Right ventricle dimensions and function in response to acute hypoxia in healthy human subjects.

AIM: Acute hypoxia produces acute vasoconstriction in the pulmonary circulation with consequences on right ventricular (RV) structure and function. Previous investigations in healthy humans have been restricted to measurements after altitude acclimatization or were interrupted by normoxia. We hypothesized that immediate changes in RV dimensions in healthy subjects in response to normobaric hypoxia differ without the aforementioned constraints. METHODS: Transthoracic echocardiography was performed in 35 young, healthy subjects exposed to 11% oxygen, as well as six controls under sham hypoxia (20.6% oxygen, single blind) first at normoxia and after 30, 60, 100, 150 min of hypoxia or normoxia respectively. A subgroup of 15 subjects continued with 3-min cycling exercise in hypoxia with subsequent evaluation followed by an assessment 1 min at rest while breathing 4 L min-1 oxygen. RESULTS: During hypoxia, there was a significant linear increase of all RV dimensions (RVD1 + 29 mm, RVD2 + 42 mm, RVD3 + 41 mm, RVOT + 13 mm, RVEDA + 18 mm, P < 0.01) in the exposure group vs. the control group. In response to hypoxia, right ventricular systolic pressure (RVSP) showed a modest increase in hypoxia at rest (+7.3 mmHg, P < 0.01) and increased further with physical effort (+11.8 mmHg, P < 0.01). After 1 min of oxygen at rest, it fell by 50% of the maximum increase. CONCLUSION: Acute changes in RV morphology occur quickly after exposure to normobaric hypoxia. The changes were out of proportion to a relatively low-estimated increase in pulmonary pressure, indicating direct effects on RV structure. The results in healthy subjects are basis for future clinically oriented interventional studies in normobaric hypoxia.

The (-765 G→C) promoter variant of the COX-2/PTGS2 gene is associated with a lower risk for end-stage hip and knee osteoarthritis.

BACKGROUND: Functional polymorphisms in genes of proinflammatory signalling cascades may contribute to the genetic risk of osteoarthritis (OA). OBJECTIVE: To examine a possible association between end-stage OA of the hip and knee joint and a known single nucleotide polymorphism (SNP) of the COX-2 gene promoter. METHODS: The SNP -765 G→C (rs20417) of the COX-2 gene promoter was genotyped by pyrosequencing in 531 (320 women/211 men) patients with OA from the Ulm Osteoarthritis Study and 400 (200 women/200 men) regional controls from the south-west of Germany. RESULTS: In the whole study population the C allele was associated with a lower risk (per allele OR 0.57; 95% CI 0.43 to 0.75, p<0.0001) and the G allele with a higher risk for end-stage OA. Analysis of subgroups confirmed this result for primary, bilateral, hip and knee OA. CONCLUSION: The promoter polymorphism rs20417 of the COX-2 gene contributes to the genetic risk for end-stage hip and knee OA.

Clinical characterisation of 29 neurofibromatosis type-1 patients with molecularly ascertained 1.4 Mb type-1 NF1 deletions.

BACKGROUND: Large deletions of the NF1 gene region occur in approximately 5% of patients with neurofibromatosis type-1 (NF1) and are associated with particularly severe manifestations of the disease. However, until now, the genotype-phenotype relationship has not been comprehensively studied in patients harbouring large NF1 gene deletions of comparable extent (giving rise to haploinsufficiency of the same genes). METHOD: We have performed the most comprehensive clinical/neuropsychological characterisation so far undertaken in NF1 deletion patients, involving 29 patients with precisely determined type-1 NF1 (1.4 Mb) deletions. RESULTS: Novel clinical features found to be associated with type-1 NF1 deletions included pes cavus (17% of patients), bone cysts (50%), attention deficit (73%), muscular hypotonia (45%) and speech difficulties (48%). Type-1 NF1 deletions were found to be disproportionately associated with facial dysmorphic features (90% of patients), tall stature (46%), large hands and feet (46%), scoliosis (43%), joint hyperflexibility (72%), delayed cognitive development and/or learning disabilities (93%) and mental retardation (IQ<70; 38%), as compared with the general NF1 patient population. Significantly increased frequencies (relative to the general NF1 population) of plexiform neurofibromas (76%), subcutaneous neurofibromas (76%), spinal neurofibromas (64%) and MPNSTs (21%) were also noted in the type-1 deletion patients. Further, 50% of the adult patients exhibited a very high burden of cutaneous neurofibromas (N>or=1000). CONCLUSION: These findings emphasise the importance of deletion analysis in NF1 since frequent monitoring of tumour presence and growth could potentiate early surgical intervention thereby improving patient survival.

