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Biomedical subjects

A Knezević

Publications and source records attributed to A Knezević.

At least 19 recordsLinked to original sources
PubMed2005

Reduced quantity and hydrogen-peroxide production of vaginal lactobacilli in HIV positive women.

It has been suggested that vaginal lactobacilli may influence heterosexual transmission of HIV infection. The aim of this study was to compare the vaginal flora on Gram's stained and isolation rate, quantity and H2O2 production of lactobacilli between HIV positive and HIV negative women. Although, the prevalence of abnormal vaginal flora was increased in HIV infected women, there was no significant difference in isolation rate of vaginal lactobacilli between the two groups (71.87 vs. 83.33%; P>0.05). However, the results of this study showed significantly reduced quantity of lactobacilli in HIV infected women (P<0.01). In particular, the prevalence of H2O2-producing lactobacilli was lower in HIV positive as compared to HIV negative women (80 vs. 56.52%), with borderline significance (P=0.057). Taken together, our findings showed altered vaginal microflora with reduced quantity and hydrogen-peroxide production of vaginal lactobacilli in HIV positive women, but further studies are needed to assess its actual significance and potential benefit from the use of probiotic therapy.

Adult↗
PubMed2005

Influence of light intensity from different curing units upon composite temperature rise.

The unavoidable consequence of composite resin photopolymerization is temperature rise in tooth tissue. The temperature rise depends not only on the illumination time, but also on light intensity, distance of light guide tip from composite resin surface, composition and shade of composite resin and composite thickness. The most commonly used units for polymerization today are halogen curing units, which emit a large spectrum of wavelengths. A proportion of the spectrum has no influence on degree of conversion and therefore causes unnecessary temperature rise. Units based on light source - blue light emitting diodes (LED), as an alternative for halogen curing units, have been introduced in clinical practice. The aim of this study was to show the influence of the light intensity of curing units Elipar Trilight, Astralis 7 and Lux-o-Max unit on temperature rise in composite resin sample of Tetric Ceram. The temperature was measurement with Metex M-3850 D multimeter with the tip of temperature probe put into unpolymerized composite resin sample 1 mm depth. The highest temperature rise was recorded with standard curing mode for Elipar Trilight halogen curing unit (13.3 +/- 1.21 degrees C after 40 s illumination), while the lowest temperature rise was recorded for the Lux-o-Max unit based on LED technology (5.2 +/- 1.92 degrees C after 40 s illumination).

Composite Resins↗
PubMed2005

Transaortic double valve replacement in difficult mitral valve exposure.

Adequate open exposure of the mitral valve is necessary to accomplish reconstruction or replacement of the diseased mitral valve apparatus. The technique employed by most cardiac surgeons for mitral valve access involves median sternotomy and vertical left atriotomy posterior to the interatrial sulcus. However, certain conditions can somethimes make this approach very difficult. Different approaches are discussed with particular emphasis on our case in which the transaortic double valve replacement have been performed.

Aortic Valve↗
PubMed2004

Changes in the Hurst exponent of heartbeat intervals during physical activity.

The fractal scaling properties of the heartbeat time series are studied in different controlled ergometric regimes using both the improved Hurst rescaled range (R/S) analysis and the detrended fluctuation analysis (DFA). The long-time "memory effect" quantified by the value of the Hurst exponent H>0.5 is found to increase during progressive physical activity in healthy subjects, in contrast to those having stable angina pectoris, where it decreases. The results are also supported by the detrended fluctuation analysis. We argue that this finding may be used as a useful new diagnostic parameter for short heartbeat time series.

Adaptation, Physiological↗
PubMed2004

Foley catheter and deep hypothermic circulatory arrest to control bleeding in redo cardiac surgery.

Two cases with catastrophic hemorrhage in redo cardiac surgery are described. In the first one tearing of right ventricle with uncontrolled bleeding occurred during sternal reentry. In the second one, tearing of the right atria occurred while the patient was on cardiopulmonary bypass. In both cases we were able to control bleeding using Foley catheter, which enabled us to proceed to deep hypothermic circulatory arrest to repair heart chambers (due to dense adhesions it was impossible to manage it in any other way). We have found this combined technique to be extremely useful tool to control catastrophic hemorrhage during redo cardiac surgery.

Blood Loss, Surgical↗
PubMed2003

[Surgical revascularization of the myocardium].

It has been 45 years ago when Longmire (1958.) used internal thoracic artery (ITA) for the first time in coronary artery bypass surgery (CABG). In this review, we are presenting novel surgical approaches in CABG surgery. We have also been summarized the best of knowledge, up to date, regarding histology, pharmacology and pathophysiology of conduits (VSM, ITA and alternative venous and arterial grafts) which have been used in CABG surgery, as well as factors influence on its short and long-term patency.

