Nontraumatic glenohumeral instability and coracoacromial impingement in swimmers

Competitive swimming is one of the most demanding and time-consuming sports. Swimmers at elite level practice 20–30 h per week. During 1 year's practice, the average top level swimmer performs more than 500,000 stroke revolutions per arm. These innumerable repetitions over many years of hard training together with an increasing muscular imbalance around the shoulder girdle seem to be the main etiological factors in the development of the overuse syndrome swimmer's shoulder. Shoulder pain in swimmers has in general been regarded as synonymous with coracoacromial impingement, i.e. anterior shoulder pain due to rotator cuff tendinitis, but new knowledge suggests that a concomitant glenohumeral instability plays an additional role. The diagnostic complexity of the problem is as challenging as the search for the gold standard of treatment. The condition should ideally be diagnosed as early as possible, and intensive functional rehabilitation of the shoulder girdle including the scapular muscles should be started in order to restore muscle balance. The surgical possibilities include subacromial decompression in cases of purely mechanical impingement. If a painful glenohumeral instability persists after intensive functional rehabilitation, anterior capsulolabral reconstruction can be performed. Still, however, short- and long-term results show that surgery is less successful in elite athletes involved in overhead sports. Prevention protocols include education of coaches in primary injury prophylaxis and the institution of resistance strength training in prepubescent swimmers. Emphasis should be made to improve muscular balance around the glenohumeral and scapulothoracic joints.     

The biomechanics of vibration and low back pain

This work is a review of the mechanical factors related to low back pain production in a vibration environment. The sitting posture is an extreme orientation for the lumbar intervertebral disc that 1) increases its internal pressure, 2) increases its anteroposterior shear flexibility, while: 3) decreasing its resistance to buckling instability and 4) stressing the posterior region of the disc. Vibration is an additional mechanical stressor. Several studies suggest that the following preventive measures be taken to reduce the risk of low back pain due to driving: 1) minimize the vibration reaching the driver, 2) avoid lifting or bending immediately following driving, and 3) walk around for a few minutes following driving. © 1993 Wiley-Liss, Inc.     

Primary orthostatic tremor is an exaggeration of a physiological response to instability.

Primary orthostatic tremor (POT) is a rare disorder characterised by an intense sense of unsteadiness upon standing and a 16-Hz tremor in which the timing between tremor bursts in different muscles (unilateral and bilateral) remains constant. Hitherto, similar EMG activity has not been described in healthy subjects and it has been postulated that the oscillations seen in POT are primarily pathological. In this study, EMG was recorded from tibialis anterior in healthy subjects who were made unsteady through vestibular galvanic stimulation or leaning backwards. Under these conditions, a peak at approximately 16 Hz was seen in the coherence between the left and right tibialis anterior. This bilateral coherence was absent when the subjects activated the same muscles when not unsteady. These data indicate the existence of a physiological system involved in organising postural responses under circumstances of imbalance and characterised by a highly synchronised output at approximately 16 Hz. In addition, the results suggest that the core abnormality in POT may be an exaggerated sense of unsteadiness when standing still, which then elicits activity from a 16-Hz oscillator normally engaged in postural responses.     

Executive cognitive deficits in primary dystonia.

Primary dystonia is a disorder of movement for which no consistent pathophysiology has been identified; in the absence of evidence to the contrary, it is assumed to be cognitively benign. We have studied a clinically heterogeneous group of 14 patients with primary dystonia on a battery of neuropsychological tests. Despite well-preserved speed of information processing, language, spatial, memory and general intellectual skills relative to normal controls, we have identified a constellation of attentional-executive cognitive deficits on the Cambridge Neuropsychological Test Automated Battery (CANTAB). Specifically, patients demonstrated significant difficulties negotiating the extra-dimensional set-shifting phase of the IED task. The implications of these findings for the pathophysiology of primary dystonia are discussed. This is, to the best of our knowledge, the first report of a significant cognitive deficit in patients with primary dystonia.     

Pulpal reactions to glutaraldehyde and paraformaldehyde pulpotomy dressings in monkey primary teeth

Abstract Pulpotomy was performed in primary teeth of 4 vervet monkeys to compare the effect of an experimental dressing containing glutaraldehyde (GL) to a similar formula with paraformaldehyde (PF). Forty teeth were examined histologically 2 weeks to 5 months post-operatively. In the PF group, calcifications were more frequently observed and the central core of tissue in the root canal was heavily laden with debris. Pathologic apical resorption and lesions were more frequent. The pulp in the apical third of the root canal was usually uninflamed in the GL group and peripheral calcifications were seldom observed in it. Reaction to GL seemed, therefore, more favorable clinically. Defects were not observed in the permanent teeth that erupted following shedding or extraction of the experimental primary ones of either group.     

Klinefelter's Syndrome: Hypogonadism,abnormal carbohydrate metabolism. Is it a result of biotin deficiency?

The aetiology of Klinefelter's Syndrome is not known. The causative factor(s) must explain the hypogonadism, low androgen levels, the disordered carbohydrate metabolism and the commonly associated psychiatric conditions. A biotin deficient/dependent state can account for the above. A biotin deficient Klinefelter's Syndrome patients with the above is described. The possible role of biotin in the primary, secondary and tertiary prevention of Klinefelter's Syndrome needs further research.     