Sample volume positioning in colour-coded Doppler myocardial imaging: effect of systolic and diastolic tracking.

To date, Doppler myocardial imaging (DMI) is no longer an intriguing new research tool only, but is rather on the verge of becoming a routinely used diagnostic method in adult and pediatric cardiology. Clinical studies have proven its diagnostic relevance for global left and right ventricular function. Concerns about reliability and reproducibility of DMI functional analysis, however, rely on lacking standards for the acquisition and analysis of DMI parameters. This study focuses on the effect of sample volume positioning during the cardiac cycle on the absolute myocardial velocities. Our hypothesis was that systolic sample volume placement leads to altered diastolic measurements, and diastolic placement vice versa to altered systolic measurements, when compared with continuous systolic and diastolic tracking. The effect of tracking on intra- and interobserver variability was a second endpoint of the study. Twenty healthy women underwent color-coded Doppler myocardial imaging. Clips of three heart cycles were stored in digital format for off-line analysis, administering sector angles of approximately 30 degrees and a mean frame rate of 280 frames per second. Using the Echopac software (GE, Germany), the sample volume was positioned immediately below the atrioventricular valvar annulus within the basal segments of the right and left ventricular free wall and the interventricular septum. Three conditions were investigated: conventional end-systolic or end-diastolic placement of the Doppler probe, or continuous tracking to the ideal position during systole or diastole. Descriptive statistics, intra and interobserver variabilities and Bland-Altman analyses were performed. Tracking revealed higher values of early diastolic myocardial velocities compared with measurements during systolic sample volume placement only, and higher systolic myocardial velocities, preejection acceleration and late diastolic myocardial velocities using diastolic sample volume placement. Inter and intraobserver reproducibility improved remarkably with the new procedure with the exception of isovolumic acceleration (IVA), which could not be reproduced satisfactorily at all. In summary, tracking is a promising method that helps to improve reproducibility of DMI-derived myocardial velocities. It helps to minimize the effect of changing myocardial velocities during the natural longitudinal cardiac movement, and should be considered as standard method during DMI.

[Prospective evaluation of prostate cancer screening in men with a family history of the disease]. / Prospektive Evaluierung der Prostatakarzinomfrüherkennung bei Männern mit familiärer Disposition.

BACKGROUND: Family history is one of the strongest risk factors for prostate cancer. In this prospective study we evaluated the results of prostate cancer screening performed in healthy brothers of prostate cancer patients. The detection rate of prostate cancer and the positive predictive value of the examinations were determined. MATERIAL AND METHODS: The study population comprised 513 healthy men who were 38-75 years of age (median 62.0 years). Of these men, 268 having only one affected brother with prostate cancer were assigned to the sporadic group, and 245 probands having 2-10 affected relatives were assigned to the familial group. An abnormal PSA and/or a pathological digital rectal examination (DRE) was noted in 17.5% of familial (43/245) and 15.8% of sporadic probands (35/268). A biopsy of the prostate was performed in 60.5% of familial (26/43) and 71.4% of sporadic (25/35) men with pathological findings. RESULTS: Prostate cancer was found in 15 of 26 familial (57.7%) and 16 of 25 sporadic (64.0%) probands by prostate biopsy. The overall detection rate was 6.0% (31/513). CONCLUSION: Due to an increased prevalence the detection rate of prostate cancer and the positive predictive value of PSA and/or DRE are higher in men with a family history as expected in an unselected population. Our data suggest that in predisposed men prostate cancer screening should be recommended early. Furthermore an early indication for prostate biopsy is necessary. This recommendation should also be applied if only one first-degree relative has prostate cancer.

