Neck and shoulder complaints among sewing-machine operators: a study concerning frequency, symptomatology and dysfunction

The occupation of sewing-machine operators (SMO) involves monotonous and repetitive tasks, performed in a work position equivalent to a static component of muscular load on the neck and shoulder. The present study concerns the occurrence of neck-shoulder problems in a population of SMO. A total of 224 SMO from four textile factories in the western part of Sweden were subjected to a comprehensive questionnaire about demographic, vocational, medical and psychosocial data. The Nordic Ministry Questionnaire specifically directed towards neck-shoulder complaints showed a prevalence rate during the last 12 months of 75% and during the last seven days a rate of 51%. Daily problems were experienced by 26%. Some 27% had had problems leading to restraints in work time and 37% in leisure time. Those SMO screening positive were clinically examined in an attempt to describe the clinical picture behind the complaints. Diagnoses were made according to specific criteria. The tension neck syndrome (TNS) was most frequent, followed by the cervical syndrome. In half of those examined, symptoms and findings were too unspecific for diagnosis. A positive correlation between the TNS and working hours per week suggests a daily prolonged static load on the neck and shoulder to be of importance for neck-shoulder problems among the SMO.

Hormonal regulation of a rat seminiferous tubule factor which inhibits LH action on interstitial cells

The cytosol from rat testes or seminiferous tubules contains a factor that markedly reduces the responsiveness of interstitial cells to stimulation by LH. It was noted previously that the inhibitor cannot be found until 35 days of age, suggesting that gonadotrophic stimulation of the testes is of importance for its formation. In the present studies, treatment of intact 20-day-old rats with FSH or with a combination of FSH and LH caused a premature appearance of the inhibitory activity. LH alone had a weak effect. However, hypophysectomy at 20 or 35 days of age did not influence the inhibitor content of the testes. Moreover, when the Leydig cells of adult rats were destroyed selectively by treatment with ethylene dimethane sulphonate, inhibitor levels were unchanged. It is suggested that induction of the Leydig cell inhibitor is under the control of FSH. However, once induced, its regulation seems to be independent of the pituitary gland. In separate experiments, ligation of the efferent ducts of the testes in adult animals did not cause any accumulation of inhibitory activity in the ligated testes, nor could the inhibitor be traced in the caput epididymis. Thus, it does not seem to be secreted into the epididymis, but rather may act as a paracrine factor in the testis.

Mechanism of action of the factor(s) secreted by rat seminiferous tubules and inhibiting interstitial cell testosterone production in vitro

Rat seminiferous tubules secrete a factor which inhibits LH-dependent steroidogenesis by interstitial cells. The inhibitory activity was found to be specific for the testes, as cytosols from other rat tissues such as the kidney, heart, spleen, liver and epididymis had no significant effect on testosterone production by interstitial cells. Preliminary characterization by Ultrogel AcA 44 gel chromatography demonstrated that the active substance in SMST has a molecular weight between 40-50 kD. Spent medium from incubation of seminiferous tubules (SMST) caused a dose-dependent inhibition of LH-or cholera toxin-stimulated in vitro testosterone production by rat interstitial cells. However, SMST failed to inhibit forskolin-stimulated steroidogenesis. The effect of SMST was not altered by pre-incubating the cells with the sulfhydryl reagent, N-ethylmaleimide. Considering the proposed mode of action of these modulators of adenylate cyclase activity, the present studies suggest that a high molecular weight testis specific factor acts through the guanine nucleotide-binding stimulatory regulatory protein of the adenylate cyclase complex to inhibit LH-dependent testosterone production by Leydig cells.

