Complete regeneration of large bone defects in rats with commercially available fibrin loaded with BMP-2.

This study aimed at investigating in vitro and in vivo the efficiency of commercially available fibrin as a carrier for controlled and sustained bone morphogenetic protein-2 (BMP-2) release to induce bone formation and reduce the side effects of its use. In vitro release and activity of low-dose recombinant human BMP-2 (rhBMP-2) (37.5 µg/mL) embedded in commercially available fibrin were evaluated and, subsequently, critical-size femur defects in rats were grafted to study bone regeneration and vascularisation by micro-computed tomography (µCT) and histology. In vitro experiments showed a sustained BMP-2 release with a high BMP activity remaining after 28 d. In vivo, fibrin loaded with BMP-2 showed an extremely fast bone healing, with a large amount of new bone formation throughout the entire defect in the first 4 weeks and complete cortical repair and fusion after 8 weeks, with no ectopic bone formation. In contrast, the control fibrin group did not fuse after 12 weeks. Vascularisation was similar in both groups at 4 and 12 weeks after implantation. In conclusion, commercially available fibrin is a very efficient carrier for rhBMP-2 to graft critical-size cortical bone defects and might be a more optimal delivery vehicle for BMP-2-induced bone regeneration than currently available collagen sponges.

Full regeneration of segmental bone defects using porous titanium implants loaded with BMP-2 containing fibrin gels.

Regeneration of load-bearing segmental bone defects is a major challenge in trauma and orthopaedic surgery. The ideal bone graft substitute is a biomaterial that provides immediate mechanical stability, while stimulating bone regeneration to completely bridge defects over a short period. Therefore, selective laser melted porous titanium, designed and fine-tuned to tolerate full load-bearing, was filled with a physiologically concentrated fibrin gel loaded with bone morphogenetic protein-2 (BMP-2). This biomaterial was used to graft critical-sized segmental femoral bone defects in rats. As a control, porous titanium implants were either left empty or filled with a fibrin gels without BMP-2. We evaluated bone regeneration, bone quality and mechanical strength of grafted femora using in vivo and ex vivo µCT scanning, histology, and torsion testing. This biomaterial completely regenerated and bridged the critical-sized bone defects within eight weeks. After twelve weeks, femora were anatomically re-shaped and revealed open medullary cavities. More importantly, new bone was formed throughout the entire porous titanium implants and grafted femora regained more than their innate mechanical stability: torsional strength exceeded twice their original strength. In conclusion, combining porous titanium implants with a physiologically concentrated fibrin gels loaded with BMP-2 improved bone regeneration in load-bearing segmental defects. This material combination now awaits its evaluation in larger animal models to show its suitability for grafting load-bearing defects in trauma and orthopaedic surgery.

Chondrogenically differentiated mesenchymal stromal cell pellets stimulate endochondral bone regeneration in critical-sized bone defects.

Grafting bone defects or atrophic non-unions with mesenchymal stromal cells (MSCs)-based grafts is not yet successful. MSC-based grafts typically use undifferentiated or osteogenically differentiated MSCs and regenerate bone through intramembranous ossification. Endochondral ossification might be more potent but requires chondrogenic differentiation of MSCs. Here, we determined if chondrogenically differentiated MSC (ch-MSC) pellets could induce bone regeneration in an orthotopic environment through endochondral ossification. Undifferentiated MSC pellets (ud-MSC) and ch-MSC pellets were generated from MSCs of human donors cultured on chondrogenic medium for respectively 3 (ud-MSC) and 21 (ch-MSC) days. A 6 mm femoral bone defect was made and stabilised with an internal plate in 27 athymic rats. Defects were left empty for 6 weeks to develop an atrophic non-union before they were grafted with ch-MSC pellets or ud-MSC pellets. Micro-CT scans made 4 and 8 weeks after grafting showed that ch-MSC pellets resulted in significantly more bone than ud-MSC pellets. This regenerated bone could completely bridge the defect, but the amount of bone regeneration was donor-dependent. Histology after 7 and 14 days showed slowly mineralising pellets containing hypertrophic chondrocytes, as well as TRAP-positive and CD34-positive cells around the ch-MSC pellets, indicating osteoclastic resorption and vascularisation typical for endochondral ossification. In conclusion, grafting critical femoral bone defects with chondrogenically differentiated MSC pellets led to rapid and pronounced bone regeneration through endochondral ossification and may therefore be a more successful MSC-based graft to repair large bone defects or atrophic non-unions. But, since bone regeneration was donor-depend, the generation of potent chondrogenically differentiated MSC pellets for each single donor needs to be established first.