Hydrolysis of casein accelerates gastrointestinal transit via reduction of opioid receptor agonists released from casein in rats.

BACKGROUND: Protein hydrolysate accelerates gastrointestinal transit (GIT) and feeding advancement in preterm infants compared to native protein. In rat pups, opioid receptor agonists released from casein during digestion such as beta-casomorphins slow down GIT. We hypothesized that hydrolysis of casein reduces the opioid activity released during digestion thereby accelerating GIT compared to native casein. OBJECTIVE: The aim of the present study was to investigate whether casein hydrolysate accelerates GIT compared to native casein and whether pretreatment with naloxone, an opioid receptor blocker, abolishes this difference in rat pups. METHODS: In a randomized controlled trial following a 2 x 2 factorial design, 216 female Wistar rat pups were fed with pellets based on hydrolyzed or native casein. After pretreatment with naloxone or normal saline, carmine red was administered by oro-gastric gavage as a tracer for GIT velocity measurement. Four hours later the animals were sacrificed, their intestine was removed and the length of the colon from the cecocolonic junction to the anus was measured. GIT was recorded as percentage of the total colonic length (percentage of colonic transit) passed by carmine red. Data were given as mean +/- SD. RESULTS: GIT was significantly higher with hydrolyzed casein compared to native casein formula (77.4 +/- 17 and 51.2 +/- 20%), but there was no difference after naloxone pretreatment (77.1 +/- 16 and 76.5 +/- 17%). DISCUSSION: The present data suggest that hydrolysis of casein accelerates GIT via reduction of opioid activity released during digestion. Further studies are required to investigate to which extent these rat pub data apply to preterm infants.

The abdominal circumference to weight ratio increases with decreasing body weight in preterm infants.

UNLABELLED: Abdominal distension is one of the major clinical indications to withhold feedings in preterm infants. The abdominal circumference (AC) was measured in 42 premature infants on full enteral nutrition in order to establish reference values. AC decreased linearly (r2 = 0.83) with decreasing weight. However, the AC to weight ratio increased substantially (hyperbolically) with decreasing weight. CONCLUSION: The increased AC to weight ratio may be misinterpreted as pathological abdominal distension in the clinical assessment of preterm infants on full enteral nutrition.

[Quality of life after surgical treatment of osteitis]. / Lebensqualität nach operativer Osteitisbehandlung.

Although many studies have measured the functional outcome after surgical treatment of osteomyelitis, there have been few published attempts to evaluate the long-term quality of life. We therefore undertook this study to assess the quality of life in a large patient population after operative treatment for this condition. All patients who underwent operative treatment for osteomyelitis from 1993 until 1997 at our institution were included in the study. The patients were assessed with a questionnaire which contained the SF-36 (German version) and questions about the activity and history of the illness. The result was compared to the data set from a standard population. Of the 502 patients, 345 (69%) returned questionnaires for evaluation. The infection was inactive in 301 (88%). Compared to a standard population, the investigated patients showed a significant reduction in their overall psychological well being and physical functional capacities. Surgical treatment was able to inactivate the infection in 88% of the patients. Because of persistent deficits, the psychological well being and physical functional capacities are reduced compared to a standard population.

Guidelines for the intramuscular positioning of EMG electrodes in the semispinalis capitis and cervicis muscles.

The objective of the study was to establish guidelines for the application of fine-wire or needle electrodes in the semispinalis cervicis and semispinalis capitis muscles. First of all, measured data for the puncture angle and puncture depth of each muscle were determined in CT scans. Using a regression approach, a model relation of these data with the neck circumference was established. This made it possible to accurately determine the puncture angle and puncture depth on the basis of the known neck circumference. In a further step, the neck muscles of seven human cadavers were punctured with wires in order to check the workability of these guidelines. At the same time, the wires' positions in relation to important structures (nerves, vessels) were studied. Both muscles can be punctured with a high degree of reliability. However, when puncturing the semispinalis cervicis muscle, one has to pass through a layer that contains vessels, nevertheless the risk of injury is regarded as very small. The technique enables intramuscular EMG measurements of the two muscles in manifold clinical problems.