Ontogeny and cellular origin of an interleukin-1-like factor in the reproductive tract of the male rat

We have recently isolated an interleukin-1 (IL-1)-like factor from the rat testis, which originates from the seminiferous tubules and is a protein with an MW of 17,000 and a pI of 5-6. This paper reports on the appearance of the IL-1-like factor during postnatal development and investigates its cellular origin further. IL-1 activity was measured by a murine thymocyte proliferation assay. Very low IL-1 activity was present in culture medium conditioned by seminiferous tubules from rats aged 10 or 20 days. From 30 days of age, increasing amounts were detected, reaching a maximum level in adult animals (60-90 days). No IL-1 activity was found in medium conditioned by peritubular cells. Sertoli cell-enriched seminiferous tubules obtained from experimentally cryptorchid or from prenatally irradiated rats produced much higher levels of IL-1 activity than did those obtained from intact testes. IL-1 activity was detected in efferent duct fluid after ligation of the efferent ducts for 24 h, indicating that the IL-1-like factor was secreted into the tubular lumen. Low levels of IL-1 activity were detected in extracts of epididymal tissue and epididymal sperm, whereas ejaculated seminal plasma, seminal vesicle fluid and extracts of seminal vesicles (together with the coagulating glands) and ventral and dorsolateral prostate lacked IL-1 activity. Instead, seminal plasma inhibited testicular IL-1 activity dose-dependently without affecting cell viability in the thymocyte cultures. Although its biological function remains to be defined, our results indicate that the testicular IL-1-like factor is produced by Sertoli cells and that its appearance during development coincides with the initiation of active spermatogenesis in the rat testis.

Ontogeny and cellular origin of a rat seminiferous tubule factor(s) that inhibits LH-dependent testosterone production by interstitial cells in vitro

Previous studies have shown the presence of a peptide in spent media from incubated seminiferous tubules (SMST), which inhibits LH stimulation of testosterone production by rat Leydig cells in vitro. The present study has investigated whether the secretion of this inhibitor changes during development in the rat. Seminiferous tubules obtained from rats aged 10, 20, 25, 30, 35, 40, 42, 50 or 60 days were incubated at 32 degrees C for 24 h. Spent media from these incubations were then added to interstitial cells isolated from the testes of rats aged 60 days. Spent media from rats aged 10-30 days had no effect on basal or oLH-stimulated testosterone production by interstitial cells during 3-h incubation. Significant inhibition of LH-stimulated testosterone production was, however, observed with SMST from rats aged 35-60 days. Spent media prepared using tubules from normal, prenatally irradiated (Sertoli cell-enriched) or seminiferous tubules, depleted of peritubular cells, had no effect on basal, but inhibited LH-stimulated, testosterone production. Spent media from peritubular cell cultures had no effect on basal or LH-stimulated testosterone production by interstitial cells. The inhibitory effect of SMST was also dependent on the age of the rats providing the target cells. Interstitial cells from rats aged 10, 20, 50 or 60 days were responsive to the inhibitor while cells from rats aged 30 and 40 days were not. The results of the present study demonstrate that the seminiferous tubule factor(s), which inhibits LH action on interstitial cells, is first secreted at 35 days, a time when the most mature germ cells present are in the early maturation phase. Moreover, interstitial cells are responsive to this factor in both immature (10-20 day-old) and mature (50-60 day-old) rats, but not at ages in between these times. It is suggested that the adult Sertoli cell is the major source of the interstitial cell inhibitor.

The rat testis produces large amounts of an interleukin-1-like factor

Homogenates of whole testis, isolated seminiferous tubules, testicular cytosol, conditioned media from seminiferous tubules obtained from intact or cryptorchid rats, as well as seminiferous tubules devoid of peritubular cells, showed high concentrations of interleukin-1 (IL-1). Cytosol from spleen showed low IL-1 activity, while no activity was found in cytosol from heart, kidney, prostate, ovary or liver. Interleukin-1 activity was not detected in spent medium from cultures of immature Sertoli cells (10-day-old rats) or from peritubular cells or in homogenates of interstitial cells from adult rats. Ultrogel AcA 44 gel chromatography and HPLC size exclusion chromatography exhibited a single peak of IL-1 activity corresponding to a relative molecular mass of 17,000-20,000 (Mr = 17-20 K). Similarly, chromatofocusing revealed only one peak of activity with an apparent isoelectric point of 5-6. It is concluded that the rat testis contains large amounts of an IL-1 alpha-like factor. The adult Sertoli cell or possibly germ cells are suggested as its primary source. Testicular IL-1-like activity is of particular interest in view of the intense cell proliferation during spermatogenesis, and the tendency to testicular relapse of acute lymphoblastic leukaemia.

