Search PubMed⌕ Search

Biomedical subjects

J Dvorak

Publications and source records attributed to J Dvorak.

At least 145 records · Page 8Linked to original sources
PubMed1988

The outcome of surgery for lumbar disc herniation. II. A 4-17 years' follow-up with emphasis on psychosocial aspects.

We propose that the operated patients without complaints, patients with complaints and pensioned patients with complaints differ in their psychosocial situation. Thus, the first group show the best and the third the worst psychosocial condition. A sample of 135 patients after disc surgery was chosen at random from the patient population (n = 435) responding to a questionnaire. The patients were divided into three groups: no pain (n = 51), pain, no pension (n = 40), pain and a disability pension (n = 44). All have attended a psychosocial screening. They filled in the MMPI and were interviewed on some aspects of their social life, and reported on the coping modes they used in order to subdue their low-back complaints before or after the operation. Independent from the preoperative low-back pain condition and the immediate postoperative results, the operated patients showed, several years after the operation, traceable differences in several psychosocial factors according to the socially and personally defined illness career and its stages. The difference is particularly strong between the patients without complaints and the pensioned patients. The patients with complaints, mainly those receiving a pension, showed more psychopathological features as monitored on MMPI than the patients without complaints. They also reported substantially less satisfactory occupational, family and social life than the patients considered to be complaint-free. Finally, they also differed in their modes of coping with their back problems.

Adaptation, Psychological↗
PubMed1987

Functional anatomy of the alar ligaments.

Nineteen upper cervical spine specimens were dissected to examine the macroscopic and functional anatomy of alar ligaments. They are on both sides, symmetrically placed, approximately 10-13 mm long and elliptical in cross-section 3 X 6 mm in diameter. The fiber orientation is dependent on the height of dens axis, mostly in the cranial caudal direction. In 12 specimens there was a ligamentous connection between dens and lateral mass of the atlas as a part of the alar ligament. In 2 specimens anterior atlanto-dental ligament was identified. The computerized tomographic (CT) images can clearly show alar ligaments in axial, coronal, and sagittal planes. The ligaments limit the axial rotation in the occipito-atlanto-axial complex (to the right by left alar and vice versa) as well as in side bending. The ligament is most stretched, and consequently most vulnerable, when the head is rotated and in addition flexed. This mechanism, common in whiplash injuries, could lead to irreversible overstretching or rupture of the ligaments especially as the ligaments consist of mainly collagen fibers.

Adult↗
PubMed1987

CT-functional diagnostics of the rotatory instability of upper cervical spine. 1. An experimental study on cadavers.

Twelve specimens of the upper cervical spine were functionally examined by using radiography, cineradiography and computerized tomographic (CT) scan. The range of rotation was measured from CT images after maximal rotations to both sides. The left alar ligament was then cut and the examination repeated. The alar and transverse ligaments could be differentiated on CT images in axial, sagittal, and coronal views. Rotation at occiput-atlas was 4.35 degrees to the right and 5.9 degrees to the left and at atlas-axis it was 31.4 degrees to the right and 33 degrees to the left. After one-sided lesion of the alar ligament, there was an overall increase of 10.8 degrees or 30% of original rotation to the opposite side, divided about equally between the occiput-atlas and the atlas-axis. It is concluded that a lesion (irreversible overstretching or rupture of alar ligaments) can result in rotatory hypermobility or instability of the upper cervical spine.

Axis, Cervical Vertebra↗
PubMed1987

CT-functional diagnostics of the rotatory instability of the upper cervical spine. Part 2. An evaluation on healthy adults and patients with suspected instability.

Nine healthy adults and 43 patients with cervical spine injury were examined by using functional (computerized tomography) CT scanning. The ranges of axial rotation at the levels occiput C0-C1, C1-C2, and C2-C3 were measured. A rotation at C0-C1 greater than 8 degrees; at C1-C2, 56 degrees; or a right-left difference C0-C1 greater than 5 degrees and C1-2 greater than 8 degrees indicates hypermobility. A rotation at segment C1-C2 of less than 28 degrees indicates hypomobility. Surgical stabilization of rotatory instability could be considered as a possible therapeutic procedure.

Adolescent↗
PubMed1987

[Diagnosis of hyper- and hypomotility of the upper cervical spine using functional computerized tomography].

At present, there are few methods that are of any assistance in evaluating the ligaments of the upper cervical spine. It is obvious that a lesion of these ligaments could result in instability of the cranial cervical junction. Nine healthy adults and 45 patients with suspected rotatory instability of the upper cervical spine after trauma were examined using functional CT-scans. After CT scans of the upper cervical spine had been obtained with the patient in a neutral position, the head was passively rotated to the left and right and held in these positions by adhesive tape. CT scans were performed for the left and right rotation. The range of axial rotation was measured in relation to the neutral position at the level of the occiput, atlas and axis using identical bony landmarks. A mean rotation of 4.2 degrees to the right and 3.8 degrees to the left was measured at the occiput/atlas level. The mean difference between left and right rotation in individual patients was 2 degrees. The mean rotation of C1-2 was 41.8 degrees to the right and 44.3 degrees to the left. The mean difference between left and right rotation was 2.8 degrees. A 98% confidence interval for allocating a pathological case to the distribution of healthy adults was defined. According to this rule, occiput/atlas rotation of 8 degrees or more, C1-2 rotation of 56 degrees or more, a left/right OCC/C1 difference of 5 degrees or more and a left/right C1-2 difference of 8 degrees or more were considered to be pathological.(ABSTRACT TRUNCATED AT 250 WORDS)

Atlanto-Axial Joint↗
PubMed1987

[Injuries of the cervical spine in Switzerland].

