Biomedical subjects

B Fink

Publications and source records attributed to B Fink.

At least 37 records · Page 2Linked to original sources

PubMed1995

[Factors affecting bone regeneration in Ilizarov callus distraction].

We evaluated the X-rays of 36 patients who underwent 50 callus distractions. With the aid of a computerized digitalisation system for analogue films, the relative X-ray density of the distraction area was calculated for each X-ray. These relative X-ray densities were figured graphically for the duration of treatment for each patient. In the consolidation phase, the graph of each patient had a logarithmic relationship. The gradients of the logarithmic density curves were considered an indicator of the quantity of new bone formation. These gradients were correlated to the following clinical parameters: age of the patient, beginning of distraction after corticotomy, average speed of distraction, average weight bearing during the distraction and consolidation phase, location of corticotomy (distal femur versus proximal tibia) and diclofenac medication. Except for the location of the corticotomy and diclofenac, all parameters had an influence on osteoneogenesis by callus distraction. The parameters affecting new bone formation the most were the age of the patient and weight bearing. Patients aged under 18 years (p = 0.005), beginning of distraction later than 8 days (p = 0.109), an average distraction speed below 1 mm/day (p = 0.079), and average weight bearing of more than 30 kg (p = 0.068 for the distraction phase and p = 0.089 for the consolidation phase) showed a quantitatively higher rate of new bone formation by callus distraction than the patients in the other groups. Patients with a shorter leg due to poliomyelitis and one patient with an amniotic leg tie showed a slower increase in X-ray density graphs than the other patients.

Absorptiometry, Photon↗

PubMed1995

Effect of ITF 296 on total effective vascular compliance in the anesthetized dog under autonomic blockade.

The effects of ITF 296 on venous tone, estimated as changes in total effective vascular compliance (TEVC), were investigated in the anesthetized, spontaneously breathing dog under autonomic blockade. TEVC was calculated from the correlation between the observed changes in central venous pressure (CVP) and the experimentally induced changes in blood volume during an 11-min cycle of whole blood infusion (2 ml/kg/min), withdrawal, and reinfusion. Stepwise increasing doses (short steady-state infusions) of ITF 296 (3, 10, and 30 micrograms/kg/min) resulted in a dose-dependent increase in TEVC (+27, +54, and +67%), whereas mean blood pressure (MBP) was reduced (-12, -23, and -33%, respectively). SIN-1 (10 micrograms/kg/min), administered at the end of the experiment as the reference NO-releasing compound, induced a rather complete venodilation (TEVC +182%) and a marked reduction in MBP (-47%). When nitroglycerin (NTG) was used as the reference compound at 1.5 micrograms/kg/min, a 67% increase in TEVC was observed. These results suggest that ITF 296 exerts a venodilator action but that this effect, and therefore the reduction in venous return, is less than that in response to nitrovasodilators such as SIN-1 or NTG. Furthermore, the vasodilator spectrum of ITF 296 compared to other nitrovasodilators is shifted somewhat more toward the arteriolar bed, with less pronounced venodilator effects, as indicated by the fall in MBP.

Anesthesia↗

PubMed1995

Effects of ITF 296 on epicardial coronary artery diameter during acute and long-term treatment in the conscious dog.

The action of the newly developed organic nitrate ITF 296 on large coronary arteries was investigated during acute and long-term treatment in the conscious dog, chronically instrumented for recording of large coronary artery diameter (CD), mean arterial blood pressure (MBP), and heart rate (HR). Short-term steady-state infusion of ITF 296 at doses of 0.1-30 micrograms/kg/min induced a dose-dependent increase in CD. Maximal coronary artery dilation (+11%) was reached at 10 micrograms/kg/min and no further increase was observed at 30 micrograms/kg/min. At the same doses no significant variations of MBP or HR were observed. Long-term administration (5-day infusion) of ITF 296 at 20 micrograms/kg/min resulted in a 10% increase in CD, and the effect was well maintained over the entire infusion period. MBP did not change significantly, whereas HR rose by 21% by the second day of infusion and remained elevated until the end of the treatment. These results confirm that ITF 296 is an effective dilator of large coronary arteries at doses devoid of peripheral hemodynamic effects. Moreover, the vasodilating effect on coronary arteries is well maintained during long-term administration, suggesting a reduced tolerance development.

