Cytogenetic and histological studies of the brook trout, Salvelinus fontinalis (Mitchill), and the Arctic char, S-alpinus (L.) hybrids

Although brook trout and the Arctic char hybrids are able to reproduce, individuals with decreased fertility or even fish that are unable to produce any gametes have been also described. Abnormal gonadal development and disturbances in the gamete production in the char hybrid offspring may be triggered by the odd chromosome number and disturbances in their pairing during meiosis. To verify this hypothesis, cytogenetic examination and the gonadal histology analysis of the brook trout x Arctic char hybrids were carried out. Diploid chromosome number in the studied char (F-1) hybrids varied from 82 to 84 (FN = 99-102). Among 28 hybrids, 12 males, three females, nine intersex individuals and two sterile specimens were described. In the case of two individuals, gonads were not found. Diploid chromosome numbers in the males and intersex individuals varied from 82 to 84. Chromosome numbers in the females were 82 and 83 chromosomes. Two sterile fish exhibited karyotypes composed of 82 and 84 chromosomes. Predominance of the ovarian component in the intersex gonads and gonadal sex ratio distortion towards the males suggested hybrid females had problems with gonadal differentiation. However, the lack of the clear relationship between chromosome number and gonadal development in the studied hybrids did not support our hypothesis that odd chromosome number may be responsible for such reproductive disturbances in the hybrid individuals. We have presumed that sterility and intersexual development of the gonads may be caused by interactions between brook trout and Arctic char genes on the sex chromosomes and autosomes rather than unpairing of the parental chromosomes.Polish National Science Center (NCN) [N N311 525240]info:eu-repo/semantics/publishedVersio

The Importance of Resilience and Level of Anxiety in the Process of Making a Decision about SARS-CoV-2 Vaccination

People’s opinions on immunization are diverse. Despite the constant improvement of vaccine formulas, the number of people reluctant to immunize is not decreasing. The purpose of our study is to assess the psychological determinants of immunization reluctance in depth. We measured levels of anxiety (death-related and general), fear of COVID-19, self-esteem and resilience among 342 adults. We found that the level of COVID-19 related fear is higher among the vaccinated population, despite general anxiety levels being lower. Surprisingly we didn’t find significant differences in resilience and self-esteem levels. Findings are concurrent with previous research—COVID-19 related fear level is higher among vaccinated people. Resilience and self-esteem are defined as stable, trait-like constructs, and thus may not manifest higher levels in very specific pandemic situations, although they may lower the levels of general anxiety

Complex elbow Instability: treatment and rehabilitation

Complex elbow instability represent a challenging injury even for expert elbow surgeons. Chronic instability, posttraumatic osteo-arthritis, stiffness and poor functional outcomes are frequent if these injuries are not adequately treated. A correct preoperative evaluation includes X-rays, CT scan with 2D and 3D reconstruction and stability tests under fluoroscopy in order to recognize all osseous and ligamentous lesions. The most common patterns of complex elbow instability includes: (1) radial head fractures associated with lateral and medial collateral ligaments lesions; (2) coronoid fractures and lateral collateral ligament lesion; (3) Terrible Triad; (4) fracture-dislocations of the proximal ulna and radius, also referred to as transolecranon fracture-dislocations and Monteggia-like lesions; and (5) humeral shear fractures associated with lateral and medial collateral ligament lesions. The main goals of the treatment are (1) to perform a stable osteosynthesis of all fractures, (2) to obtain concentric and stable reduction of the elbow throught the repair of soft tissue constraint lesions and (3) to allow early motion. All the patterns of complex elbow instability share the same therapeutic algorithm based on seven main principles: 1) the proximal ulna must be anatomically reduced and fixed; 2) the radial head or humeral shear fracture must be repaired or replaced, 3) bone length, alignment and rotation of ulnar and radial shaft fractures must be recovered; 4) the lateral collateral ligament complex must be repaired to obtain elbow stability; 5) the medial collateral ligament must be repaired if persistent instability is observed after lateral collateral ligament repair; 6) an hinged external fixator must be considered if the elbow remains unstable or the protection of the joint reconstruction is required; 7) re-evaluation of the surgical steps if congruent ulno-humeral and radio-humeral joints have not been achieved. Following the surgical treatment an adequate rehabilitation programme should be started promptly and continued for at least 6 months since a significant improvement of the range of motion occurs prevalently in this period, which should be considered the critical time period to obtain a functional elbow