The post traumatic evaluation of patients after soft tissue injuries of cervical spine is not clear. As objective criteria of the injury are often absent, the judgement in the medical expertise is difficult. 1100 medical records as a representative sample of 11,000 patients with cervical spine injury recorded at the Swiss National Insurance Company during the years 1978-81 were analysed. 320 records were evaluated in detail. Those injured received a questionnaire about their present psychosocial situation, complaints, necessity of treatment and financial compensation. 207 or 65% returned the filled out questionnaire. X-rays verified that 12.6% of all injured had fractures or luxation of the cervical spine, 4.2% of all patients showed fracture combined with spinal cord lesion. In 87.4% only soft tissue injury was described. About the half of the accidents were road accidents, the other half occurred during sport, work etc. 30% of the patients with fracture are receiving financial compensation as a result of working disability, 70% of them are still, i.e. 4-7 years after injury, under medical care. Only 1% of the injured patients without fracture are receiving a financial compensation, while 25% of them do need treatment for their symptoms caused by the accident. The therapeutical procedures range from application of Myotonolytics, pain killers, Infiltrations to Physiotherapy and Manipulation. Almost all of those 25% injured are not in agreement with the decision of the insurance company based upon the medical expertise. 12% of all injured developed, after the accident, psychological symptoms, such as decreased concentration, vitality or productivity, melancholy etc. The discrepancy between the judgement of the insurance company based upon the medical records and the patients complaints also 4-7 years after injury as well as the diversification of therapeutical procedures used in the long term patients career are indicating a necessity of prospective study on cervical spine injury.

Cervical Vertebrae↗
PubMed1986

Preferential homogenization between adjacent and alternate subrepeats in wheat rDNA.

DNA from the "non-transcribed spacer" (NTS) of two wheat ribosomal RNA gene (rDNA) clones was sequenced. The regions flanking the internal subrepeat arrays are highly conserved between the two clones; the nucleotide sequence differ by less than one-half percent. In contrast, the consensus sequences of the subrepeats in the two arrays differ by three percent. Mutations unique to each array, yet found in more than one subrepeat of the array, are preferentially found in adjacent and alternate subrepeats. The similarity of the DNA sequences of the flanking regions is consistent with a model of homogenization among rDNA gene units by intergenic conversion. We propose that a different mechanism, preferential conversion between neighboring subrepeats, is largely responsible for the homogenization of subrepeats within an array.

Cloning, Molecular↗
PubMed1986

[Diagnosis of instability of the upper cervical spine by functional computed tomography].

The evaluation by means of functional x-rays, of rotatory instability of the upper cervical spine as a result traumatic or inflammatory destruction of the ligamentous apparatus, is unsatisfactory. Functional CT of the upper cervical spine allows measurement of the segmental rotatory movements. 9 healthy adults and 30 patients were examined after neck injury via functional CT's. A rotation between occiput and atlas greater than 9 degrees, between atlas and axis over 50 degrees, the left-right difference at the level C0/C1 greater than 6 degrees and at the level C1/C2 over 10.5 degrees point to a suspicion of hypermobility or instability.

Adolescent↗
PubMed1979

Results of simulation of non-homogeneous ventilatory mechanics for a patient-computer arrangement.

A model of the ventilatory mechanic system was realised on the MEDA TC 41 analogue computer; it consists of 2 structurally identical compartments, differing in the values of their coefficients. By changing the values of coefficients and the relations between the 2 compartments, it was possible to simulate the non-homogeneity of a real, pathologically-changed system of the body afflicted by disease. Complex resistance loops with phase shifts. identical with those really registered from patients, were realised; this was impossible for models with only 1 compartment. By changing the non-homogeneity of the model., it was possible to simulate the past and future development of the state of the diseased patient with sufficient reliability.

Airway Resistance↗
PubMed1976

Analysis of the human respiratory system in hypoxic and anoxic hypoxia by analogue computer simulation.

The goal of this work is to synthesise a model of an adaptive system of respiration control in man, which could be used for the prognosis of human performance under extreme conditions. The model was partly based on 428 experimental results from hypoxic and anoxic hypoxia. Simulation of the oxygen regulatory circuit was realised on the NADAC 100 and MEDA T 80 analogue computers with satisfactory results. Equations constituting a new version of the model are presented in some detail, together with the results of the simulation of ventilatory mechanics.

Computers, Analog↗