Regorafenib (BAY 73-4506) in advanced colorectal cancer: a phase I study

BACKGROUND

In a phase I dose-escalation study, regorafenib demonstrated tolerability and antitumour activity in solid tumour patients. The study was expanded to focus on patients with metastatic colorectal cancer (CRC).

METHODS

Patients received oral regorafenib 60-220 mg daily (160 mg daily in the extension cohort) in cycles of 21 days on, 7 days off treatment. Assessments included toxicity, response, pharmacokinetics and pharmacodynamics.

RESULTS

Thirty-eight patients with heavily pretreated CRC (median 4 prior lines of therapy, range 0-7) were enrolled in the dose-escalation and extension phases; 26 patients received regorafenib 160 mg daily. Median treatment duration was 53 days (range 7-280 days). The most common treatment-related toxicities included hand-foot skin reaction, fatigue, voice change and rash. Twenty-seven patients were evaluable for response: 1 achieved partial response and 19 had stable disease. Median progression-free survival was 107 days (95% CI, 66-161). At steady state, regorafenib and its active metabolites had similar systemic exposure. Pharmacodynamic assessment indicated decreased tumour perfusion in most patients.

CONCLUSION

Regorafenib showed tolerability and antitumour activity in patients with metastatic CRC. This expanded-cohort phase I study provided the foundation for further clinical trials of regorafenib in this patient population.

Phase I evaluation of telatinib, a VEGF receptor tyrosine kinase inhibitor, in combination with bevacizumab in subjects with advanced solid tumors

BACKGROUND

Blocking both receptor and ligand of the vascular endothelial growth factor (receptor) VEGF(R) pathway might be feasible and increase antitumor activity. This phase I study investigated telatinib, an oral tyrosine kinase inhibitor targeting VEGFR-2, combined with bevacizumab, in adults with solid tumors.

PATIENTS AND METHODS

Twenty-six patients were treated in successive cohorts with telatinib (twice-daily continuously, 450-900 mg) or bevacizumab (bi-weekly, starting dose 5 mg/kg). Safety, pharmacokinetics, endothelial (progenitor) cell (E(P)C)/growth factor kinetics and efficacy were assessed.

RESULTS

Most frequent adverse events were pain, nausea, voice changes and fatigue. Five dose-limiting toxicities (DLTs) occurred: hypertension (cohort I and II), bowel perforation, lipase increase and atrial flutter (cohort III). Cumulative toxicity resulted in a bevacizumab dose reduction to 1 mg/kg (cohort III). Due to three DLTs (n = 14), this cohort represented the best-tolerated dose level. Bevacizumab effectively neutralized plasma VEGF even at 1 mg/kg. Twelve patients had stable disease (clinical benefit 46%). EPC and SDF-1α levels increased during monotherapy telatinib.

CONCLUSIONS

Telatinib (450 mg b.i.d.) combined with bevacizumab (1 mg/kg bi-weekly) shows antitumor activity, but accumulating constitutional toxicity impedes long-term treatment of patients. Therefore, this combination will not be pursued in a phase II setting.

Phase I study of BAY 73–4506, an inhibitor of oncogenic and angiogenic kinases, in patients with advanced refractory colorectal carcinoma (CRC)

3560^

Background: BAY 73–4506 is a potent inhibitor of the receptor tyrosine kinases (VEGFR, KIT, RET, FGFR and PDGFR) and serine/threonine kinases (RAF and p38MAPK). In in-vivo models, BAY 73–4506 has demonstrated a broad spectrum of antitumor activity. Methods: This phase I study investigated the safety and pharmacokinetic (PK)/pharmacodynamic (PD) profiles of BAY 73–4506, given orally in repeating cycles of 21 days on/7 days off, in patients with refractory CRC. PK assessments were performed on days 1 and 21 of cycle 1. PD markers - including DCE-MRI and plasma levels of VEGF/soluble VEGFR-2 - were assessed at each cycle. Tumor response was evaluated per RECIST. Results: 38 patients with actively progressing CRC were treated with BAY 73–4506 at doses of 60 mg (n = 1), 120 mg (n = 4), 160 mg (n = 26), and 220 mg (n = 7) once daily. Median treatment duration was 56.5 days (range, 7–219 days). Drug-related adverse events (AEs) of all grades reported in >20% of patients were hand-foot skin reaction (HFSR) (61%; CTC 3–4, 32%), fatigue (45%; CTC 3, 11%), hoarseness (24%; CTC 3, 3%), mucositis (24%), diarrhea (24%; CTC 3, 3%), anorexia (24%), and hypertension (21%; CTC 3, 13%). Treatment-related AEs leading to dose reduction, interruption, or discontinuation (in ≥2 of patients) were HFSR (26%), fatigue (18%), thrombopenia (8%), and hypertension (5%). BAY 73–4506 showed a dose-dependent increase in exposure up to 160 mg, at which point a plateau was reached. One of 27 evaluable patients achieved a partial response (4%), 15 had stable disease (SD) at least 7 weeks after the start of treatment (55%), and 6 had SD for more than 23 weeks (22%). Patients had extensive previous antitumor treatment, including bevacizumab (44%) and cetuximab (59%). Decreases in soluble VEGFR-2 levels and iAUC60s of Gd-DTPA by DCE-MRI demonstrated that BAY 73–4506 was active on biologically relevant markers. Conclusions: BAY 73–4506 dosing at 160 mg daily, using a treatment schedule of 21 days on/7 days off was feasible in patients with advanced refractory CRC. Promising clinical activity was shown, with a disease control rate (PR+SD) of 59% in evaluable patients. Mutational analysis of selected genes (KRAS, BRAF) is ongoing.

[Table: see text]

ASCO Conflict of Interest Policy and Exceptions

In compliance with the guidelines established by the ASCO Conflict of Interest Policy (J Clin Oncol. 2006 Jan 20;24[3]:519–521) and the Accreditation Council for Continuing Medical Education (ACCME), ASCO strives to promote balance, independence, objectivity, and scientific rigor through disclosure of financial and other interests, and identification and management of potential conflicts. According to the ASCO Conflict of Interest Policy, the following financial and other relationships must be disclosed: employment or leadership position, consultant or advisory role, stock ownership, honoraria, research funding, expert testimony, and other remuneration (J Clin Oncol. 2006 Jan 20;24[3]:520). The ASCO Conflict of Interest Policy disclosure requirements apply to all authors who submit abstracts to the Annual Meeting.

For clinical trials that began accrual on or after April 29, 2004, ASCO's Policy places some restrictions on the financial relationships of principal investigators (J Clin Oncol. 2006 Jan 20;24[3]:521). If a principal investigator holds any restricted relationships, his or her abstract will be ineligible for placement in the 2009 Annual Meeting unless the ASCO Ethics Committee grants an exception. Among the circumstances that might justify an exception are that the principal investigator (1) is a widely acknowledged expert in a particular therapeutic area; (2) is the inventor of a unique technology or treatment being evaluated in the clinical trial; or (3) is involved in international clinical oncology research and has acted consistently with recognized international standards of ethics in the conduct of clinical research. NIH-sponsored trials are exempt from the Policy restrictions. Abstracts for which authors requested and have been granted an exception in accordance with ASCO's Policy are designated with a caret symbol (^) in the Annual Meeting Proceedings.