Animals↗

PubMed1994

Reduced nitric oxide formation causes coronary vasoconstriction and impaired dilator responses to endogenous agonists and hypoxia in dogs.

We investigated the relative contribution of basal and agonist stimulated EDRF/NO release to the adjustment of coronary tone and myocardial perfusion in conscious dogs by inhibiting coronary endothelial NO formation with NG-nitro-L-arginine methyl ester (L-NAME). Chronically instrumented conscious dogs (n = 9) were prepared for measurement of mean arterial blood pressure (MAP), heart rate (HR), coronary blood flow (CF) and diameter of the left circumflex (CDLC) and left anterior descending (CDLAD) coronary artery, respectively. Intracoronary infusions of L-NAME (30.3 mM; 0.25 ml x min-1) caused significant increases in MAP and decreases in HR. CDLC decreased by 3.8% from 3.01 +/- 0.04 to 2.90 +/- 0.04 mm and CF decreases by 30% from 12.9 +/- 0.2 to 9.1 +/- 0.2 (aU). Peak reactive hyperemia (CFmax) evoked by 20-s-lasting occlusions of the left circumflex coronary artery decreased from 29.9 +/- 0.8 to 25.8 +/- 1.0 aU and maximal flow-dependent coronary dilation were reduced from 2.04 +/- 0.08 to 0.91 +/- 0.12% after inhibition of NO-synthesis. Intracoronary infusions of acetylcholine (ACh), adenosine (Ado), bradykinin (Bk), and papaverine (Pap) caused dose-dependent increases in CDLC and CF. Infusion of L-NAME nearly abolished the dilator effect of Ado on CDLC and reduced those to ACh, Bk and Pap. Increases in CF to ACh, Ado and Bk but not to Pap were reduced by L-NAME. Subsequent intracoronary infusions of L-arginine (303 mM; 0.25 ml x min-1) reduced L-NAME-induced CF-changes partly, but did not reverse coronary constriction. These results suggest that inhibition of the continuous release of nitric oxide markedly reduces myocardial perfusion in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Image analysis and synthesis of multimodal images in medicine.

Radiologic and clinical practice can be enhanced by improved access to multimodal image information. Analysis, visualization, method characteristic image processing and image synthesis is needed not only for the interpretation of the images but also for performing effective consultations with clinical colleagues and computer supported therapy planning and control strategies. A method is presented which enables the fast display, three-dimensional visualization and the modality oriented analysis of multimodal image information. Based on a unique image format, modality specific procedures and two- or three-dimensional processing tools of image analysis produce the input data for therapy planning programs. The easy use of this multimedia visualization tool enables radiologists and clinicians to deal with their image data. The description of methods and procedures, as well as typical examples of radiologic practice will demonstrate the efficiency of the presented system.

Algorithms↗

PubMed1994

Long term increases in coronary arterial conductance during five day infusion of low dose nicorandil.

OBJECTIVE: The aim was to test the effects of nicorandil on coronary arterial conductance and on a possible development of tolerance or cross tolerance with glyceryl trinitrate during a 5 d continuous intravenous infusion of this hybrid molecule (consisting of a combination of potassium channel activation and simultaneous nitro-ester induced soluble guanylyl-cyclase activation). METHODS: Continuous intravenous infusions of nicorandil at 2.5 micrograms.kg-1.min-1 and 10 micrograms.kg-1.min-1 into conscious chronically instrumented dogs were carried out for 5 d using a special portable infusion system. Employing additional short term infusions, dose-response curves were obtained by giving nicorandil or glyceryl trinitrate at increasing dosages both in the preinfusion control state and 4 h after terminating the nicorandil infusion. RESULTS: The 5 d infusion of 2.5 or 10.0 micrograms.kg-1.min-1 nicorandil resulted in a significant increase in large coronary artery diameter by 4.21 (SEM 0.14)% or 9.20(0.28)%, respectively. At the lower dose no significant tolerance or cross tolerance with glyceryl trinitrate was observed. However, at the higher dose there was a shift of the dose-response curve of both nicorandil and glyceryl trinitrate to the right, indicating some tolerance. The smaller dose did not induce hypotension or reflex increase in heart rate, whereas the larger resulted in a 42(2.5)% increase in heart rate. CONCLUSIONS: A dose regimen of 2.5 micrograms.kg-1.min-1 continuously administered for 5 d is capable of inducing a significant increase in coronary arterial conductance which was well maintained over the whole infusion period. Thus nicorandil can exert a selective large coronary artery dilatation and may bring about a well maintained increase in epicardial coronary conductance, especially when applied as a low dose slow release preparation which circumvents hypotension and increase in heart rate.