Coronary Artery Bypass↗
PubMed2003

Postcardiotomy assisted circulation with roller pump--early and late results.

The incidence of postcardiotomy myocardial failure (PMF) requiring mechanical circulatory support beyond IABP is reported to be 0.2% to 1.2%. From Dec. 1989 through Dec. 1995, 18 patients (0.3% of the total pump cases) were supported with roller pump type of LVAD. Assisted flow ranged from 3.5 up to 5 L/min with average support time of 35.5 hours. Six (33.3%) patients died while on LVAD. The causes of additional seven deaths (pts weaned of LVAD) were: myocardial failure (4), stroke (2) and intractable bleeding during removal of the LVAD (1). Overall, five patients (27.8%) were successfully discharged from the hospital. Two out of five long-term survivors died later, 6 months and 4 years postoperatively, both of cardiac causes. The actuarial survival rate of long-term survivors was 60% at 7 years, all of them being in NYHA functional class II. These results have proved efficiency of roller pump driven LVAD for short-term circulatory support in pts with PMF. Results are comparable to so far published data on postcardiotomy support with the same, as well as other types of more versatile and costly devices.

Aged↗
PubMed2002

Composite conversion and temperature rise using a conventional, plasma arc, and an experimental blue LED curing unit.

The objective of this study was to evaluate the degree of conversion and temperature rise in three different composite materials when illuminated by an experimental light source [blue superbright light emitting diodes (LEDs)] and compared with plasma light and traditional photopolymerization unit. The degree of conversion and temperature rise were measured using Fourier transform infrared (FTIR) spectroscopy and digital multimeter, respectively. The results revealed significantly higher degree of conversion values in case of conventional curing than with other two light sources whereas temperature rise was significantly lower when blue LEDs and plasma light were used. There were great differences in light intensities between blue LEDs of only 9 mW cm-2 compared with plasma light of 1370 mW cm-2 and Elipar II of 560 mW cm-2. Better match of LED spectral distribution peak to camphorquinone absorption distribution peak probably explains much lower intensities used for similar photopolymerization effect like in the case of rapid plasma lamp curing.

Absorption↗
PubMed2002

Photopolymerization of composite resins with plasma light.

Everyday improvements in components and characteristics of composite materials have induced faster development of curing units. Besides standard halogen curing units and soft-start photopolymerization light sources, some experiments with argon and pulsed laser light and low intensity blue superbright light emitting diodes have been made. On the other hand, rapid polymerization with strong plasma light is also clinically applicable. The aim of this study was to measure the degree of conversion and temperature rise for three restorative composite materials: Tetric Ceram (Vivadent, Schaan, Liechtenstein), Pertac II (ESPE, Seefeld, Germany) and Z100 (3M Dental Products, St Paul, MN, USA) during polymerization with plasma light Apollo 95E (DMDS, Dental/Medical Diagnostic Systems, Fleury d'Aude, France) and compare it with the results of polymerization with a halogen curing unit, Elipar Trilight (ESPE, Seefeld, Germany). The results revealed the degree of conversion values in the case of polymerization with plasma light to be almost equal to those obtained by curing with the halogen curing unit, whereas the temperature rise was almost negligible.

Analysis of Variance↗
PubMed2002

Influence of diet on dental caries in diabetics.

Two groups of population consisting of 84 patients suffering from diabetes (60 type I, 24 type II) and 69 nondiabetics of the same age have been examined on: oral hygiene index (OHI), frequency of daily tooth brushing, dietary habits and incidence of dental caries by registration of the decayed, missed and filled dental surfaces (DMFS-index). OHI in type I and type II diabetes was found to bee slightly worse than in nondiabetics, but not significantly (p > 0.05). In the number of daily tooth brushing there is not significant difference between diabetics and nondiabetics. All diabetics have considerably lower daily intake of total as well as simple carbohydrates than nondiabetics. The diabetics have a significantly higher daily intake of dietary fibers, calcium and phosphorus as well as the number of meals with simple carbohydrates and also DMFS-index than the nondiabetics. A significantly higher incidence (p < 0.01) of caries location was found on the buccal and labial cervical areas among patients suffering from diabetes. Explanation for this could be more frequent daily intake of low molecular carbohydrates with an improper calcium phosphorus ratio.

Adult↗
PubMed2002

Double tooth.

The form of primary and permanent teeth can differ morphologically from that which is considered normal, completely or in some parts. The changes in tooth form can be hereditary or caused by some disease or trauma. Fusion is a union of one or more teeth during development. Gemination means that two separate morphological units were created by division of the tooth germ. The intention of this study was to state the prevalence of double teeth (fusion and gemination) among the persons tested, as to gender, distribution in the maxilla or mandible, and whether the anomaly occurred bilaterally or unilaterally. The results of this investigation have shown that in a total of examined 3,517 plaster models, a prevalence of double teeth was 0.2%. 57.2% of them were fusioned and 42.9% geminated.