For more information about the ASCO Conflict of Interest Policy and the exceptions process, please visit www.asco.org/conflictofinterest .

Treatment with azathioprine and cyclic methylprednisolone has little or no effect on bioactivity in anti-interferon beta antibody-positive patients with multiple sclerosis

Background

It is unknown whether immunosuppression of patients who have developed interferon-β (IFN-β) neutralizing antibodies (NAbs) hastens disappearance of NAbs in the blood.

Objective

We wanted to test whether immunosuppression with cyclic methylprednisolone (MP) in combination with azathioprine (AZA) for 6 months accelerates recovery of IFN-β bioactivity in patients with multiple sclerosis (MS) with abolished in-vivo myxovirus resistance protein A (MxA) mRNA response to IFN-β.

Methods

We included 13 patients with MS with NAbs and a low IFN-β bioavailability detected by the MxA-mRNA response in a descriptive, non-randomized trial. Another 14 NAb-positive patients with a low MxA-mRNA response served as controls. The primary outcome was the fraction of patients who regained an MxA-mRNA response to IFN-β. NAbs were measured by means of a clinically validated cytopathic effect assay and a new reporter gene assay. The in-vivo MxA-mRNA response was measured by real-time polymerase chain reaction.

Results

A total of 11 patients in the treatment group completed the trial. In all, two of these 11 patients regained an in-vivo MxA-mRNA response as compared to one of 14 patients in the control group.

Conclusion

Treatment with AZA and cyclic MP for 6 months has little or no effect on IFN-β bioactivity in NAb-positive patients with MS.

Phase I study of BAY 73–4506, a multikinase inhibitor, administered for 21 days on/7 days off in patients with advanced solid tumors

3593

Background: BAY 73–4506 is a multikinase inhibitor targeting both the tumor and its vasculature. BAY 73–4506 inhibits VEGFR-2 and -3, and tumor cell signaling kinases (RET, KIT, PDGFR, and Raf). This drug shows potent, oral activity in a wide variety of preclinical xenograft models. Methods: This phase I dose-escalation trial investigated the safety, pharmacokinetic (PK), and pharmacodynamic (PD) profile of BAY 73–4506 given orally in 21 days on/7 days off cycles, until discontinuation due to toxicity or tumor progression. PK was assessed on days 1 and 21 of cycle 1. PD markers included dynamic contrast-enhanced MRI (DCE-MRI) and circulating sVEGFR-2 and VEGF levels assessed at each cycle. Tumor response was evaluated per RECIST criteria. Results: 22 patients (pts) with documented progressive disease were enrolled at doses of 10 mg to 120 mg once daily. Tumor types included CRC (27%), RCC (18%) and pancreatic cancer (14%). Pts had received a median of 3 prior therapies, including anti-VEGF agents in 5 pts. BAY 73–4506 PK appeared linear with dose; the AUC target exposure level of 13 mg*h/L (from preclinical models) was reached at 30 mg. The major metabolite of BAY 73–4506 (active in vitro) reached a similar AUC(0–24)ss as the parent drug at 120 mg. Commonly reported drug-related adverse events (=10% of pts) were hoarseness (7 [32%], all CTC grade 1), hypertension (5 [23%], all CTC grade 1–2), fatigue (3 [14%], CTC grade 3 in 1 pt [5%]), hand-foot-skin reaction (HFSR) (3 [14%], CTC grade 3 in 1 pt [5%], mucositis (3 [14%], all CTC grade 1). Maximum tolerated dose was exceeded at 120 mg with dose-limiting toxicities including fever without documented infection, HFSR, fatigue, and leukopenia. 2 pts (RCC & osteosarcoma) achieved RECIST partial response. 4 pts had stable disease, one of them a cervical cancer pt with extensive tumor cavitation. PD parameters (decrease in sVEGFR-2 levels, decrease in iAUC60s of Gd-DTPA by DCE-MRI) correlated with drug exposure. Conclusions: BAY 73–4506 was well tolerated at 60 mg with report of dose-limiting toxicities at 120 mg. 6 (28%) of 22 pts demonstrated antitumor activity. Optimal dose and regimen are under evaluation in preparation for phase II trials.

No significant financial relationships to disclose.

A phase Ib study of telatinib (BAY 57–9352), a VEGFR-2 inhibitor, in combination with docetaxel in patients with advanced solid tumours

14035

Background: Telatinib (BAY 57–9352) inhibits VEGFR-2 and VEGFR-3 tyrosine kinases, and PDGFR-β and c-Kit. Preclinical data suggests that targeting VEGFR signaling increases antitumor activity. Methods: This trial investigated the safety, pharmacokinetics (PK), and tumor efficacy of telatinib combined with docetaxel (D). D was administered at a fixed dose of 75mg/m2 on day 1 of 21-day cycles. Telatinib was administered orally, twice daily (bid) from day 3 of Cycle 1 and onwards, thereafter continuously. Dosing of telatinib commenced at 600mg bid (cohort 1, n=6) and increased to 900mg bid (cohort 2, n=7). PK in Cycle 1 were determined on day 1 (D) and day 21 (telatinib). In Cycle 2 comparative PK profiles for both telatinib and D were sampled on days 1–3. Results: Thirteen patients (pts) with advanced solid tumors were enrolled (9M/4F; median age: 56 [range: 34–69]; ECOG PS 0/1: 3/10). A total of 69 cycles have been completed (range,1–10). Treatment-emergent adverse events of CTCAE =3 (NCI-CTC v3.0) were neutropenia (n=11, 79%), fever (n=2, 15%), and fatigue (n=2, 11%). Adverse events of CTC =3 occuring in two pts was febrile neutropenia. Others occurring in only one patient were; hypertension, ALT increase, dehydration, and reversible symptomatic pneumonitis. Study treatment-related adverse events leading to a dose reduction or interruption were neutropenia (n=5, 38%), hypertension (n=1), ALT increase (n=1), and fatigue (n=1). Two pts with prostate ca and 1 with cervical ca had a confirmed partial response. Five pts (1 NSCLC, 1 esophageal ca, 1 renal cell ca and 2 prostate ca) had stable disease for =4 cycles. Mean AUC of D increased by 48% in cohort 1, but only by 16% in cohort 2. Thus, PK data to date do not indicate a clear clinically relevant interaction between telatinib and D. Conclusions: The combination of telatinib and D was tolerated without reaching the toxic dose at telatinib 900mg bid and D 75mg/m2. This combination has demonstrated promising antitumor activity. An extension of the cohort at 900mg bid with 75mg/m2 D is being evaluated to gain further safety and PK data.

No significant financial relationships to disclose.

Results from an in vitro and a clinical/pharmacological phase I study with the combination irinotecan and sorafenib

PURPOSE

This single-centre, open-label, phase I dose-escalation study was performed to investigate the safety, pharmacokinetics (PK) and efficacy of sorafenib, a multi-kinase inhibitor, combined with irinotecan, a cytotoxic agent, in patients with advanced, refractory solid tumours.

PATIENTS AND METHODS

In an initial dose-escalation phase, patients received irinotecan 125 mg/m(2) and sorafenib 100, 200 and 400 mg twice daily (bid) (cohorts 1-3). In an extended phase, colorectal cancer (CRC) patients received fixed-dose irinotecan 140 mg and sorafenib 400 mg bid (cohort 4).