Gitelman's variant of Bartter's syndrome, inherited hypokalaemic alkalosis, is caused by mutations in the thiazide-sensitive Na-Cl cotransporter.

Maintenance of fluid and electrolyte homeostasis is critical for normal neuromuscular function. Bartter's syndrome is an autosomal recessive disease characterized by diverse abnormalities in electrolyte homeostasis including hypokalaemic metabolic alkalosis; Gitelman's syndrome represents the predominant subset of Bartter's patients having hypomagnesemia and hypocalciuria. We now demonstrate complete linkage of Gitelman's syndrome to the locus encoding the renal thiazide-sensitive Na-Cl cotransporter, and identify a wide variety of non-conservative mutations, consistent with loss of function alleles, in affected subjects. These findings demonstrate the molecular basis of Gitelman's syndrome. We speculate that these mutant alleles lead to reduced sodium chloride reabsorption in the more common heterozygotes, potentially protecting against development of hypertension.

Patients' representations of their end-stage renal disease: relation with mortality.

BACKGROUND: Self-regulation theory explains how patients' illness perceptions influence self-management behaviour (e.g. via adherence to treatment). Following these assumptions, we explored whether illness perceptions of ESRD-patients are related to mortality rates. METHODS: Illness perceptions of 182 patients participating in the NECOSAD-2 study in the period between December 2004 and June 2005 were assessed. Cox proportional hazard models were used to estimate whether subsequent all-cause mortality could be attributed to illness perception dimensions. RESULTS: One-third of the participants had died at the end of the follow-up. Mortality rates were higher among patients who believed that their treatment was less effective in controlling their disease (perceived treatment control; RR = 0.71, P = 0.028). This effect remained stable after adjusting for sociodemographic and clinical variables (RR = 0.65, P = 0.015). CONCLUSIONS: If we consider risk factors for mortality, we tend to rely on clinical parameters rather than on patients' representations of their illness. Nevertheless, results from the current exploration may suggest that addressing patients' personal beliefs regarding the effectiveness of treatment can provide a powerful tool for predicting and perhaps even enhancing survival.

Pleural drainage and pleurodesis: implementation of guidelines in four hospitals.

The aim of the present study was to evaluate the implementation of the 2003 Dutch guideline on the diagnosis and treatment of malignant pleural effusions, and the potential effect of the implementation on the clinical outcome of pleurodesis. All patients with malignant pleural effusion who had a pleural drain placed with the intention of performing pleurodesis were registered prospectively in four centres. Details of the procedure and fluid recurrence and survival data were noted. Patients with a proven malignancy (n = 100) were entered into the registration database. Diagnostic guideline recommendations were followed in 60-70% of the patients. Surprisingly, pleurodesis was performed in only 75% of the patients, mainly due to the presence of a trapped lung. All pleurodeses were performed using talc, according to the guideline. Follow-up revealed fluid recurrence in 27 (36%) patients after a mean follow-up of 17 days (range 2-285 days); 14 patients with successful pleurodesis died with a median survival of 61 days (range 13-174 days). Systemic treatment following pleurodesis and good apposition of the pleural surfaces during drainage were good prognostic factors. Despite reasonable-to-good adherence to the guideline, the number of successful pleurodeses was low. Better predictors of a good pleurodesis outcome are needed.

Basic helix-loop-helix transcription factor profiling of lung tumors shows aberrant expression of the proneural gene atonal homolog 1 (ATOH1, HATH1, MATH1) in neuroendocrine tumors.