Animals↗

PubMed1994

Long-term results of elbow arthroscopy in 67 patients.

Based on the results of a retrospective study of 67 patients with diagnostic and surgical arthroscopy of the elbow from 1977 until 1991, we present our technique, results, complications, and indications for elbow arthroscopy. The average age of the patients was 26 years (range: 11-59). At the time of follow-up the patients were examined clinically as well as radiologically. The results were scored according to Figgie's score, which is based on the criteria of pain, function, power and range of motion. The overall score significantly increased from 61.6 preoperatively to 85.3 postoperatively. The age of the patient did not influence the results. However, patients who were laborers had a poorer outcome than the others. Patients with preoperative pain for 2 months to two 2 years had better results than patients with a preoperative course of more than 2 years.

Adolescent↗

PubMed1993

Treating gunshot femoral shaft fractures with immediate reamed intramedullary nailing.

Reamed intramedullary nailing was used within 36 hours of patient admission to treat 32 consecutive femoral shaft fractures caused by low-velocity gunshot wounds. The femoral shaft fracture was classified according to the AO system, and comminution was graded according to the classification of Winquest and Hansen. Patients were followed for an average of 14.7 months (range, 6 to 36 months), and the average time to union was 18.6 weeks. The average hospital stay was 7 days, which is approximately one half the average stay reported in the literature for treating this kind of injury with delayed nailing. The shorter hospital stay represents potential savings of up to $9,000 per patient. Immediate intramedullary rodding is a safe, effective, and economic option for the treatment of a femoral shaft fracture caused by a low-velocity gunshot wound. However, a lack of compliance with instructions concerning weight-bearing in this patient population needs to be taken into account when planning postoperative care.

Adolescent↗

PubMed1992

Frequency of curettage in middle-aged women treated with sequential preparations versus untreated women.

Over a 2-month period a register was kept of all dilatation and curettage procedures performed in Frederiksborg County, Denmark, involving women aged 40-59 years. The total recorded was 284. In the same period, questionnaires were sent out to 1200 women in the county who fell within the same, randomly selected age group, to establish the number of women treated with sequential oestrogen/progestogen and those who had been hysterectomized. Based on the results and the total female population in the county, it was calculated that the frequency of the procedure in sequentially-treated women as compared with untreated women was 3.1 times higher in the 55-59 age group. In the 40-54 age group no difference in the incidence of curettage in the sequentially-treated women could be demonstrated.

Adult↗

PubMed1992

Pathophysiology of unilateral high-grade carotid artery stenosis: evaluation of intracranial haemodynamics by analysis of velocity waveforms from the middle cerebral artery.

1. Transcranial flow velocity waves were measured via Doppler sonography of the middle cerebral artery during hypo-, hyper- and normo-capnia. Applying the principle of vascular impedance, flow velocity waves were analysed in 30 young subjects, 37 elderly subjects and 18 patients with high-grade unilateral internal carotid artery disease. 2. There was evidence that the relative peak-to-peak velocity in the middle cerebral artery could serve as an index of peripheral wave reflection and cerebral resistance (CRi). The response of CRi to changes in arterial CO2 concentration (CRi reactivity) showed a clear age-dependency. However, the absolute side-to-side asymmetry of CRi reactivity (delta R) did not vary with age and could be used to define a normal range (0-4%CRi/vol.%CO2). 3. Selective angiography demonstrated no cerebral cross-flow through the anterior part of the circle of Willis in nine patients with carotid artery stenosis whose absolute delta R was above the normal range and whose CRi reactivity of the affected hemisphere was lower than that of the healthy opposite hemisphere. Conversely, another group of nine patients, whose ipsilateral CRi reactivity was higher than the contralateral CRi reactivity, demonstrated cross-flow through the anterior part of the circle of Willis. 4. delta R may be used to identify patients who have high-grade internal carotid artery stenosis and present with low cerebral vascular resistance owing to poor intracerebral collaterals.