RESULTS

Thirty-four patients were treated: 20 in the dose-escalation phase (common tumour types: CRC [45%], ovarian [5%], pancreatic [5%]) and 14 patients in the CRC extension. Frequent drug-related adverse events were gastrointestinal symptoms, dermatological reactions and constitutional symptoms. The maximum tolerated dose was not reached. Generally, concomitant administration of irinotecan had no impact on the PK of sorafenib. Sorafenib 100 or 200 mg bid had no impact on the PK of irinotecan or its metabolite SN38. In contrast, sorafenib 400 mg bid significantly increased irinotecan and SN38 exposures; however, this was not associated with increased toxicities. Stable disease was achieved in 12/20 (60%) evaluable patients in cohorts 1-3, and 10/13 (77%) evaluable patients in cohort 4. A further patient from cohort 4 had a partial response of >200 days. The increase of SN38 exposure might be due to inhibition of formation of the SN38 glucuronide by sorafenib. In vitro, sorafenib strongly inhibited SN38 glucuronidation in human liver microsomes as indicated by a K(i) value of 2.7 micromol/l.

CONCLUSION

Sorafenib 400 mg bid can be combined with irinotecan 125 mg/m(2) or 140 mg for the treatment of patients with advanced, refractory solid tumours, although monitoring for toxicity is recommended.

Phase I study of BAY 57–9352, a VEGFR-2 inhibitor, in cycles of 14 days on/7 days off in patients with advanced solid tumors

3089

Background: BAY 57–9352 (BAY) inhibits the VEGFR-2 and VEGFR-3 tyrosine kinases, in addition to PDGFR-β and c-kit. BAY showed anti-tumor activity in colon, breast, pancreatic, and NSCLC preclinical models. Methods: This study investigated the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of oral BAY in 14 days on/7 days off treatment cycles until discontinuation due to toxicity or progression. PK was assessed on days 1 and 14 of cycle 1. Dynamic contrast-enhanced MRI (DCE-MRI) was performed at baseline and in cycles 1–3. Plasma biomarkers (VEGF, sVEGFR-2) were assessed at each cycle. Results: 77 patients (pts) were enrolled at doses from 20 mg once daily to 1500 mg twice daily (bid). Common tumor types were CRC (31%) and RCC (16%). Frequent drug-related adverse events (≥5% pts) were hypertension (all grades, 11 pts [14%]; grade 3, 10 [13%]), hoarseness (10 [13%], only grade 1/2), anorexia (7 [9%], only grade 1/2), myalgia (6 [8%], only grade 1/2), fatigue (5 [6%], only grade 1/2), and diarrhea (all grades, 4 [5%]; grade 3, 1 [1%]). Hypertension in cycle 1 caused a dose reduction/interruption in 3 pts. One pt had diarrhea in cycle 7 requiring a dose reduction. One pt discontinued due to fatigue in cycle 8. BAY AUC increased dose-proportionally up to 900 mg bid. As measured by DCE-MRI, pts with CRC showed the greatest decrease in iAUC60 of Gd-DTPA, a parameter related to tumor blood flow and permeability. One pt with RCC achieved a partial response (PR); another had significant tumor shrinkage not reaching formal criteria (RECIST) for PR. PD responses (VEGF and sVEGFR-2 levels) increased in a dose-dependent manner up to 900 mg bid. Conclusions: The MTD was not reached for BAY up to 1500 mg bid in a 14 days on/7 days off schedule. BAY had a favorable safety profile. Tumor efficacy was shown in individual patients. The PD effect of BAY was demonstrated by DCE-MRI and plasma biomarkers. The recommended dose for Phase II evaluations is 900 mg bid.

[Table: see text]

VEGFR2 blockade in patients with solid tumors: Mechanism of hypertension and effects on vascular function

3037

Background: Hypertension is the most common side effect in trials with inhibitors of vascular endothelial growth factor (VEGF) signaling, although the underlying pathophysiology is unclear. As the use of anti-VEGF therapy is increasing, hypertension and related serious adverse events are likely to become more important. Methods: To better understand this pathophysiology,blood pressure and vascular function parameters were assessed in this substudy of a phase I trial in patients with advanced solid tumours treated with BAY 57–9352, an oral VEGF receptor 2 (VEGFR2) inhibitor. Blood pressure, flow-mediated dilatation (FMD), nitroglycerin-mediated dilatation (NMD) and pulse-wave velocity (PWV) were measured at baseline and after 5 weeks of daily treatment in 10 patients. Patients were spread out over different cohorts, taking different dosages of study drug. Results: Mean systolic blood pressure increased from 129.0 mm Hg to 139.4 mm Hg after 5 weeks of treatment (difference 10.4 mm Hg; 95% confidence interval (CI) 5.0–15.7 mm Hg; p=0.002). Mean diastolic blood pressure increased from 80.9 to 87.4 mm Hg (difference 6.5 mm Hg; 95% CI 1.7–11.3; p=0.013). Endothelium-dependent vasodilatation (FMD) decreased from 5.6% to 3.0% (95% CI 1.1–3.9%; p=0.003). NMD, indicating endothelium-independent vasodilatation, also decreased from 12.9% to 7.7% (95% CI 2.7–7.6%; p=0.001). Arterial stiffness (PWV), increased from 9.4 m/s to 10.3 m/s (p=0.07). Conclusions: Inhibition of VEGFR2 significantly increases systolic and diastolic blood pressure. As VEGF enhances endothelial nitric oxide (NO) synthetase activity, the clear decrease in FMD could be explained by reduced bioavailability of NO. The decrease in NMD may be a direct effect of VEGFR2 inhibition on vascular smooth muscle cells. However, a more likely hypothesis for these profound vascular effects is a reduced number of microvessels (i.e. rarefaction). As the microcirculation is largely responsible for peripheral resistance, the rarefaction associated with VEGFR2 inhibition is likely to increase peripheral resistance and lead to hypertension.

[Table: see text]

VEGF, sVEGFR-2, bFGF, and IL-8 as biomarkers of the pharmacological activity of BAY 57–9352, an oral VEGFR-2 receptor tyrosine kinase inhibitor, in patients with solid tumors

3035

Background: BAY 57–9352 (BAY) is a potent anti-angiogenic drug that inhibits VEGFR-2, as well as VEGFR-1, VEGFR-3, PDGFR-β, and c-Kit tyrosine kinases. Molecular biomarkers of angiogenesis (VEGF165, soluble VEGFR-2 [sVEGFR-2], basic FGF [bFGF], and interleukin-8 [IL-8]) were used to assess the pharmacodynamic effects of BAY. Methods: Patients with advanced solid tumors from two Phase I studies received oral BAY on either an intermittent 21 day cycle (14 days on drug, 7 days off drug) or continuous schedule (21 day cycle). Doses were escalated from 20 mg once daily (od) to 1500 mg twice daily (bid). Molecular biomarkers were measured at baseline, pre-dose, and 8 hours post-dose on Days 1 and 14 of each cycle. Pharmacokinetic parameters of BAY were also assessed. Results: Plasma samples from 130 patients were analyzed for angiogenic biomarkers. Increased VEGF165 and decreased sVEGFR-2 clearly correlated with the dose of BAY, respectively. All clinical responders (as shown by tumor shrinkage) were located within the upper 10% of the total response distribution for these markers. Subgroup analysis in the three more prevalent tumors showed that patients with colorectal, renal cell, and hepatocellular carcinoma all showed biomarker responses exceeding the mean overall responses. Biomarker levels reached a plateau at daily doses of approximately 900 mg bid or 1800 mg, suggesting a saturated pharmacodynamic effect. There were no consistent changes in bFGF and IL-8. Conclusions: Both VEGF and sVEGFR-2 demonstrated a dose-dependent change with BAY 57–9352. VEGF and sVEGFR-2 may be appropriate biomarkers of the therapeutic effects of BAY, and may be useful as potential predictors of early response.