Microarray-based expression profiling studies of lung adenocarcinomas have defined neuroendocrine subclasses with poor prognosis. As neuroendocrine development is regulated by members of the achaete-scute and atonal classes of basic helix-loop-helix (bHLH) transcription factors, we analyzed lung tumors for expression of these factors. Out of 13 bHLH genes tested, 4 genes, i.e., achaete-scute complex-like 1 (ASCL1, HASH1, Mash1), atonal homolog 1 (ATOH1, HATH1, MATH1), NEUROD4 (ATH-3, Atoh3, MATH-3) and neurogenic differentiation factor 1 (NEUROD1, NEUROD, BETA2), showed differential expression among lung tumors and absent or low expression in normal lung. As expected, tumors that have high levels of ASCL1 also express neuroendocrine markers, and we found that this is accompanied by increased levels of NEUROD1. In addition, we found ATOH1 expression in 9 (16%) out of 56 analyzed adenocarcinomas and these tumors showed neuroendocrine features as shown by dopa decarboxylase mRNA expression and immunostaining for neuroendocrine markers. ATOH1 expression as well as NEUROD4 was observed in small cell lung carcinoma (SCLC), a known neuroendocrine tumor. Since ATOH1 is not known to be involved in normal lung development, our results suggest that aberrant activation of ATOH1 leads to a neuroendocrine phenotype similar to what is observed for ASCL1 activation during normal neuroendocrine development and in lung malignancies. Our preliminary data indicate that patients with ATOH1-expressing adenocarcinomas might have a worse prognosis.

Pleural thickening in a construction worker: it is not always mesothelioma.

We describe the case of a 45-year-old man presenting with chest pain and pleural effusions. These symptoms were progressive over a period of three years, with pericardial involvement and respiratory insufficiency finally resulting in death. Despite repeated diagnostic procedures, a final diagnosis could only be made at autopsy. Multisystem foamy histiocyte infiltration suggested the diagnosis of Erdheim-Chester disease.

Acute pulmonary histoplasmosis from Ghana.

A male patient developed acute pulmonary histoplasmosis 2 weeks after bathing in the water falls of Wli, Ghana. Exposure to Histoplasma capsulatum was probably mediated through inhalation of an aerosol of water and guano from the large colony of fruit bats of the falls. More cases of acute pulmonary histoplasmosis can be expected.

Maintenance chemotherapy in small-cell lung cancer: long-term results of a randomized trial. European Organization for Research and Treatment of Cancer Lung Cancer Cooperative Group.

PURPOSE: The present study investigates the role of short chemotherapy (five cycles) versus prolonged (12 cycles) chemotherapy in small-cell lung cancer (SCLC). PATIENTS AND METHODS: Six hundred eighty-seven patients with SCLC were registered in a multicenter study to receive five cycles of chemotherapy consisting of cyclophosphamide 1 g/m2 on day 1, doxorubicin 45 mg/m2 on day 1, and etoposide 100 mg/m2 on days 1, 3 and 5 (CDE), every 3 weeks. Four hundred thirty-four nonprogressing patients after five cycles of chemotherapy were randomized either to receive seven further cycles of the same chemotherapy or to follow-up. RESULTS: The response rate of 585 assessable patients was 79%, with 36% attaining a complete response. Toxicity was mainly hematologic, with 16 toxic deaths (2.4% of all eligible patients), 13 of which were due to sepsis. Median survival time from registration of all patients was 326 days (396 and 267 days for limited and extensive disease, respectively) with 3.2% of patients alive at 5 years. No difference in survival between the two arms was observed, with the same number of 5-year survivors in both arms. The patients randomized to the maintenance arm had a progression-free survival (PFS) duration approximately 2 months longer than the patients randomized to follow-up (median of 177 days v 114 days from randomization; P = .0004). Among patients with a partial response who were randomized to receive maintenance chemotherapy, 12 achieved a complete response after 12 cycles. More patients in the follow-up arm than in the maintenance arm received subsequent treatment on progression and responded more frequently to that treatment. Twelve patients developed second malignancies (seven non-small-cell lung cancers). CONCLUSION: Prolonged chemotherapy does not offer a better chance of cure than short chemotherapy (five cycles) and does not prolong survival in patients with SCLC. Short, combination chemotherapy appears to be a reasonable choice for standard treatment of SCLC and for attempts to improve the cure rate of this disease.

