Biomedical subjects

Josef Bukac

Publications and source records attributed to Josef Bukac.

5 recordsLinked to original sources

PubMed2005

The sinus lift with phycogenic bone substitute. A histomorphometric study.

OBJECTIVES: The aim of this histomorphometric prospective study was to ascertain the efficacy of phycogenic bone substitute in an augmented sinus. The process of graft healing, bone remodeling, and biomaterial replacement was examined. MATERIAL AND METHODS: The phycogenic material (fluorohydroxyapatite) made from calcium-encrusted sea algae was used for the sinus lifts. Twenty-four procedures were carried out (one-stage and two-stage equally) and 45 titanium stepped-screw implants were placed. The patients were followed for 12-23 months. In intervals of 6, 9, 12, or 15 months after the sinus lift, 24 graft specimens were taken with a trephine bur. These specimens were examined histomorphometrically. RESULTS: The grafting material was gradually resorbed and replaced by newly formed bone. Between the sixth and 15th month after the sinus lift, the percentage of newly formed bone grew linearly (from 15.5+/-9.6% to 40.8+/-15.3%) and the percentage of bone substitute decreased linearly (from 34.5+/-8.6% to 13+/-9.6%). After 15 months, the density of trabeculae in grafted bone corresponded to cancellous bone of good quality; however, the bone substitute was not completely resorbed during this period. No significant difference between the quality of the newly formed bone in the cases of the one- and two-stage sinus lifts was found. CONCLUSION: Sinus lift carried out with phycogenic bone substitute was shown to be an effective method with limited invasiveness and a high survival rate of implants (97.8%).

Adolescent↗

PubMed2004

Costal cartilages--a clue for determination of sex.

Mineralization and ossification in the human costal cartilages were studied radiologically. The aim of our study was to evaluate differences between males and females with respect to patterns of costal cartilage calcification and also with respect to ageing. Material for this study consists of 1044 chest and abdominal radiograms of the Czech population from the Department of Radiology (537 males and 507 females). Further radiograms of 18 chest plates were obtained at routine necropsy of cadavers. The radiograms were examined for pattern of ossification of the costal cartilage. The first rib cartilages were not considered because there are no sex differences. The lower ribs exhibit sexual dimorphism. Mineralization and ossification changes appear at the end of puberty and their occurrence increases with age. The sexual difference in pattern of human costal cartilages is statistically significant and thus highly predictive of sex determination.

Adolescent↗

PubMed2004

[Our statistical programs in Excel].

We prefer to use a spreadsheet program when teaching statistics. We have written several programs to cover the methods students use. The input data are typed in the spreadsheet MS Excel, we mark the data, and the program creates an output table. The outputs are both in Czech and English, they contain the basic results useful for students, various alternatives, test criteria, acceptance regions, and p-values. Since the programs are user-friendly, they make it easier on students.

Software↗

PubMed2002

Troponins in experimental studies.

The aim of our study was to compare the diagnostic performance of cardiac troponin T (cTnT) and cardiac troponin I (cTnI) in three groups of rabbits: 1) control (saline 1 ml/kg i.v.); 2) daunorubicin (3 mg/kg i.v.); 3) daunorubicin (3 mg/kg i.v.) + dexrazoxane (60 mg/kg i.p.). The drugs were given once a week, 10 administrations. The concentration of cTnT was measured using Elecsys Troponin T STAT Immunoassay (Roche). The concentration of cTnI was measured using AxSYM Troponin I (Abbott). The linear regression model was applied to see if there is a dependence between cTnT and cTnI. The coefficient of determination (R2 = 0.79) was acceptable only in the control group. In the remaining cases (i.e. in the daunorubicin group and in the daunorubicin + dexrazoxane treated group) R2 was too small (0.53, and 0.06). We may conclude that in rabbits after repeated administration of cardiotoxic or cardioprotective drugs meaningful dependence between cTnT and cTnI was not found. The choice of the most suitable cardiomarker in laboratory animals deserves further studies.

Animals↗

PubMedDate not supplied

Development of gastric emptying in premature infants. Use of the (13)C-octanoic acid breath test.

OBJECTIVE: The non-invasive (13)C-octanoic acid breath test ((13)C-OABT) has recently been used to monitor gastric emptying. We evaluated (13)C-OABT as a method for assessing gastric emptying in relation to the amount of milk ingested in preterm neonates during their first days of life. METHODS: The (13)C-OABT was performed in 16 stable preterm neonates born between weeks 31 and 37 of gestation (mean +/- standard deviation: 34.0 +/- 1.5 wk). Birth weight was 1400 to 2680 g (2076 +/- 350 g); four newborns were small for gestational age. The newborns underwent (13)C-OABT three times according to the amount of (13)C-primed breast milk being fed to them (<7 mL/kg, 7-13 mL/kg, and 10-19 mL/kg per dose). (13)C-primed breast milk (the test meal) was prepared by adding (13)C-octanoic acid to pasteurized breast milk to achieve a concentration of 1 microL of (13)C-octanoic acid/mL of milk. Exhaled air samples were taken through an original nasal mask. Amounts of (13)C and (12)C in the exhaled air samples were measured by mass spectrometry. Results were expressed as delta over baseline and related to the international standard of Pee Dee Belemnite Limestone. To assess the half-life of elimination (t(1/2)E), we modeled the process of elimination with the incomplete gamma-function, which has a convenient form for the empiric plotting of breath test data. We estimated the parameters of the function, f(x) = A x(b) e(-cx), by using the moment method. The curves were determined by the t(1/2)E of (13)CO(2) and characterized by the shape of the elimination curve. The half-time of gastric emptying (t(1/2)GE) was calculated as t(1/2)E reduced by the mean metabolic half-time of octanoic acid. RESULTS: Forty-eight (13)C-OABT results from 16 premature newborns were analyzed. The mean and median of t(1/2)GE calculated from all three tests were 50.3 (+/-29.9) and 43.7 min, respectively. The t(1/2)GE did not change significantly (P = 0.6811) with the administered dose of (13)C-primed breast milk in the stomach. The coefficient of variation among the studied infants was 4.0% to 33.6% (mean, 11.5%). In 12 infants, the characteristic type of elimination curve was the same for all three tests. CONCLUSIONS: In the first hours of gastric feeding, neither the age of the neonate nor the amount of administered (13)C-primed breast milk had any effect on t(1/2)GE. The gastric emptying rate and the evacuation curve shape for individual neonates were similar and independent of milk amount.

Breath Tests↗