[Table: see text]

Results of a Phase I trial of sorafenib (BAY 43-9006) in combination with doxorubicin in patients with refractory solid tumors

BACKGROUND

Sorafenib (BAY 43-9006), a novel, oral multi-kinase inhibitor, blocks serine/threonine and receptor tyrosine kinases in the tumor and vasculature. Sorafenib demonstrated single-agent activity in Phase I studies, and was tolerated and inhibited tumor growth in combination with doxorubicin in preclinical studies. This Phase I dose-escalation study determined the safety, pharmacokinetics and efficacy of sorafenib plus doxorubicin.

PATIENTS AND METHODS

Thirty-four patients with refractory, solid tumors received doxorubicin 60 mg/m(2) on Day 1 of 3-week cycles, and oral sorafenib from Day 4 of Cycle 1 at 100, 200 or 400 mg bid.

RESULTS

Common drug-related adverse events were neutropenia (56%), hand-foot skin reaction (44%), stomatitis (32%), and diarrhea (32%). The maximum tolerated dose was not reached. One patient with pleural mesothelioma achieved a partial response (modified WHO criteria) and remained on therapy for 39.7 weeks. Fifteen patients (48%) achieved stable disease for >/=12 weeks. Doxorubicin exposure increased moderately with sorafenib 400 mg bid. The pharmacokinetics of sorafenib and doxorubicinol were not affected.

CONCLUSION

Sorafenib 400 mg bid plus doxorubicin 60 mg/m(2) was well tolerated. The increased doxorubicin exposure with sorafenib 400 mg bid did not result in significantly increased toxicity; low patient numbers make the clinical significance of this unclear. These promising efficacy results justify further clinical investigation.

Pooled safety analysis of BAY 43-9006 (sorafenib) monotherapy in patients with advanced solid tumours: Is rash associated with treatment outcome?

In this analysis of the safety and efficacy of BAY 43-9006 (sorafenib) -- a novel, oral multi-kinase inhibitor with effects on tumour and its vasculature -- pooled data were obtained from four phase I dose-escalation trials. Time to progression (TTP) was compared in patients with/without grade 2 skin toxicity/diarrhoea. Grade 3 hand-foot skin reactions (HFS; 8%) and diarrhoea (6%) were common. At the recommended 400mg bid dose for phase II/III trials (RDP), 15% of patients experienced grade 2/3 HFS, and 24% experienced grade 2/3 diarrhoea. Sorafenib induced stable disease for 6 months in 12% of patients (6% stabilized for 1 year). Patients receiving sorafenib doses at or close to the RDP, who experienced skin toxicity/diarrhoea, had a significantly increased TTP compared with patients without such toxicity (P < 0.05). Sorafenib was well tolerated at the RDP, and induced sustained disease stabilization, particularly in patients with skin toxicity/diarrhoea.

Binding and repair of mismatched DNA mediated by Rhp14, the fission yeast homologue of human XPA

Rhp14 of Schizosaccharomyces pombe is homologous to human XPA and Saccharomyces cerevisiae Rad14, which act in nucleotide excision repair of DNA damages induced by ultraviolet light and chemical agents. Cells with disrupted rhp14 were highly sensitive to ultraviolet light, and epistasis analysis with swi10 (nucleotide excision repair) and rad2 (Uve1-dependent ultraviolet light damage repair pathway) revealed that Rhp14 is an important component of nucleotide excision repair for ultraviolet light-induced damages. Moreover, defective rhp14 caused instability of a GT repeat, similar to swi10 and synergistically with msh2 and exo1. Recombinant Rhp14 with an N-terminal hexahistidine tag was purified from Escherichia coli. Complementation studies with a rhp14 mutant demonstrated that the tagged Rhp14 is functional in repair of ultraviolet radiation-induced damages and in mitotic mutation avoidance. In bandshift assays, Rhp14 showed a preference to substrates with mismatched and unpaired nucleotides. Similarly, XPA bound more efficiently to C/C, A/C, and T/C mismatches than to homoduplex DNA. Our data show that mismatches and loops in DNA are substrates of nucleotide excision repair. Rhp14 is likely part of the recognition complex but alone is not sufficient for the high discrimination of nucleotide excision repair for modified DNA.

Frequency analysis of autoreactive T-helper 1 and 2 cells in bullous pemphigoid and pemphigus vulgaris by enzyme-linked immunospot assay

BACKGROUND

Bullous pemphigoid (BP) and pemphigus vulgaris (PV) are autoimmune bullous skin diseases mediated by autoantibodies against adhesion molecules of the skin. Previous studies have identified autoreactive T cells in patients with BP and PV, which may be critical in providing B-cell help for autoantibody production.

OBJECTIVES

To evaluate the frequency of autoreactive T-helper (Th) 1 and Th2 cells in patients with BP (n = 7) or PV (n = 1) and in healthy controls (n = 11).

METHODS

In an enzyme-linked immunospot (ELISPOT) assay, microtitre plates were coated with antihuman interleukin (IL)-5 IgG or antihuman interferon (IFN)-gamma IgG prior to culturing human peripheral blood lymphocytes (PBL) with BP180 or desmoglein (Dsg) 3 proteins for 7 days. Cytokine-producing autoreactive T cells were visualized as spot-forming units.

RESULTS

One BP patient with extensive blisters had 5.1 +/- 1.5 (mean +/- SD) BP180-reactive Th1 cells and 2.9 +/- 1.5 Th2 cells per 105 PBL. In contrast, PBL from six BP patients in remission or on immunosuppressive therapy did not form IFN-gamma- or IL-5-producing spots per </= 5 x 105 PBL. The patient with oral PV had 4.7 +/- 2.4 Th1 cells and 3.0 +/- 0.4 Th2 cells per 105 PBL and a vigorous PBL response to Dsg3. In addition, three of 10 controls had BP180-reactive Th1 (2.7-13.8 per 105 PBL) and Th2 (0.3-1.8 per 105 PBL) cells and one control had 9.0 +/- 0.7 Th1 cells and 1.1 +/- 0.8 Th2 cells per 105 PBL, with reactivity to Dsg3. ELISPOT reactivity correlated with 3H-thymidine incorporation in six of seven patients and controls with autoreactive T-cell responses.

CONCLUSIONS

The ELISPOT assay seems to be promising for the quantitative and qualitative analysis of autoreactive T-cell responses in BP and PV.