Pharmacokinetics of paclitaxel and carboplatin in a dose-escalating and dose-sequencing study in patients with non-small-cell lung cancer. The European Cancer Centre.

PURPOSE: To investigate the pharmacokinetics and pharmacodynamics of paclitaxel (P) and carboplatin (C) in a sequence-finding and dose-escalating study in untreated non-small-cell lung cancer (NSCLC) patients. PATIENTS AND METHODS: Fifty-five chemotherapy-naive patients with NSCLC were entered onto the pharmacokinetic part of a large phase I trial in which P was administered as a 3-hour infusion at dosages of 100 to 250 mg/m2, and C over 30 minutes at dosages of 300 to 400 mg/m2. Patients were randomized for the sequence of administration, first C followed by P or vice versa. Each patient received the alternate sequence during the second and subsequent courses. RESULTS: The most important hematologic toxicity encountered-was neutropenia. Hematologic toxicity was not dependent on the sequence in which P and C were administered, but there was cumulative neutropenia. Nonhematologic toxicities consisted mainly of vomiting, myalgia, and arthralgia. No sequence-dependent pharmacokinetic interactions for the P area under the concentration-time curve (P-AUC), maximal plasma concentration (P-Cmax), or time above a threshold concentration of 0.1 mumol/L (P-T > or = 0.1 mumol/L) were observed. However, there was a significant difference for the metabolite 6 alpha-hydroxypaclitaxel AUC (6OHP-AUC). Higher 6OHP-AUCs were observed when C was administered before P. The mean plasma ultrafiltrate AUC of C (CpUF-AUC) at the dosage of 300 mg/m2 for the sequence C-->P was 3.52 mg/mL.min (range, 1.94 to 5.83) and 3.62 mg/mL.min for the sequence P-->C (range, 1.91 to 5.01), which is not significantly different (P = .55). Of 45 assessable patients, there were five major responders (three complete responders and two partial responders). Four of five responses occurred at dosages above dose level 4 (P 175 mg/m2 + C 300 mg/m2). The median survival duration was best correlated with the P dose (4.8 months for doses < 175 mg/m2 v 7.9 months for doses > or = 175 mg/m2, P = .07; P-T > or = 0.1 mumol/L, 4.8 months for < 15 hours v 8.2 months for > or = 15 hours, P = .06). CONCLUSION: There was no pharmacokinetic-sequence interaction between C and P in this study. A clear dose-response relation with respect to response rate and survival was observed. The pharmacokinetic parameter P-T > or = 0.1 mumol/L was related to improved survival in this study.

Molecular structure of the "low molecular weight antigen" of Toxoplasma gondii: a glucose alpha 1-4 N-acetylgalactosamine makes free glycosyl-phosphatidylinositols highly immunogenic.

Toxoplasma gondii is a ubiquitous parasitic protozoan causing congenital infection and severe encephalitis in the course of the acquired immunodeficiency syndrome. Glycosyl-phosphatidylinositols of T. gondii have been shown to be identical with the low molecular weight antigen which elicits an early immunoglobulin M immune response in humans. A detailed study of the structures of these glycolipid antigens was performed. Radiolabelled glycolipids were extensively analysed by chemical and exoglycosidase treatments in combination with high pH anion-exchange chromatography, gel-filtration and lectin affinity chromatography. In addition, carbohydrate fragments prepared and purified from bulk preparations of unlabelled glycolipids by high performance liquid chromatography were subjected to two-dimensional 1H nuclear magnetic resonance spectroscopy, fast-atom bombardment-mass spectrometry, and methylation linkage analysis in order to elucidate the structure of T. gondii GPIs. The following structures were identified: (ethanolamine-PO4)-Man alpha 1-2Man alpha 1-6(GalNAc beta 1-4)Man alpha 1-4GlcN alpha-inositol-PO4-lipid and the novel structure (ethanolamine-PO4)-Man alpha 1-2Man alpha 1-6(Glc alpha 1-4GalNAc beta 1-4)Man alpha 1-4 GlcN alpha-inositol-PO4-lipid both with and without terminal ethanolamine phosphate. Evidence is provided, that only T. gondii GPIs bearing the unique glucose-N-acetylgalactosamine side branch are immunogenic in humans and that this structure is widely distributed among T. gondii isolates. Monoclonal antibodies have been characterized to recognize structures with different degrees of side-chain modification. We suggest that these reagents in combination with recently devised techniques for insertional mutagenesis in T. gondii should greatly facilitate the cloning of genes essential for GPI side-chain modification.