Hydrolysed protein accelerates the gastrointestinal transport of formula in preterm infants.

UNLABELLED: Vomiting, large gastric residuals and abdominal distension are common in very immature infants on formula feeding. The present trial investigated whether a protein hydrolysate formula reduces the gastrointestinal transit time in preterm infants. Fifteen preterm infants (median gestational age 29 (24-32) wk, birthweight 1241 (660-1900) g, postnatal age 18 (5-54) d) on full enteral feeds (>150 ml/kg*d) were enrolled. It was hypothesized that the gastrointestinal transit time is at least 2 h shorter when protein hydrolysate formula is fed compared with standard preterm formula. In a randomized cross-over design study, each formula was fed for 5 d. On days 4 and 9 the gastrointestinal transit time was estimated using carmine red. The protein hydrolysate formula had a markedly shorter gastrointestinal transit time (9.8 h) than the standard formula (19 h) (p = 0.0022, two-sided Mann-Whitney U test). CONCLUSION: The hydrolysate protein formula accelerated gastrointestinal transit of milk and stools, but whether hydrolysate formulas enable a more rapid establishment of full enteral feeding in preterm infants needs to be investigated.

A quotient of independent measurements as outcome. A statistical method to compare groups in biological experiments.

The methodology in this paper was proposed to analyze biological data. The variable of interest, W, was a quotient of measurements; W: = X/(Y.Z). The peculiar problem was that X, Y, and Z could only be determined in three independent units of observation which were destroyed in the course of each measurement. A test statistic for the comparison of two treatments in W is proposed which is based on robust measures of location and dispersion in order to account for outliers in the data. Simulations showed that the test statistic proposed is approximately normally distributed, even for small sample sizes.

Hemoglobin A1c and body mass index in children and adolescents with IDDM. An observational study from 1976-1995.

In adult patients with type 1 diabetes good metabolic control was associated with an undesired weight gain. In the present report the possible association of HbA1c and body mass index (BMI) in children and adolescents with type 1 diabetes (IDDM) was investigated in a long-term retrospective study from 1976 to 1995. Further, the relationship between BMI on one hand and age, gender, duration of IDDM, the number of units of insulin used and the number of injections per day on the other hand were considered. Statistical analysis was performed using repeated measurements analyses of variance. The 208 girls and 201 boys were 5-17 years old and had diabetes for beyond one year. For analysis 2512 data sets, in part measurements on the same patient in the course of the disease, were available. In various statistical models, the results show that age, gender, the daily amount of insulin, and the HbA1c level (p<0.001-0.005) were associated with the BMI. Extremely high HbA1c levels coincided with a remarkably low BMI. Hence, in children and adolescents with IDDM it may be difficult to achieve a constantly good metabolic control accompanied by a normal body weight.

Evaluation of three risk scores to predict postoperative nausea and vomiting.