An open study of efficacy and safety of long-term treatment with mometasone furoate fatty cream in the treatment of adult patients with atopic dermatitis

BACKGROUND

Atopic dermatitis is a severe chronic skin disease often deteriorated by the presence of microorganisms and often responds well to treatment with potent corticosteroids. However, the long-term use of potent topical corticosteroids are accompanied by side-effects such as skin atrophy.

OBJECTIVE

To study the effect and safety of prophylactic treatment with mometasone furoate fatty cream (contains hexylene glycol) for 6 months in patients with atopic dermatitis.

RESULTS

Sixty-one of 68 (90%) patients were still free of their disease after 6 months of twice weekly treatment and only one showed possible treatment related signs of skin atrophy. The number of Staphylococcus aureus and Pityrosporum ovale were significantly reduced in cleared patients.

CONCLUSIONS

Mometasone furoate fatty cream is effective and safe both for treatment and as a prophylaxis in patients with atopic dermatitis.

Vaccination of multiple myeloma patients with idiotype-pulsed dendritic cells: immunological and clinical aspects

Multiple myeloma (MM) is characterized by a clonal proliferation of malignant plasma cells in the bone marrow secreting a monoclonal immunoglobulin (paraprotein) with specific antigenic determinants, the idiotype (Id), which can be regarded as a tumour-associated antigen (TAA). In order to analyse the impact of a dendritic cell (DC)-based vaccine, 11 patients with advanced MM were treated with CD34 stem cell-derived dendritic cells that were pulsed with Id peptides. Subsequently, the patients received three boost immunizations every other week with a combination of Id and granulocyte-macrophage colony-stimulating factor (GM-CSF) (nine patients) or with Id peptide-pulsed dendritic cells again (two patients). The treatment was well tolerated with no side-effects. The present clinical study was a proof of concept analysis of dendritic cell-based vaccines in MM. The capacity of the dendritic cells to activate idiotype-specific T cells was verified by in vitro stimulation experiments before the vaccination therapy. Immunological effects of the Id vaccination were analysed by monitoring changes in anti-idiotype antibody titres and idiotype-specific T-cell activity. After vaccination, three out of 10 analysed patients showed increased anti-idiotype antibody serum titres, indicating the induction of an idiotype-specific humoral immune response. The idiotype-specific T-cell response analysed by ELISpot was increased in four out of 10 analysed patients after vaccination, and one patient had a decreased plasma cell infiltration in the bone marrow. In conclusion, five out of 11 patients showed a biological response after vaccination. Thus, our data indicate that immunotherapy with Id-pulsed DCs in MM patients is feasible and safe. DC generated from CD34+ progenitor cells can serve as a natural adjuvant for the induction of clinically relevant humoral and cellular idiotype-specific immune responses in patients suffering from advanced MM.

[Fatal poisoning with Letigen]

The anorexic agent Letigen, which contains 200 mg coffeine and 20 mg ephedrine, has been extensively used during the last decade. The case report describes a 19 year-old woman who ingested 50 Letigen tablets in a suicidal attempt. She developed severe toxic manifestations from the heart, CNS, muscles, liver and kidneys leading to several cardiac arrests, and died subsequently of cerebral oedema and incarceration on the fourth day of hospitalization. Because of the potentially life-threatening intoxication following an overdose, prescription of Letigen must be carefully administered.

Expression and a role of functionally coupled P2Y receptors in human dendritic cells

We investigated the physiology and function of P2Y receptors expressed in human dendritic cells (DCs) differentiated in vitro from CD14+ cells (DC-14). These were obtained after a 10 day stimulation period in GM-CSF, IL-4 and monocyte conditioned medium. DC-14 were found to express high amounts of MHC class II, B7, CD40 as well as CD83. The functional analysis, using single cell Ca2+ imaging, demonstrated the expression of at least three subtypes of P2Y receptors. We further found using patch-clamp measurements that ATP evoked a pertussis toxin insensitive non-selective cation current with a peak current amplitude of -276+/-43 pA (holding potential -80 mV, n = 23). This current was not Ca(2+)-activated, since it was still observed under conditions of high intracellular Ca2+ buffering and could be blocked by Gd3+ (0.5 mM). In addition, intracellular application of GTP-gamma-S (0.3 mM) also activated the current. Interestingly, DC-14 redirected the orientation of their dendrites as well as cell shape towards a pipette containing ATP as observed with time lapse microscopy. These data suggest that in human DCs, ATP acts via P2Y receptors and induces chemokine effects.

[Cardiac manifestations in osteogenesis imperfecta. A case report and therapeutic implications]

Osteogenesis imperfecta is an hereditary defect in the synthesis of collagen fibres. The disease can cause cardiac defects, such as aortic and mitral incompetence. Surgical repair of these defects is complicated by tissue friability and bleeding problems. We describe a case where an incompetent aortic valve was successfully replaced by a mechanical prosthesis.

[Adverse effects of selective serotonin uptake inhibitors. Hyponatremia caused by Schwartz-Bartter syndrome]

This report describes three cases of hyponatraemia/syndrome of inappropriate secretion of antidiuretic hormone. The cases are most likely caused by treatment/intoxication with three different selective serotonin reuptake inhibitors: Fluoxetine, paroxetine and citalopram. All three patients were elderly women (75-83 years). Serum sodium values returned to normal or near normal after discontinuation of the drug and concomitant fluid restriction. Hyponatraemia has previously been described as an adverse effect to fluoxetine and paroxetine, but not to citalopram.

Analgesic effect of intraarticular morphine. A controlled, randomised and double-blind study

BACKGROUND

Opioids produce antinociceptive effect by acting on receptors on peripheral nerves. The clinical relevance of this effect is still debated. The aim of the study was to compare the analgesic effect of morphine intraarticularly with the intramuscular route of administration after knee surgery.

METHODS

Sixty-one patients, ASA 1-2, having elective arthroscopic surgery of the knee were randomised to either an intraarticular or intramuscular dose of morphine 5 mg. The pain sensation was estimated by visual analogue scale and a verbal rating score 0, 1, 2 and 4 hours postoperatively and verbal rating score on the third day. The use of acetaminophen and supplementary opioids were recorded for the first 4 hours postoperatively, from 4 hours until the third day, and from day 3 to day 7 postoperatively.

RESULTS

The groups were comparable. Three patients were excluded. There were no statistically significant differences in painscore and consumption of analgesics. Fifty-nine per cent in each group had macroscopic synovitis. In the intraarticular group, there was no increased effect of morphine in the patients with synovitis compared to patients without synovitis.

CONCLUSIONS

The clinical analgesic effect of 5 mg morphine given intraarticularly is equal to 5 mg morphine given intramuscularly. The occurrence of villous synovitis seems to be of no clinical importance concerning the local effect of morphine.

Effects of thoracic epidural analgesia on pulmonary function after coronary artery bypass surgery

OBJECTIVE

A substantial reduction in lung volumes and pulmonary function follows cardiac surgery. Pain may prevent effective breathing and coughing, and as thoracic epidural analgesia may reduce postoperative pain, we investigated the effect of epidural analgesia on pulmonary function.

METHODS

Fifty-four male patients, under 65 years and with an ejection fraction of more than 0.5, were randomized into two groups: a control group receiving high-dose fentanyl anaesthesia and an epidural group receiving low-dose fentanyl anaesthesia + thoracic epidural analgesia. Time to awakening and time to extubation were recorded. Further, spirometric data, arterial oxygenation, pulmonary shunt, haemodynamics, use of vasoactive drugs and fluid balance were followed for up to 6 days postoperatively.