Adrenergic activity and peripheral hemodynamics in relation to sodium sensitivity in patients with essential hypertension.

In 25 outpatients with essential hypertension, sodium sensitivity, defined as the difference in mean arterial pressure (delta MAP) between 2 weeks of high-sodium (300 mmol per day) and 2 weeks of low-sodium (LS) intake (50-100 mmol per day), was studied in relation to the plasma norepinephrine (NE) level, NE release, and pressor response to intravenous NE. In addition, forearm blood flow (FBF) was measured by plethysmography. There were two control periods of regular sodium intake, one of 4 weeks' duration at the beginning of the study and one of 2 weeks' duration at the end. The delta MAP ranged from +18 to -8 mm Hg. The eight patients in whom delta MAP was greater than 10 mm Hg were regarded as salt-sensitive. When compared with salt-insensitive subjects, salt-sensitive patients had higher plasma NE levels in the control period (p less than 0.05) and after 2 weeks of HS intake (p less than 0.01). Sodium sensitivity was directly related to the change in plasma NE between the HS and LS periods (p less than 0.001). The NE release decreased in salt-insensitive subjects whereas it increased in salt-sensitive patients between the LS and HS periods. Changes in NE release were directly related to sodium sensitivity (p less than 0.05). The pressor response to NE was not significantly influenced by changes in sodium intake. The FBF fell in salt-sensitive patients and increased in salt-insensitive subjects between the LS and HS periods. Sodium sensitivity was directly related to the change in forearm vascular resistance (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Feasibility of escalating daily doses of cisplatin in combination with accelerated radiotherapy in non-small cell lung cancer.

The aim of this study was to determine whether it is feasible to reduce the overall treatment time from 7 to 4 weeks in patients with non-small cell lung cancer (NSCLC) receiving radiotherapy with cisplatin. This follows an EORTC phase III randomised trial (08844) in which cisplatin given before each radiation dose resulted in improved local control and survival, but which had a relatively long treatment period of 7 weeks [Schaake-Koning et al., N Engl J Med 1992, 326, 524-530]. 38 patients with confirmed NSCLC (2 stage I, 1 stage II, 18 stage IIIA, 17 stage IIIB) received a total tumour dose of 55 Gy/20 fractions/26 days, from January 1992 to March 1994. Daily fractions of 2 Gy (5 times/week) were given to the macroscopic tumour and the non-involved adjacent lymph node areas. During the same session, a dose of 0.75 Gy was given to the macroscopic tumour (simultaneous boost). Cisplatin 6 mg/m2 was administered 1-2 h before each fraction, in an escalating total dose, during week 1 in 3 patients, during weeks 1 and 2 in 6 patients, during weeks 1, 2 and 3 in 5 patients and during the whole treatment in 24 patients. 38 patients were evaluable for acute side-effects (WHO). Maximal therapy-related toxicity (WHO) was grade 3 (nausea/vomiting in 2 patients, oesophagitis in 3 patients, dyspnoea in 3 patients, cough in 1 patient). Late side-effects were evaluated in 34 patients. There was grade 2 oesophagitis in 2 patients; grade 3 toxicity in 8 patients (tiredness in 3 patients, dyspnoea in 3 patients, oesophagitis in 2 patients); grade 4 toxicity in 4 patients (dyspnoea in 3 patients, cough in 1 patient). Pulmonary fibrosis grade 3 occurred in 4 and grade 4 in 6 patients. One patient developed a severe (grade 3) radiation pneumonitis. The low incidence of acute and late side-effects with this treatment, combining daily administration of 6 mg cisplatin with radical radiotherapy using a simultaneous boost technique, indicates that escalation of the radiation dose seems feasible.