BACKGROUND: So far there are three different scores to predict postoperative vomiting (PV: Apfel et al., 1998) or postoperative nausea and vomiting (PONV: Koivuranta et al., 1997; Palazzo and Evans, 1993). All three scores used logistic regression analysis to identify and create weights for the risk factors for PV or PONV. In short, these were sex, age, history of previous PONV, motion sickness, duration of anaesthesia, and use of postoperative opioids. However, an external evaluation and a comparison of these scores has not been performed so far. METHODS: Patients undergoing a variety of surgical procedures under general anaesthesia were studied prospectively. Preoperatively, they completed a questionnaire concerning potential risk factors for the occurrence of PV or PONV implemented in the three risk scores. Balanced anaesthesia (induction agent, nondepolarising neuromuscular blocker, opioid, and inhalation agent in nitrous oxide/oxygen) was performed. No intravenous anaesthesia or any antiemetic prophylaxis was applied. Postoperatively, the patients were observed in the recovery room for the occurrence of PV and PONV and were visited twice on the ward within the 24-h observation period. Both the patients and the nursing staff were asked whether PV or PONV was present. The severity of PONV was categorised using a standardised scoring algorithm. A total of 1,444 patients was finally included into the analysis. Using information of the predicted risk for the individual patients and the actual occurrence of PV or PONV, Receiver Operator Characteristics (ROC-curves) were drawn. The area under each ROC-curve was calculated as a means of the predictive properties of each score and was compared for statistical differences. RESULTS: For prediction of PONV (any severity) the AUC-values (AUC=area under the curve) and the corresponding 95%-confidence intervals were: Apfel: 0.70 (0.67-0.72); Koivuranta: 0.71 (0.69-0.73); Palazzo: 0.68 (0.65-0.70). For prediction of PV: Apfel: 0.73 (0.71-0.75); Koivuranta: 0.73 (0.70-0.75); Palazzo: 0.68 (0.65-0.70). Thus, all three scores appeared to have a moderate accuracy as measured by the AUC. The score of Koivuranta predicts PONV (P=0.007) and also PV (P=0.002) significantly better than Palazzo's score. Furthermore, for predicting of PV the score of Apfel was also superior to Palazzo's score (P=0.005). All three scores predict PV with the same accuracy as PONV. CONCLUSION: The occurrence of PV and PONV in patients undergoing surgery under balanced anaesthesia can be predicted with moderate but acceptable accuracy using one of the available risk scores, regardless of local surgical or anaesthesiological circumstances. For clinical practice, we recommend the score published by Koivuranta, since its calculation is very simple.

Correlation of positive RT-PCR for tyrosinase in peripheral blood of malignant melanoma patients with clinical stage, survival and other risk factors.

The clinical value of the reverse transcription polymerase chain reaction (RT-PCR) assay for tyrosinase in peripheral blood of melanoma patients is still under debate. A total of 212 blood samples from 212 melanoma patients in all clinical stages (AJCC) were examined. Erythrocytes were lysed prior to RNA extraction by phenol precipitation from 2.7 ml of blood. cDNA for tyrosinase PCR was synthesized using random hexamers. Positive tyrosinase RT-PCR results were obtained in 11% of 106 stage I patients, 18% of 56 stage II patients, 31% of 26 stage III patients and 67% of 24 stage IV patients. After a median follow-up of 36 months (range 26-41), stage III patients with positive RT-PCR for tyrosinase had a shortened disease-free interval as compared to negative patients (P < 0.01). In stage IV patients, median overall survival was 8 months in case of a positive RT-PCR in contrast to 12 months in case of a negative test. While univariate analysis showed sex and primary tumour location associated with positive RT-PCR, multiple regression analysis revealed clinical stage and detection of tyrosinase transcripts in peripheral blood as best prognostic factors. Hazard ratios for disease-free survival were 19.7 (confidence interval (CI) 8.53-45.5, P = 0.0001) for metastatic vs primary disease and 2.96 (CI 1.49-5.89, P = 0.002) for positive vs negative tyrosinase RT-PCR. The corresponding hazard ratios for overall survival were 97.0 (CI 12.7-741, P = 0.0001) and 4.33 (CI 1.69-11.1, P= 0.002). Our results emphasize the importance of tyrosinase RT-PCR testing in peripheral blood.

The procedure of new drug application and the philosophy of critical rationalism or the limits of quality assurance with good clinical practice.

K.R. Popper's philosophy of critical rationalism is concerned with the detection and removal of error. Fundamental contradictions exist between Popper's theory of knowledge and the present-day practice of the clinical investigation of new drugs. Currently, the public authorities concerned with the licensing of drugs pass judgment on trials, which are closely linked by the one-sponsor problem: the assertions made by the sponsor are not independently confirmed. This lack leads to excessive documentation and to costly monitoring and auditing, which are intended to ensure the credibility of results. In Popper's view, confirmatory trials, independent of the sponsor and supervised by the regulatory bodies, would be a better way to achieve reliable knowledge. The consequence would, among other things, be a reorganization of phase III of the clinical investigation of new drugs by dividing it into independent parts, one under the control of the sponsor and one under the control of the public authority. The implementation of this suggestion would lead to a more scientific manner of dealing with new drugs and to savings in terms of unproductive measures during the application process.