RESULTS

Patients with low-dose fentanyl and epidural analgesia awoke (1.6 vs 3.6 h) and were extubated (5.4 vs 10.8 h) significantly earlier than control group patients. A 50-70% reduction in forced vital capacity, forced expiratory volume in 1 s (FEV1.0) and peak expiratory flow rate (PEFR) was seen after surgery, but higher FEV1.0 and PEFR on days 2 and 3 were seen in the epidural group than in the control group. Pulmonary shunt and alveolo-arterial oxygen difference increased similarly in both groups, whereas oxygen delivery and mixed venous oxygen saturation were higher in the epidural group. Epidural analgesia gave better control of the postoperative hyperdynamic circulation.

CONCLUSIONS

Thoracic epidural analgesia yields a slight, but significant, improvement in pulmonary function, most likely due to a more profound postoperative analgesia.

Effects of thoracic epidural analgesia on coronary hemodynamics and myocardial metabolism in coronary artery bypass surgery

OBJECTIVE

A possible influence of thoracic epidural analgesia on coronary hemodynamics and myocardial metabolism in coronary artery bypass grafting was investigated.

DESIGN

The study was prospective and randomized.

SETTING

The study was performed in a university hospital.

PARTICIPANTS

Thirty male patients less than 65 years of age and with ejection fraction greater than 0.5 participated. They were randomized into 3 groups: the high fentanyl (HF) group receiving high-dose fentanyl (55 micrograms/kg) anesthesia, the HF + thoracic epidural analgesia (TEA) group receiving the same general anesthesia plus thoracic epidural analgesia, and the low-fentanyl (LF) + TEA group receiving low-dose fentanyl (15 micrograms/kg) anesthesia plus thoracic epidural analgesia.

INTERVENTIONS

A thoracic epidural catheter, a peripheral and central venous catheter, a radial artery catheter, a thermodilution pulmonary artery catheter, and a coronary sinus reverse thermodilution catheter were inserted.

MEASUREMENTS AND MAIN RESULTS

Coronary circulatory parameters, myocardial oxygenation, and myocardial substrate utilization were investigated before bypass and for 9 hours after bypass. Before bypass, the most striking finding was a reduction in myocardial lactate extraction in all groups, but also coronary flow and myocardial oxygen consumption decreased compared with baseline. After bypass, the only significant finding was a lower coronary vascular resistance early postoperatively in the epidural groups, but coronary blood flow was adequate in all groups. Myocardial metabolism was essentially unchanged both with and without epidural analgesia after bypass.

CONCLUSION

With regard to the coronary circulation and myocardial metabolism, no hard data supporting the use of thoracic epidural analgesia in coronary artery bypass grafting were found.

Thoracic epidural analgesia in aortocoronary bypass surgery. I: Haemodynamic effects

Tachycardia and hypertension may cause myocardial ischaemia in patients with coronary heart disease going through major surgery. Thoracic epidural analgesia (TEA) has been reported to be beneficial in this situation. The haemodynamic effects of TEA in aortocoronary bypass surgery were investigated in 30 male patients < 65 years old and with ejection fraction > 0.5. They were randomized into 3 groups: the high dose fentanyl (HF) group receiving high-dose fentanyl (55 micrograms.kg-1) anaesthesia, the HF+TEA group receiving the same fentanyl dose+TEA with 10 ml bupivacaine 5 mg.ml-1 followed by 4 ml every hour, and the low dose fentanyl (LF) + TEA group receiving low-dose fentanyl (15 micrograms.kg-1) anaesthesia+TEA. Haemodynamic parameters, the use of vasoactive and inotropic drugs and fluid balance were followed during the operation and for 20 h postoperatively. Before bypass the only significant difference between groups was a higher mean pulmonary arterial pressure in the HF+TEA group and a lower systemic vascular resistance (SVR) in the LF+TEA group, both compared to the HF group. 89% of epidural group patients needed small doses of ephedrine whereas more HF group patients were given nitroglycerine. During bypass SVR and mean arterial pressure (MAP) were significantly higher and pump flow lower in the HF group compared to the LF+TEA group. More ketanserin to HF group patients and methoxamine to epidural group patients were given. After bypass heart rate increased in all groups. Lower MAP 0.5 h after bypass and higher filling pressures in the early post bypass period in the epidural groups, most pronounced in the HF+TEA group, were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Thoracic epidural analgesia in aortocoronary bypass surgery. II: Effects on the endocrine metabolic response

Thoracic epidural analgesia (TEA) may offer haemodynamic benefits for patients with coronary heart disease going through major surgery. This may-in part-be secondary to an effect on the endocrine and metabolic response to surgery. We therefore investigated the effect of TEA on the endocrine metabolic response to aortocoronary bypass surgery (ACBS). Thirty male patients (age < 65 years, ejection fraction > 0.5) were randomized into 3 groups; the HF group receiving a high dose fentanyl (55 micrograms.kg-1) anaesthesia, the HF+TEA group with the same fentanyl dose+TEA with 10 ml bupivacain 5 mg.ml-1, followed by 4 ml every hour, and the LF+TEA group receiving fentanyl 15 micrograms.kg-1 + TEA. Adrenalin, noradrenalin, systemic vascular resistance (SVR), glucose, cortisol, lactate and free fatty acids were followed during the operation and for 20 h postoperatively. A significant increase in adrenalin, noradrenalin and SVR was found in the HF group whereas this increase was blocked in both epidural groups. An increase in glucose and cortisol was noticed in all groups, but the increase was delayed in the epidural groups. Our results suggest that a more effective blockade of the stress response during ACBS is obtained when TEA is added to general anaesthesia than with high dose fentanyl anaesthesia alone.

[The circulating occupational medical record in the county of Roskilde]

The aim of the circulating occupational medical record (COMR) is to coordinate activities and documents concerning the patient who has an occupational disease. This new case record belongs to the patient, which solves the problems concerning the professional secrecy of the involved authorities. The general practitioner, the trade union and amongst others the safety organisation of the work place all have their own schematic pages in the record. The number and use of COMRs were studied. Postal questionnaires were sent to the primary users of the COMRs. Altogether 345 COMRs were started over the two year period 1989-1991. Two hundred and ninety-eight COMRs were evaluable. The page of the general practitioner was used in 90% of the records, versus 64% in the case of the unionpage and 21% in the case of the safety organisation. In 78% there were documents from medical specialists, psychologists or physiotherapists. The majority of the documents were from the department of occupational medicine. In half of the COMRs there were documents from more than four different sources. Only 76% of the patients were referred to the department of occupational medicine. It is recommended that the COMR should be extended to the whole country.