Adult↗

PubMed1992

[Ilisarov ring fixation and its technical application].

The Ilisarov ring fixator is an extremely versatile external fixation device. There is a wide range of indications for its use, e.g. fractures, pseudarthroses and non-unions, large defects, deformities and limb shortening. The device consists of rings or half-rings, which are connected to each other by threaded rods or plates and to the bone by wires under tension. This design allows neutral fixation, compression or distraction of the bone fragments. Because of its low axial stiffness at low loads and increased stiffness at higher loads, this fixator promotes osteogenesis and reduces strain on the tissues in functional treatment. Surgical intervention for its application is minimally invasive. This is a useful addition to the orthopaedic surgeon's armamentarium, providing proper attention is paid to preoperative planning, the principle rules of frame design and wire insertion technique, and postoperative management.

Biomechanical Phenomena↗

PubMed1992

[Fracture treatment in the area of the tibia].

From May 1990 to March 1992 17 open and 6 closed fractures of tibia and fibula with second- to third-degree soft tissue injuries were treated by external fixation using the Ilisarov technique. In 14 patients this external fixation was used as the primary treatment. In nine cases it was used secondarily, mainly in patients transferred after stabilization with other internal or external devices. The mean duration of fixation for diaphyseal tibial fractures was 127 days and for metaphyseal fractures, 107 days. After removal of the fixation device, a brace was temporarily fitted for full weight-bearing. Disadvantages observed include less comfort for the patient and longer operation time compared to other external fixation systems. On the other hand, this method allows full weight-bearing soon after the operation and involves minimal damage of soft tissue. Furthermore, injured soft tissue was well protected during healing.

Adolescent↗

PubMed1992

[Treatment of post-traumatic limb shortening].

The physiological phenomenon of changes in callus formation during distraction was first described by Codivilla at the beginning of this century. Having investigated and proved the influence of tension stress on callus formation, Ilizarov used this as a method to treat limb shortening and deformities. Because of his remarkable results we introduced this method in our hospital in 1990, using the original Ilizarov ring fixator. From November 1990 to December 1991, we used this technique in 10 cases of combined post-traumatic bone shortening with deformity (the tibia was affected in six patients, the femur in three and the forearm in one). The mean shortening was 3.1 cm, the mean varus or valgus deformity 9.5 degrees, the mean anteflexion or recurvation 8.3 degrees, and the mean rotation deformity 8.5 degrees. Distraction/correction lasted between 8 and 55 days (mean: 37 days). Fixation was necessary for between 60 and 339 days. If corticotomy was performed in the diaphyseal bone, fixation lasted almost twice as long (11.33 days/mm lengthening) as in the metaphyseal area (6.55 days/mm lengthening). There were 14 complications, most of which were considered minor. The latter included pin infections (4), wire breaking (1) and restricted range of motion of the knee or ankle (5). Among the major complications were two nerve irritations, which recovered spontaneously, and two pin-induced local bone infections, which required surgical intervention. Achievement of the goals of treatment-complete correction of shortening and deformity-was not affected by these complications.

Adult↗

PubMed1992

[Treatment of chronic osteitis of the femur].

Since May 1990, we have treated seven patients with chronic osteomyelitis of the femur. The Ilisarov apparatus was used in three of these cases for fixation and in four cases for segment transport. The treatment of four patients is now complete. We have not found any problems in bone regeneration. The use of pins in the proximal and middle thirds of the femur has proved problematic due to the soft tissue damage. Instead of this, we recommend using Schanz screws, which can be fixed to the arch with the AO lock. Moreover, it is easier to shorten the 180 degrees arch to 90 degrees or 120 degrees using the Schanz screws. To prevent problems, it is better to assemble the apparatus before use and to take into consideration the anatomical and functional situation.