Guidance of dopaminergic neuritic growth by immature astrocytes in organotypic cultures of rat fetal ventral mesencephalon.

Astrocytes, with their many functions in producing and controlling the environment in the brain, are of great interest when it comes to studying regeneration after injury and neurodegenerative diseases such as in grafting in Parkinson's disease. This study was performed to investigate astrocytic guidance of growth derived from dopaminergic neurons using organotypic cultures of rat fetal ventral mesencephalon. Primary cultures were studied at different time points starting from 3 days up to 28 days. Cultures were treated with either interleukin-1 beta (IL-1 beta), which has stimulating effects on astrocytic proliferation, or the astrocytic inhibitor cytosine arabinoside (Ara-C). Tyrosine hydroxylase (TH)-immunohistochemistry was used to visualize dopaminergic neurons, and antibodies against glial fibrillary acidic protein (GFAP) and S100 beta were used to label astrocytes. The results revealed that a robust TH-positive nerve fiber production was seen already at 3 days in vitro. These neurites had disappeared by 5 days. This early nerve fiber outgrowth was not guided by direct interactions with glial cells. Later, at 7 days in vitro, a second wave of TH-positive neuritic outgrowth was clearly observed. GFAP-positive astrocytic processes guided these neurites. TH-positive neurites arborized overlying S100 beta-positive astrocytes in an area distal to the GFAP-positive astrocytic processes. Treatment with IL-1 beta resulted in an increased area of TH-positive nerve fiber network. In cultures treated with Ara-C, neither astrocytes nor outgrowth of dopaminergic neurites were observed. In conclusion, this study shows that astrocytes play a major role in long-term dopaminergic outgrowth, both in axonal elongation and branching of neurites. The long-term nerve fiber growth is preceded by an early transient outgrowth of dopamine neurites.     

Lymph node metastases in the neck and parotid gland from an unknown primary melanoma

A lymph node metastasis in the neck or parotid region from an unknown primary melanoma is an uncommon occurrence. Out of a total of 300 patients with head and neck melanoma treated at the Netherlands Cancer Institute between 1976 and 1992, 17 (5.7%) presented in this way. The most common site for metastatic lymph nodes (18 nodes in 17 patients) was level V (n= 7), followed by the parotid region (n= 4), level II (n= 4), level III (n= 2), and level IV (n= 7). Two patients had local excision of the neck node metastasis only, while the remaining 15 patients underwent more extensive surgical treatment. The 5-year disease-specific survival rate in this group was 48%, with a median survival of 36 months, which is more or less similar to the prognosis of stage II melanoma of the head and neck with a known, surgically treated primary tumour. No relation was found between disease-free interval and sex, the number of positive lymph nodes or the duration of symptoms.     

Primary Aldosteronism

ABSTRACT A follow-up examination was performed one month to 20 years after adrenalectomy in 28 cases with surgically treated primary aldosteronism due to adrenal adenoma. The mean age at diagnosis was 45, and the mean duration of hypertension seven years. Severe hypertension with a diastolic blood pressure of 130 mmHg or more was observed in 35%. Postoperatively cerebrovascular catastrophe developed in two cases, both of which belonged to the group of patients with severe hypertension. Normalization of blood pressure was observed in 70% and in the remaining subjects the blood pressure was lower than at diagnosis. The blood pressure response to adrenalectomy appeared unpredictable in view of such parameters as the initial blood pressure, age at diagnosis, and duration of the hypertensive state. Toxicosis during pregnancy and metrorrhagia was observed with unexpectedly high frequency in this study population. Low ambulatory plasma renin activity was recorded at the follow-up in 15 out of 18 subjects studied in the absence of evidence of hyperaldosteronism.     

Effect of mite-impermeable mattress encasings and an educational package on the development of allergies in a multinational randomized, controlled birth-cohort study – 24 months results of the Study of Prevention of Allergy in Children in Europe

BACKGROUND: Sensitization to house dust mite (HDM) is an important risk factor for the development of asthma and allergic disease in childhood. Higher levels of HDM allergen are linked to increased sensitization to HDM. OBJECTIVE: To study the effect of mite-impermeable mattress encasings and an educational package on the development of allergies in a newborn cohort. METHODS: Six hundred and ninety-six newborns at high risk of developing allergies were enrolled in three European countries (Germany, Austria, UK) in a prospective, randomized, controlled birth-cohort study. Children were randomly assigned to an intervention and control group. Intervention measures included the use of mite-impermeable mattress encasings for the child's bed and a simple educational package on allergen avoidance. The control group received basic information about allergies. Children were followed up at age 6, 12, 18 and 24 months. RESULTS: 80.9% of the children were followed up to the age of 24 months. No difference in the prevalence of sensitization to HDM (control vs. intervention group: 8.4% vs. 6.1%, P=0.33) or the development of symptoms (recurrent wheezing 10.3% vs. 10.7%, nocturnal cough 12.5% vs. 12.5%) or allergic diseases (asthma 3.5% vs. 5.1%, eczema 20.0% vs. 19.6%, rhinitis 28.9% vs. 25.8%) could be found between the control and intervention group. CONCLUSION: In this study, HDM avoidance did not show a protective effect on the development of sensitization to HDM or symptomatic allergy in children at age 24 months.