The influence of thoracic epidural analgesia alone and in combination with general anesthesia on cardiovascular function and myocardial metabolism in patients receiving beta-adrenergic blockers

Thoracic epidural analgesia combined with chronic beta-adrenergic blocker medication may cause cardiac depression. We investigated the cardiovascular and myocardial metabolic effects of a T1-T12 epidural block in 18 patients (age < 65 yr, ejection fraction > 0.5), receiving chronic beta-adrenergic blocker medication and scheduled for aortocoronary bypass surgery. After randomization into a light or deeper general anesthetic group, the cardiovascular and myocardial metabolic effects of a subsequent general anesthesia induction were investigated. Thoracic epidural analgesia induced a moderate decrease in mean arterial pressure, coronary perfusion pressure, free fatty acids, and myocardial consumption of free fatty acids. General anesthesia with thiopental (2-4 mg/kg) and a low fentanyl dose (5 micrograms/kg) increased heart rate, coronary perfusion pressure, and coronary vascular resistance, whereas mean pulmonary arterial pressure and pulmonary capillary wedge pressure decreased. After thiopental (2-4 mg/kg) and a high fentanyl dose (30 micrograms/kg), mean arterial pressure and left ventricular stroke work index decreased. We conclude that a T1-T12 epidural block in well sedated, beta-adrenergic blocked patients does not induce clinically significant cardiovascular effects. Induction of general anesthesia was well tolerated, but the light general anesthetic could not prevent an increase in heart rate and coronary vascular resistance, whereas the deeper anesthetic induced slight myocardial depression. No effect on the atrioventricular conduction, as measured by the PQ-time, was noted.

Cell swelling activates K+ and Cl- channels as well as nonselective, stretch-activated cation channels in Ehrlich ascites tumor cells

Cell-attached patch-clamp recordings from Ehrlich ascites tumor cells reveal nonselective cation channels which are activated by mechanical deformation of the membrane. These channels are seen when suction is applied to the patch pipette or after osmotic cell swelling. The channel activation does not occur instantaneously but within a time delay of 1/2 to 1 min. The channel is permeable to Ba2+ and hence presumably to Ca2+. It seems likely that the function of the nonselective, stretch-activated channels is correlated with their inferred Ca2+ permeability, as part of the volume-activated signal system. In isolated inside-out patches a Ca(2+)-dependent, inwardly rectifying K+ channel is demonstrated. The single-channel conductance recorded with symmetrical 150 mM K+ solutions is for inward current estimated at 40 pS and for outward current at 15 pS. Activation of the K+ channel takes place after an increase in Ca2+ from 10(-7) to 10(-6) M which is in the physiological range. Patch-clamp studies in cell-attached mode show K+ channels with spontaneous activity and with characteristics similar to those of the K+ channel seen in excised patches. The single-channel conductance for outward current at 5 mM external K+ is estimated at about 7 pS. A K+ channel with similar properties can be activated in the cell-attached mode by addition of Ca2+ plus ionophore A23187. The channel is also activated by cell swelling, within 1 min following hypotonic exposure. No evidence was found of channel activation by membrane stretch (suction). The time-averaged number of open K+ channels during regulatory volume decrease (RVD) can be estimated at 40 per cell. The number of open K+ channels following addition of Ca2+ plus ionophore A23187 was estimated at 250 per cell. Concurrent activation in cell-attached patches of stretch-activated, nonselective cation channels and K+ channels in the presence of 3 mM Ca2+ in the pipette suggests a close spatial relationship between the two channels. In excised inside-out patches (with NMDG chloride on both sides) a small 5-pS chloride channel with low spontaneous activity is observed. The channel activity was not dependent on Ca2+ and could not be activated by membrane stretch (suction). In cell-attached mode single-channel currents with characteristics similar to the channels seen in isolated patches are seen. In contrast to the channels seen in isolated patches, the channels in the cell-attached mode could be activated by addition of Ca2+ plus ionophore A23187.(ABSTRACT TRUNCATED AT 400 WORDS)

Patency of the internal mammary artery used as sequential graft

In 28 patients with the left internal mammary artery (IMA) used as a sequential coronary artery graft, clinical and angiographic evaluation was made 19-47 months postoperatively. Patency was 96% in the proximal anastomoses and 93% in all the anastomoses. Angiography, however, showed optimal function in only 75% of the distal graft ends. These observations indicate that routine use of left IMA as a sequential graft should be restricted to experienced surgeons. Clinical and angiographic findings did not always correlate, emphasizing that evaluation of IMA-graft patency should include angiography.

Geographic stomatitis: report of 6 cases

The macro- and microscopic appearance and results of microbiologic and immunohistochemical investigations in six patients with geographic stomatitis are described. On the background of similarities in both the clinical, histologic and immunohistochemical findings it is felt that psoriasis and stomatitis geographica are related lesions.

Anion channels in a leaky epithelium. A patch-clamp study of choroid plexus

We have used the patch-clamp technique to characterize three anion channels in the ventricular membrane of the choroid plexus epithelium from Necturus. The most frequently occurring channel had a nonlinear IV-curve. The conductance in excised patches with 112 mM chloride at both sides was 28 pS at 0 mV, increasing towards positive membrane potentials. The selectivity ratios were PNa:PCl less than or equal to 0.1 and PNO3:PCl:PHCO3 = 1.6:1:0.43. SITS and furosemide (1 mM) on the inside reduces chloride flux to 0.15 and 0.37 times the control value. In attached patches, the most commonly observed channel had a conductance of 7.5 pS. The single-channel current for this channel reversed direction at 15 mV hyperpolarization, indicating accumulation of chloride to a factor of 1.8 above equilibrium. External stimulation of the tissue by theophylline, IBMX and dbcAMP, or by hypotonic shock did not increase the activity of this channel. In very few excised patches, we have observed a chloride channel with a conductance of 7 pS with 112 mM chloride at both sides. The 7 pS channel appears to be identical to a 2 pS channel found in attached patches. The 2 pS channel was not normally active in attached patches but was activated in 28% of the patches by external stimulation. Finally, in few excised patches we have found a 375 pS channel which inactivates within seconds when membrane potential is stepped from 0 mV to a value that differs more than 10-20 mV from zero. The channel did not conduct gluconate but PNO3:PCl = 1.08 and PNa:PCl less than or equal to 0.1. Internal SITS and furosemide (1 mM) reduced chloride flux to 0.3 and 0.5 times the control value. The channel was never seen in attached patches. The current carried through these channels can not account for the transepithelial steady state Cl- -flux measured by microelectrodes. KCl exit from the cell is suggested to be carried by KCl-cotransport or by channels that are too small to be seen in patch-clamp experiments.

Fat consumption and schizophrenia

This report describes the statistical association between the average ratings of course and outcome of schizophrenia in 8 national centres participating in the World Health Organization international 2-year follow-up study (1) and the amount of fat in the average national diets as published by the Food and Agriculture Organization of the United Nations (2). Highly significant correlations were found between favourable ratings of course and outcome of schizophrenia and a low percentage of total fat (r = 0.80-0.90; P less than 0.05) and of fat from land animals and birds (composed mainly of saturated fat) (r = 0.91-0.95; P less than 0.01). High percentage of fat from vegetables, fish and seafood (having a relatively high content of unsaturated fatty acids) tended to be associated with a favourable course and outcome (r = 0.23-0.50; P greater than 0.10). A multivariate analysis revealed that 97% (P = 0.0002) of the variation in the overall outcome of schizophrenia between the national centres could be explained by the combined variation in the percentages of fat from land animals and birds and from vegetables, fish and seafood, respectively, in the national diets. These results suggest that the course and outcome of schizophrenia may be influenced through diet. They should encourage investigators to perform controlled clinical trials of low-fat diets with a sufficient amount of essential fatty acids.