Toxicity of high-dose radiotherapy combined with daily cisplatin in non-small cell lung cancer: results of the EORTC 08912 phase I/II study. European Organization for Research and Treatment of Cancer.

The purpose of this work was to study the feasibility of concurrent chemoradiation in patients with inoperable non-small cell lung cancer (NSCLC). 40 patients with inoperable NSCLC were treated with escalating doses of radiotherapy and cisplatin (cDDP). The radiation dose was increased step by step from 60.5 to 66 Gy in daily fractions of 2.75 Gy. Chemotherapy was also increased step by step from 20 to 24 daily doses of cDDP 6 mg/m(2) and given concurrently with radiotherapy. A dose of 40 Gy/2 Gy/20 fractions (fx) was given to the EPTV (elective planning target volume) which included the gross tumour volume with a margin of 2 cm and part of or the entire mediastinum. During each session a boost dose of 0.75 Gy was given simultaneously to the BPTV (boost planning target volume), which encompassed the GTV (gross tumour volume) with a margin of 1 cm, for the first 20 fx, so the total dose to the tumour was 55 Gy. Cisplatin 6 mg/m(2) was given 1 h prior to radiotherapy at each fraction. From then on the dose of radiation to the BPTV and the dose of cDDP were increased step by step. In group I the BPTV was irradiated with two extra fractions of 2.75 Gy to a total dose of 60. 5 Gy without cDDP. In group II the same total dose of 60.5 Gy was given but the last two fractions were combined with cDDP. In group III four extra fractions of 2.75 Gy were given to the BPTV to a total dose of 66 Gy, only two of these fractions combined with cDDP. Finally, in group IV a total dose of 66 Gy was given in 24 fractions, all fractions combined with cDDP. All patients were planned by means of a CT-based conformal treatment planning. The maximal length of the oesophagus receiving >/=60.5 Gy was 11 cm. 40 patients were evaluable for acute and late toxicity and for survival. Acute toxicity grade >/=3 (common toxicity criteria, CTC) was rarely observed; nausea/vomiting in 3 patients (8%), leucopenia in 2 patients (5%), thrombocytopenia in 2 patients (5%), whilst 2 patients (5%) suffered from severe weight loss. Late side-effects (European Organization for Research and Treatment of Cancer/Radiation Therapy Oncology Group, EORTC/RTOG) were: oesophageal toxicity >/=grade 3 in 2 patients (5%) and radiation pneumonitis grades 1 (3%) and 2 (3%) in 1 patient each. Overall actuarial 1- and 2-year survival was 53% and 40%, respectively. The 1- and 2-year local disease-free interval was 65% and 58% respectively. Radiotherapy at a dose of 66 Gy/2.75 Gy/24 fx combined with daily cDDP 6 mg/m(2) given over 5 weeks is feasible and results in a good local disease-free interval and a good survival rate. This treatment schedule is at present being tested as one of the two treatment arms of EORTC phase III study protocol 08972/22973.

Preliminary results of two dose-finding studies of paclitaxel (Taxol) and carboplatin in non-small cell lung and ovarian cancers: a European Cancer Centre effort.

Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) given as a 24-hour infusion, and carboplatin have activity in advanced non-small cell lung cancer (NSCLC) and ovarian cancer. Two dose-finding studies were initiated to identify the optimal doses for the paclitaxel/carboplatin combination when paclitaxel is given in a 3-hour infusion. The fact that the pharmacologic interaction between paclitaxel and cisplatin increases the toxicity of paclitaxel when cisplatin is given before it also prompted an investigation of the influence of drug sequence on toxicity and pharmacokinetics in the NSCLC trial. Thirty-three patients with advanced NSCLC and 11 with advanced ovarian cancer previously untreated by chemotherapy have been enrolled to date. In the NSCLC trial escalating doses of paclitaxel were given in combination with a fixed carboplatin dose of 300 mg/m2, while both drugs were escalated in the ovarian cancer study. In both studies paclitaxel was infused over 3 hours and carboplatin over 30 minutes, and cycles were repeated every 4 weeks. The most frequent side effect has been neutropenia, although this did not result in any infectious episodes. Alopecia and mild emesis also have been frequently encountered. Mild skin reactions have been reported in a few patients. Bone pain and myalgia occur more frequently at the highest paclitaxel doses. No difference in toxicity has been observed thus far between the two drug sequences in the NSCLC study. Both studies are still accruing patients as the maximum tolerated doses of paclitaxel in combination with carboplatin have not yet been reached (carboplatin 300 mg/m2 with paclitaxel 175 mg/m2 in the NSCLC study; carboplatin 400 mg/m2 with paclitaxel 150 mg/m2 in the ovarian cancer study). An investigation of maximum tolerated doses with granulocyte colony-stimulating factor support is planned thereafter.

Dose-finding and sequencing study of paclitaxel and carboplatin in non-small cell lung cancer.

A dose-finding study was set up to identify the optimal dose of the combination of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) and carboplatin for phase II studies in patients with advanced chemotherapy-naive non-small cell lung cancer (NSCLC). The influence of drug sequence on the toxicity and pharmacokinetics of both agents was also assessed. To develop an ambulatory regimen for palliation of advanced NSCLC, paclitaxel was infused over 3 hours with standard premedication and carboplatin over 30 minutes. Cycles were repeated every 4 weeks. At each dose level, at least six patients were randomized to receive either paclitaxel followed by carboplatin or the reverse sequence. In the second and following cycles the alternate sequence was administered. The pharmacokinetics of both paclitaxel and carboplatin were compared in the first two cycles in at least two patients per dose level. Sixty-two patients have been entered in this study. Paclitaxel was increased from 100 mg/m2 in 25 mg/m2 increments up to a maximum of 225 mg/m2 combined with a fixed carboplatin dose (300 mg/m2). Thereafter, the drug doses were increased to a maximum of 400 mg/m2 carboplatin and 250 mg/m2 paclitaxel. In 243 cycles, the most frequent side effects were neutropenia, alopecia, and mild emesis. Only one patient developed a major hypersensitivity reaction to paclitaxel. Bone pain, myalgia, and peripheral neurotoxicity occurred more frequently at paclitaxel doses above 200 mg/m2. No significant differences in toxicity or in the pharmacokinetics of either drug were observed between the two drug sequences. The pharmacokinetics of paclitaxel were nonlinear and consistent with saturation. At the highest paclitaxel dose (250 mg/m2 with carboplatin 350 mg/m2) a toxic death due to severe leukopenia, thrombocytopenia, and hemorrhage occurred. Safe doses for phase II trials in untreated NSCLC are 200 mg/m2 paclitaxel with 300 mg/m2 carboplatin. Of 50 evaluable patients, five of the six major responses were observed at paclitaxel doses of 175 mg/m2 and above, which suggests a dose-response relationship for paclitaxel in NSCLC.

Clinical pharmacology of carboplatin administered in combination with paclitaxel.