Female↗
PubMed2001

Degree of conversion and temperature rise during polymerization of composite resin samples with blue diodes.

To ensure an adequate clinical composite filling light source for photopolymerization is of great importance. In everyday clinical conditions commonly used unit for polymerization of composite material is halogen curing unit. The development of new blue superbright light emitting diodes (LED) of 470 nm wavelengths comes as an alternative to standard halogen curing unit of 450-470 nm wavelengths. The purpose of this study was to compare the degree of conversion (DC) and temperature rise of four hybrid composite materials: Tetric Ceram, Pertac II, Valux Plus and Degufill Mineral during 40 s illumination with standard halogen curing unit Heliolux GTE of 600 mW cm(-2) intensity, Elipar Highlight soft-start curing unit of 100 mW cm(-2) (10 s) and 700 mW cm(-2) (30 s) intensity and 16 blue superbright LED of minimal intensity of 12 mW cm(-2) on the surface and 1 mm depth. The results revealed only a little bit higher DC values in case of polymerization with even 66 times stronger halogen curing units which showed twice higher temperature than blue diodes. Temperature and DC obtained are higher on the surface than on 1 mm depth regardless on the light source used.

Analysis of Variance↗
PubMed2001

The efficiency of dentine adhesives in treating non-caries cervical lesions.

The aim of this study was to prove the hypothesis that dentine adhesives can be used as therapeutic material in treating dentine hypersensitivity, regardless of aetiology. The research was conducted on 492 students of Zagreb University School of Dental Medicine (154 male, 338 female), 20-25-years-old. The defects of the tooth neck were found in 38 patients, on 133 teeth (38 of male patients, 95 of female) and dentine hypersensitivity was recorded according to the subjective sensations of patients. Therapeutic characteristics of three adhesive materials were examined simultaneously: All Bond 2, fourth generation adhesive, Syntac Single Component and One Step, fifth generation adhesives. Teeth treated with dentine lacquer Cervitec were used as a control group. Tooth necks were treated with selected materials according to instructions of a manufacturer. A completed statistical survey of the results has clearly shown that dentine adhesives can be used in symptomatic therapy of dentine hypersensitivity of the non-caries cervical lesions (NCCL). The survey has also shown that dentine adhesives of the fifth generation (Syntac Single Component and One Step) have much higher efficiency rate than dentine adhesives of the fourth generation (All Bond 2) and dentine lacquer (Cervitec). According to data complied through this study the conclusion can be brought forward that dentine adhesives are not a final solution to the problem of dentine hypersensitivity, because their efficiency decreases with time.

Adult↗
PubMed2001

[Assisted circulation. I. Systems with short-term mechanical circulatory support].

The concept of artificial circulatory support has been established almost 200 years ago. It has only been within the last four decades that physicians and engineers have developed mechanical assist devices that can temporarily support the circulation until the native heart recovers from a reversible injury. If the heart does not recover sufficient function to maintain adequate hemodynamics, long-term circulatory support or permanent replace (biologically--heart transplant or permanent mechanical circulatory support) is needed. In this paper we describe the devices (intraaortic balloon pump, roller, centrifugal and axial pumps), that are in current clinical use for temporary (short-term) mechanical circulatory support.

Assisted Circulation↗
PubMed2001

[Assisted circulation II--systems for intermediate and long-term mechanical circulatory support].

The concept of artificial circulatory support has been established almost 200 years ago. It has only been within the last four decades that physicians and engineers have developed mechanical assist devices that can temporarily support the circulation until the native heart recovers from a reversible injury. In patients who do not regain native heart function, long-term circulatory support or permanent replace (biologically--heart transplant or permanent mechanical circulatory support) is indicated. In this paper we describe the devices (ABIOMED BSV 5000, Thoratec, HeartMate, Novacor and CardioWest TAH), that are in current clinical use for intermediate and long-term mechanical circulatory support.

Assisted Circulation↗
PubMed1996

[Ethics in psychopharmaceutical research].

This paper deals with deontological considerations, especially with ethical aspects of examining drug effects in psychiatric institutions. These observations are based on the author's ten-year research experience.

Ethics, Medical↗
PubMed1995

[Difficulties in the treatment of depressive disorders].

All troubles and difficulties of depressive patients are, from first atypical and mild symptoms, presented to full development of a depressive disease. Particularly, there are difficulties to make a difference between neurotic and functional depression, owing to atypical and masked forms of this disorder, as well as lack of real criteria for a selective clinical use of antidepressive agents.

Depressive Disorder↗