Randomized comparison of high-frequency ventilation with high-rate intermittent positive pressure ventilation in preterm infants with respiratory failure.

OBJECTIVE: In a randomized, controlled, multicenter trial, we tested the hypothesis that high-frequency ventilation (HFV) with a high lung volume strategy results in fewer treatment failures than intermittent positive pressure ventilation (IPPV) with high rates and low peak inspiratory pressures. STUDY DESIGN: Infants with a gestational age between >/=24 weeks and <30 weeks, requiring mechanical ventilation within 6 hours of birth, were randomly assigned to receive either IPPV or HFV until 240 hours after randomization, extubation, or meeting treatment failure criteria. Treatment failure, the primary end point, was determined when air leaks, an oxygenation index >35 to 45 (depending on gestational age), death, or chronic lung disease occurred. Chronic lung disease was defined as persistent requirement of mechanical ventilation, continuous positive airway pressure, or supplemental oxygen at a postmenstrual age of 36 weeks. Secondary end points included the incidence of intracranial hemorrhage. RESULTS: The third scheduled interim analysis led to termination of the trial after recruitment of 284 infants. Treatment failure criteria were met by 46% of infants receiving IPPV and 54% of infants receiving HFV (1-tailed primary hypothesis, P =.92; 2-tailed chi2 test, P =.15). Air leaks occurred in 31% and 42% (P =.042), CLD in 23% and 25%, and grade 3-4 intracranial hemorrhage in 13% and 14% of IPPV-treated and HFV-treated patients, respectively. The mortality rate before discharge was 10% in both groups. CONCLUSION: HFV with a high lung volume strategy did not cause less lung injury in preterm infants than IPPV with a high rate and low peak inspiratory pressures.

Cardiac changes in fetuses secondary to immune hemolytic anemia and their relation to hemoglobin and catecholamine concentrations in fetal blood.

OBJECTIVES: Immune hemolytic anemia in the fetus may cause cardiac decompensation and intrauterine death. Postnatally, norepinephrine (noradrenaline) is released in chronic heart failure, and may lead to myocardial hypertrophy. The aim of this study was to determine fetal cardiac changes associated with immune hemolytic anemia by means of echocardiography, and to relate them to fetal hemoglobin and norepinephrine levels. DESIGN: Thirty anemic fetuses underwent a total of 76 umbilical venous transfusions. Before the procedure, fetal echocardiography was performed, and end-diastolic myocardial wall thicknesses and ventricular dimensions together with Doppler flow patterns at the atrioventricular and semilunar valves were measured. Fetal hemoglobin, epinephrine and norepinephrine concentrations were determined before the transfusion. Statistical analysis of this prospective study comprised descriptive statistics including linear regression and correlation analyses. Two samples of measurements were compared by the Mann-Whitney U test. RESULTS: The mean hemoglobin concentration before the first transfusion was 6.9 g% at a mean gestational age of 26.8 weeks. Norepinephrine values were elevated in comparison to a reference range, and were higher than epinephrine values. The most striking echocardiographic finding was myocardial hypertrophy of all ventricular walls. Mean blood flow velocities were increased; at the left ventricle, they were negatively related to the hemoglobin concentrations, and positively to the norepinephrine values. CONCLUSIONS: Fetal myocardial hypertrophy in anemia may be the result of an augmented cardiac workload, indicated by the increased left ventricular mean velocities. This reaction reflects the redistribution of blood flow that may depend on hemoglobin and norepinephrine concentrations.

Randomized observational studies on the economics of therapies--biometrical experience of two trials.

Economic studies in medicine are intended to investigate costs, associated with a particular problem dealing with the indication, diagnosis or therapy, for instance, whether the high costs involved in a highly intensive or innovative therapy could be balanced by the eventual savings made, due to the shorter periods of treatment. In such situations a randomized controlled trial is necessary to find out which therapy or which therapeutical strategy is least expensive in the long run. Economic studies do, however, present some specific problems. Making a list of all the cost-relevant treatment items can be very laborious, but the use of flat rates and lump sums alone cannot lead to a complete cost analysis. Often, costs between hospitals vary more than between treatment regimens. Early and sudden deaths incur low costs and may bias the results. Furthermore, costs are distributed with a long and heavy upper tail including extreme outliers. This does, in fact, complicate the estimation of the sample size. In this article, these problems are outlined and, with the help of the data obtained from two randomized economic trials in health care, solutions are proposed and discussed.