Transcapillary fluid balance in subcutaneous tissue of patients undergoing aortocoronary bypass with extracorporeal circulation

Colloid osmotic pressure in plasma (COPpl) from a cubital vein and in interstitial fluid (COPif) in the subcutaneous tissue at heart level, and interstitial fluid pressure (Pif) at the same level, were measured in 18 healthy subjects and in 28 patients requiring aortocoronary bypass. Interstitial fluid was collected via subcutaneously implanted double nylon wicks and Pif was measured with the 'wick-in-needle' technique. Measurements were made preoperatively and 1 1/2 to 8 hours (mean 4 hours) after termination of extracorporeal circulation. Pif rose to 2.3 mmHg above the pre-bypass level. COPpl concomitantly fell from 22.2 to 14.4 and COPif from 12.4 to 10.1 mmHg. These changes were statistically significant. Although the relatively large COPpl drop resulted in a net rise of 3.2 mmHg in filtration pressure, the incidence of pulmonary complications was low and no subcutaneous edema was discernible. The fall in COPif and rise in Pif may be regarded as important edema-preventing mechanisms.

Mediation of cell volume regulation by Ca2+ influx through stretch-activated channels

Animal cells initially swell in hypotonic media by osmotic water equilibration, but their volume is subsequently regulated by a net loss of KCl and amino acids with concomitant loss of cell water. Mechanisms for regulating cell volume are important in allowing cells to adapt to variations in external tonicity and metabolic load. In red cells the KCl loss is mediated by electroneutral ion transport mechanisms. In contrast, conductive K+ and Cl- transport pathways are activated during regulatory volume decrease in several cell types including epithelia. The activation seems to be mediated by internal Ca2+, but the detailed mechanism is not known. In a leaky epithelium, the choroid plexus epithelium, we have found a cation-selective, Ca2+-permeable channel which opens with membrane stretch. The epithelium also contains a high density of the large (approximately 200 pS) type of Ca2+- voltage-activated K+ channel. Both channels are normally closed. I propose that in hypotonic media, the stretching of the cell membrane produced by the initial swelling causes influx of Ca2+ through the stretch-activated channels, which activates the neighbouring large K+ channels to produce increased K+ outflux with associated loss of cell water.

The mechanism of electrodiffusive K+ transport in leaky epithelia and some of its consequences for anion transport

The ventricular membrane of the epithelium from the choroid plexus of Necturus maculosus was probed with double-barrelled ion-selective microelectrodes while the ventricular bathing solution was changed abruptly. The transient states induced by increasing the external concentration of K+ or by the application of ouabain showed that the passive movements of K+ across the ventricular membrane were electro-diffusive and could be described by the Goldmann equation and one constant permeability (PK) of 24 X 10(-6) cm s-1. The passive efflux was balanced by a ouabain-sensitive influx. PK was different in different steady states; when the cell was acidified by half a pH unit by increasing CO2 in the bathing solutions from 1 to 5%, then PK decreased to 13 X 10(-6) cm s-1. Removal of Cl- from the bathing solution increased PK by 50% and reduction of Cl- transport by furosemide did not alter PK, consequently major movements of K+ were independent of Cl- movements. Depolarizations of the cell caused an increase in the cellular HCO-3 concentration due to an electrodiffusive permeability (PHCO3), the value of which was estimated to 17 X 10(-6) cm s-1.

Electrodiffusion of Cl- and K+ in epithelial membranes reconstituted into planar lipid bilayers

An electrodiffusive permeability for Cl-, its activation by low extracellular Cl--concentrations and the interaction between electrodiffusive fluxes of Cl- and K+ are demonstrated in the ventricular membranes from the epithelium of the bovine choroid plexus. Membranes were fused into artificial lipid bilayers formed at the tip of micropipettes. What is thought to be the cytoplasmic side of the membrane (the trans-side or the inside of pipette) was clamped at negative potentials (0 to -90 mV). Under these conditions the current was discrete, fluctuating less than 2 pA. With Cl- as the only conducting ion on the two sides we observed a small electrodiffusive permeability which was reduced by bumetanide or furosemide by 62%. When the outside solution was rendered Cl--free then the permeability to Cl- increased by a factor of 2-5; this activation was reduced by bumetanide or furosemide by about 80%. We observed an interaction between inwards movements of K+ and outwards movements of Cl- via the activated permeability: The total current was smaller than the sum of the expected inward K+-current and the expected outward activated Cl--current. Bumetanide or furosemide increased the total current; apparently the loss of current carried by Cl- was smaller than the gain in current carried by K+. The presence of K+ on both sides of the membrane was a condition for this interaction.

Maxi K+ channels in leaky epithelia are regulated by intracellular Ca2+, pH and membrane potential

We have studied a Ca2+-activated K+ channel in the ventricular membrane of the epithelium of choroid plexus by means of the patch-clamp technique, using excised inside-out patches. The channel was highly K+ selective. It had a conductance of approximately 200 pS with 112 mM KCl on both sides of the membrane. The probability for the channel being open increased with intracellular Ca2+, pH and with membrane potential. The channel shows two gating modes. The primary gating mode has open and closed times which depend strongly on membrane potential, intracellular Ca2+ and pH. It accounts for the variation of the channel open probability. Lowering intracellular pH from 7.4 to 6.4 reduced the channel open probability mainly by increasing the channel closed time. It appears, that H+ can compete with Ca2+ in binding to the same site, thereby preventing channel opening. A second gating mode consisted of short-lived closures, or flickers. The open and closed time for this process were largely independent of membrane potential, intracellular Ca2+ and pH. The channel density was approximately 0.4 micron-2 corresponding to a K+-permeability of 2.2 10(-5) cm s-1 if the channels were fully open. In cell-attached patches we measured the open probability of the channel in the intact cell membrane. The channel is almost totally closed under normal cellular conditions. This type of channel is therefore not the membrane component that forms the electrodiffusive pathway for K+-ions.

Surgical treatment of aneurysms of the descending thoracic aorta

Six patients were operated on for aneurysm of the descending thoracic aorta in 1983-1985 by use of simple cross-clamping and interposition of a Dacron tube graft without extracorporeal circulation. The aneurysm had ruptured in three cases. The patients' mean age was 69 years. Anesthesia and muscle relaxation were obtained by drugs with only minor myocardial depressant action. There was no postoperative mortality or morbidity. Five of the patients have been followed up for at least a year. Careful pharmacologic control of the blood pressure is essential during such surgery. Despite the smallness of the series, it indicates that simple cross-clamping and Dacron graft interposition can be used for treatment of aneurysm of the descending thoracic aorta.

Early complications with a new bovine arterial graft (Solcograft-P)

In three separate centers of vascular surgery in Norway, a total of 26 patients underwent implantation of a new bovine arterial graft (Solcograft-P) for femoropopliteal or femorotibial bypass or arterial patch-plasty. Serious complications--graft deterioration and formation of aneurysm or pseudoaneurysm--arose in eight patients, all within 4 months after the implantation. In central Europe only four anastomotic pseudoaneurysms have been reported after about 700 Solcograft implantations, even with longer observation time. Possible causes of the difference in complication rates are discussed.