The clinical pharmacology of carboplatin (C) administered with paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) (P) was investigated in two phase I studies undertaken in 83 previously untreated patients with either non-small cell lung cancer or ovarian cancer. Carboplatin was administered over 30 minutes and paclitaxel over 3 hours. Both agents were given every 4 weeks. Non-small cell lung cancer patients were randomized to two administration sequences, either carboplatin followed by paclitaxel (C-->P) or the reverse (P-->C). Each patient received the alternate sequence during the second and subsequent courses. Ovarian cancer patients uniformly received paclitaxel before carboplatin. Platinum concentrations in plasma ultrafiltrate were measured via flameless atomic absorption spectrometry, and 122 concentration-time curves were obtained. For non-small cell lung cancer patients, the mean area under the concentration-time curve (AUC) per 300 mg/m2 carboplatin was 3.52 mg/mL x min (range, 1.94 to 5.83) for the sequence C-->P and 3.62 mg/mL x min (range, 1.91 to 5.01) for the sequence P-->C. No sequence-dependent effect was observed (P > .5). For ovarian cancer patients, the mean AUC per 300 mg/m2 carboplatin was 3.83 mg/mL x min (range, 2.72 to 6.10), showing no difference when compared with data derived from non-small cell lung cancer patients (P = .13). In addition, the carboplatin AUC was not influenced by increasing paclitaxel doses from 100 to 250 mg/m2. Neutropenia was the principal toxicity, and anemia was frequent. However, there was a striking lack of thrombocytopenia. Modeling of the relationship between the carboplatin AUC and the decrease in platelets revealed a 50% decrease in platelets at a carboplatin AUC (AUC50) of 6.3 mg/mL x min. This contrasts with historical data documenting a carboplatin AUC50 of 4.0 mg/mL x min. Our findings suggest that there is a considerable interaction of both drugs at the cellular level, with at least an additive effect of carboplatin on the main hematologic toxicity of paclitaxel (ie, neutropenia). There is also a protective effect exerted by paclitaxel on carboplatin-related toxicity (ie, thrombocytopenia). The clear protective effect of paclitaxel in this combination suggests that it is possible to reduce the dose interval to 3 weeks. Studies are in progress to test this hypothesis and to investigate the underlying pharmacologic interactions.

Sodium sensitivity in essential hypertension: role of the renin-angiotensin-aldosterone system and predictive value of an intravenous frusemide test.

In order to determine factors contributing to sodium induced changes of blood pressure, 20 patients with essential hypertension were studied when on their regular sodium intake and after two weeks of a low sodium diet (50 mmol daily) and two weeks of a high sodium diet (300 mmol daily). There were two periods of regular sodium intake, one of four weeks at the beginning and one of two weeks at the end of the study. The change in mean arterial pressure between the high and low salt diets (delta MAP) was regarded as a measure of sodium sensitivity, and was directly correlated with age and initial blood pressure. Compared with non-responders, responders (delta MAP 10 mmHg or more) showed a lesser activation of the renin-angiotensin-aldosterone system during the low salt period. The response to the administration of intravenous frusemide was not helpful in predicting sodium sensitivity. A significant but relatively small (4.2 mmHg) reduction in MAP was obtained during low salt period compared with the first period of regular sodium intake. The data suggest that moderate dietary sodium restriction can help to reduce the blood pressure of the relatively older patient with hypertension.

Excretion of urokallikrein in renal transplant patients. Relation to graft rejection, renal function, and blood pressure.

The relation between urinary kallikrein excretion ( Ukal ) and rejection, graft function, and blood pressure was studied in 45 renal transplant recipients. Ukal was assayed by means of an enzymatic (amidolytic) method, as well as with a specific radioimmunoassay. In a group of 10 patients studied longitudinally from the day of transplantation till day 35 +/- 3, an increase in urinary amidolytic activity without a concomitant increase in kallikrein antigen excretion was found to precede 11 out of 14 rejection episodes. This increased amidolytic activity generally persisted for several days. It was demonstrated by chromatography using an immunoadsorbent column of antiurokallikrein that the rejection-associated esterase, or esterases, differed from urokallikrein . In 35 outpatient recipients with stable graft function, Ukal excretion was decreased compared with that of healthy controls (42 +/- 7.5 vs. 107.5 +/- 7.3 micrograms/24 hr by radioimmunoassay and 0.70 +/- 0.08 vs. 1.10 +/- 0.07 U/24 hr, using the amidolytic method); for these patients a significant correlation between Ukal excretion and creatinine clearance was found (P less than 0.02). Both in transplant recipients and in controls there was a close correlation between the results of the two Ukal assays (P less than 0.001). No significant relation between Ukal excretion and blood pressure was found, either for patients or for controls. It is concluded that acute graft rejection is accompanied by an increased excretion of nonurokallikrein esterase(s). The lower Ukal excretion in patients with stable renal function seems to be related to their reduced renal function. No relation between Ukal excretion and blood pressure levels was found.