Reproducibility of measurements with a new slit lamp-mounted ocular blood flow tonograph.

PURPOSE: To assess the reliability of measurements of intraocular pressure (i.o.p.), pulse amplitude (PA), and pulsatile ocular blood flow (POBF) and the validity of measurements of IOP with a new ocular blood flow tonograph. METHODS: Intraocular pressure pulse was assessed with pneumatic tonometry. In this study, we used the OBF Labs ocular blood flow tonograph with two different pneumatic probes, a modified Langham probe and a newly developed probe. One ophthalmologist compared two machines, first with the modified Langham probe and secondly with the newly developed probe (40 volunteers). Additionally, two ophthalmologists performed measurements on different days and in different sequence (34 volunteers). Furthermore, results of IOP measurements performed with this tonograph were compared to those of Goldmann applanation tonometry (213 volunteers). RESULTS: Using the modified Langham probe, POBF and PA were associated with the machine used for the test. However, using the newly developed pobe, no relevant or statistically significant differences were found for any variables, and reliability coefficients were between 0.70 and 0.90. Linear regression analysis of the Goldmann applanation tonometer on the measurements of IOP with the tonograph showed a regression coefficient of 0.765. CONCLUSIONS: Results of measurements performed with this ocular blood flow tonograph and the newly developed probe are expected to be reliable and comparable.

Quantitative liver function tests as surrogate markers for end-points in controlled clinical trials: a retrospective feasibility study.

Quantitative liver function tests such as the determination of galactose elimination capacity (GEC) or the aminopyrine breath test (ABT) may have the potential to serve as refined entry criteria and surrogate markers for end-points in controlled clinical trials. The magnitude of a statistically detectable difference in test results and the period of observation required to document such a difference must be known to properly design such trials. Therefore, we explored retrospectively the time course of changes in GEC and ABT and their reproducibility from a cohort of patients with alcoholic cirrhosis followed for 12 to 42 months, with a median of 34 months. In 15 patients who stopped drinking, GEC improved significantly by 0.64 mg/min/kg within 1 year (mean; 95% confidence interval [CI]: 0.42; 0.86). In contrast, it deteriorated by 0.53 mg/min/kg within 1 year (95% CI: 0.32; 0.74) in another 17 patients who continued to drink (P < .01). The residual standard deviation of the changes in GEC with respect to the patients' initial values was 0.43 mg/min/kg (95% CI: 0.32; 0.52). In addition, ABT improved significantly by 0.14% dose x kg/mmol CO2 (95% CI: 0.09; 0.18) in the abstinent group, and deteriorated by 0.09% dose x kg/mmol CO2 (95% CI: 0.06; 0.13) in the nonabstinent group (P < .01). The residual standard deviation in the above sense for ABT was 0.08% dose x kg/mmol CO2 (95% CI: 0.06; 0.10). These data indicate that clinical trials with a sample size of n = 20 in each group must achieve absolute differences (ADs) in GEC of 0.6 mg/min/kg and of 0.7 mg/min/kg to reach statistical significance at the 5% and 1% level, respectively. In the present study, a period of 11 and 12 months was necessary to observe such differences. The corresponding results for the ABT are 0.11% dose x kg/mmol CO2 (9 months of follow-up; 5% level) and 0.13% dose x kg/mmol CO2 (11 months of observation; 1% level), respectively. Provided that patients with liver diseases treated with drugs are similar to the abstinent and nonabstinent patients with alcoholic liver disease investigated in this study, such numbers could serve for the planning of controlled clinical trials, in which the control group is likely to deteriorate and the treated group is expected to improve. Trials based on GEC or ABT would require only 37 or 30 patient years of observation compared with a median of 444 patient years (range, 50-2,100 patient years) reported for various published controlled clinical trials using survival analysis.