Adult↗

PubMed1992

[Treatment of chronic osteitis of the tibia].

Since the beginning of May 1990, we have been using the original Ilisarov apparatus in our treatment of osteomyelitis. It has been used both statically and dynamically after corticotomy for segment transport and lengthening. So far we have treated 24 patients, of whom 13 had defect osteomyelitis, 9 had unstable infections and 2 had stable osteomyelitis with deformities. On average the bone defects measured 7.6 cm, and nine patients had soft tissue defects larger than 6 cm2. The Ilisarov apparatus performed a holding function in seven cases after defect grafting using autogeneic spongiosa. It was used in four cases for gradual compression, in seven cases for segment or fragment transport, in three cases for secondary lengthening and in three cases for correction. In all cases the infections were eliminated and stability was obtained. The duration of segment transport corresponded to the defect size, with a daily lengthening of approximately 1 mm. The fixation times ranged from 112 to 483 days (mean: 240 days). Apart from one special situation, no bone regeneration problems were observed. Some of the complications we encountered must be regarded as beginners' mistakes. We observed problems with segment transport (early corticotomy healing, deformity, non-union at the docking site) and problems with equipment, which has now been improved. For closure of the soft tissue defects it was sufficient to use mesh grafting. Its versatility and advantages as a stabilizing apparatus have made the Ilisarov fixator the instrument of our choice, especially in the treatment of circular infected defects larger than 3 cm.

Adult↗

PubMed1991

Cyclic stress analysis of flexor tendon repair.

A method of evaluating flexor tendon repair techniques with the use of cyclic testing is presented. This type of evaluation complements the presently used load-to-failure tests by providing more detailed information about gap formation at the repair site. During load-to-failure testing in this study, core sutures alone demonstrated initial gap formation at 0.85 kg tensile force or more; yet on cyclic testing all techniques demonstrated gap formation of 1.9 mm or greater at 0.5 kg tensile force. Thus cyclic testing demonstrated gap formation not readily apparent on load-to-failure testing. An epitenon stitch placed circumferentially around the laceration site added strength in both load-to-failure and cyclic tests, and significantly reduced gap formation regardless of the core suture technique.

Hand↗

PubMed1990

A family history study of neuropsychiatric disorders in the adult siblings of autistic individuals.

The family history method was used to obtain developmental, social, and psychiatric histories on the 67 adult siblings of 37 autistic probands. Two of 67 siblings (3.0%) were autistic, three siblings (4.4%) had severe social dysfunction and isolation, 10 (15%) had cognitive disorders, and 10 (15%) had received treatment for affective disorder. This study is the first to investigate the frequency of disorders in the adult siblings of autistic probands. These results suggest aggregation of a variety of neuropsychiatric disorders in the siblings of autistic individuals.

Adolescent↗

PubMed1990

Screening workers exposed to 4,4'-methylenebis(2-chloroaniline) for bladder cancer by cystoscopy.

A bladder cancer incidence study was conducted among 540 workers exposed to the potential bladder carcinogen 4,4'-methylenebis(2-chloroaniline) from 1969 to 1979. Among the 385 workers who participated in a urine screening examination, none had suspicious or positive cytology. Twenty-one workers had at least one reading of atypia and 60 had either a positive dipstick for heme or greater than five red blood cells per low power field. The study protocol initially involved referral to private physicians for follow-up of any suspicious laboratory results. However, the diagnosis by cystoscopy of a bladder tumor in a nonsmoking man less than 30 years old with low-level hematuria prompted us to offer cystoscopy to all members of the cohort. A total of three tumors were identified in 200 persons who received cystoscopy. All were low-grade, papillary tumors and two occurred in men with completely normal urine screening results. These findings suggest that cystoscopy of asymptomatic persons should be considered in designing bladder cancer screening programs in high-risk cohorts.

Adult↗