers’ interpersonal orientation; and 5) residency training programs are able to select applicants likely to become generalists. Therefore, to produce more generalists, attempts should be made to encourage generalist-oriented students to enter medical schools and to revise curricula to focus on outpatient settings in which students can establish effective and satisfying relationships with patients. These strategies are most likely to be successful if enacted within the context of governmental and medical school-based changes that allow for more reimbursement and respect for the generalist disciplines.     

Brain activation associated with visual motion studied by functional magnetic resonance imaging in humans

Localized brain activation in response to moving visual stimuli was studied by functional magnetic resonance imaging (fMRI). Stimuli were 100 small white dots randomly arranged on a visual display. During the Motion condition, the dots moved along random, noncoherent linear trajectories at different velocities. During the Blink condition, the dots remained stationary but blinked on and off every 500 ms. The Motion and Blink conditions continuously alternated with 10 cycles per run and 6–8 runs per experiment. In half of the runs, the starting stimulus condition was Motion, while in the remaining runs it was Blink. A series of 128 gradient echo echoplanar images were acquired from 5–7 slices during each run using a 1.5 T GE Signa with an Advanced NMR echoplanar subsystem. The time series for each voxel were analyzed in the frequency domain. Voxels which demonstrated a significant spectral peak at the alternation frequency and whose phase changed in response to stimulus order were considered activated. These activated voxels were displayed upon high resolution anatomical images to determine the sites of activation and were also transformed into the coordinates of Talairach and Tournoux ([1988] Co-planar Stereotaxic Atlas of the Human Brain, New York: Thieme) for comparison to prior neuroimaging studies. Seven of ten subjects showed clusters of activation bilaterally at the junction of the temporal and occipital lobes (area 37) in response to moving stimuli. Most activated voxels were located within or adjacent to a region designated the parietal-temporal-occipital fossa, or PTOF. Five subjects also showed activation to moving stimuli in midline occipital cortex. The activated voxels in midline cortex had a significantly shorter phase delay in their MR signal change relative to voxels in PTOF. © 1995 Wiley-Liss, Inc. 1

1 This article is a US Government work and, as such, is in the public domain in the United States of America

     

Is hypoxic pulmonary vasoconstriction important during single lung ventilation in the lateral decubitus position?

Hypoxic pulmonary vasoconstriction (HPV) has not been demonstrated in human single lung anaesthesia in the lateral decubitus position (LDP). The purpose of this study was to determine whether (1) HPV occurs in the non-dependent, nonventilated lung, and (2) if the infusion of sodium nitroprusside (SNP) inhibits HPV During intravenous anaesthesia the tracheas of seven patients were intubated with double lumen endotracheal tubes. Standard monitors plus radial and pulmonary arterial catheters were placed. Patients were positioned in the LDP and haemodynamic and gas exchange data were recorded for each of three stages; I: two-lung ventilation, II: single, dependent lung ventilation (1LV) and III: 1LV with infusion of SNP. In stage II the PaO₂ decreased from 531 ± 42 mmHg to 285 ± 42 mmHg (P < 0.05) and Qs/Qt increased from 12.3 ± 2.7 to 29.0 ± 6.3% (P < 0.05). With SNP infusion there was a 30% increase in cardiac index (CI) (P < 0.05). The SNP infusion was not associated with changes in Qs/ Qt or PaO₂. This model demonstrates changes in Qs/ Qt and PaO₂ associated with single-lung ventilation in ASA I and II patients in the LDP but we were unable to demonstrate inhibition of HPV by SNP.