Characterization of the calf uterine androgen receptor and its activation to the deoxyribonucleic acid-binding state

The androgen receptor (AR) from calf uterine cytosol has been studied in terms of steroid-binding affinity, hormone dissociation kinetics, and DNA-cellulose-binding capacity. The binding affinity for three androgens, analyzed under conditions where binding to progesterone receptor did not occur, decreased in the order: methyltrienolone greater than 5 alpha-dihydrotestosterone greater than testosterone. Activation of the receptor to the DNA-binding state involved the following changes of the receptor: decrease in dissociation rate for the steroid, disaggregation of the receptor, and increase in affinity for DNA. Dissociation studies with methyltrienolone and 5 alpha-dihydrotestosterone revealed that the AR can exist in two affinity states which differ 13- to 30-fold in their affinity for the steroid. Molybdate (10-20 mM) prevented the formation of the high affinity state. The high affinity state receptor was formed in the absence of molybdate or after ammonium sulfate precipitation (0-40% saturation) of the molybdate-stabilized low affinity state receptor. During formation of the high affinity state, the sedimentation coefficient of the receptor in low ionic strength buffer decreased from 8-9S to 4.5S, indicating receptor disaggregation. DNA-cellulose binding capacity increased from 3 to 65% upon formation of the high affinity state. The DNA-binding form could be eluted from DNA-cellulose at 0.14 M NaCl. After elution the DNA-binding form maintained its sedimentation coefficient of 4.5S and chromatographed as a protein with a Stokes radius of 44 A. From these results it can be concluded that the activated, DNA-binding form of the AR in calf uterus is a protein with a molecular mass of approximately 85,000, which acquires a higher affinity for the ligand upon its formation.

The effect of sagittal curve changes on brace correction of idiopathic scoliosis

In bracing of idiopathic scoliosis, the corrective components of the brace have been evaluated regarding axial and lateral forces. The present study stresses the importance of sagittal changes achieved in patients wearing the brace. The corrective effect on scoliotic curves by sagittal changes of the spine in bracing is demonstrated by roentgenograms.

Energy expenditure during walking in patients with scoliosis. The effect of the Milwaukee brace

Oxygen uptake during treadmill walking was measured in 8 scoliotic patients with idiopathic curves ranging from 25 to 60 degrees. The patients were fitted with a Milwaukee brace and the test was repeated within 2 or 3 days to study the effect of the brace on energy expenditure, mechanical work, and ventilatory function. The total oxygen uptake was not systematically affected by wearing the brace. When the weight of the brace was included, the oxygen uptake/kg body weight decreased in most of the patients at low walking speed in spite of an increased lift work. The positive influence on energy expenditure was interpreted as a stabilizing effect of the brace on the spine. This effect was not consistent at moderate and high speeds of locomotion, where both a decrease and an increase in oxygen uptake/kg were observed. Heart rate increased significantly during walking at high speed with the brace, while a slight but significant reduction of the tidal volume was found during walking at low speed.

Energy expenditure during walking in patients with scoliosis. The effect of surgical correction

Oxygen uptake during treadmill walking was measured in 43 female patients with scoliosis, aged 11 to 32 years. The majority of the patients had idiopathic thoracic curves, ranging from 25 to 160 degrees. The study included variables such as trunk imbalance, heart rate, step frequency, and respiratory data. Compared to age- and sex-matched controls, the scoliotic patients showed a significantly higher oxygen uptake/kg body weight and higher heart and respiratory rates. There was a negative correlation between the oxygen uptake/kg and the vital capacity. Trunk imbalance or palvic obliquity, measured from standing radiograms, did not correlate with energy expenditure, nor did the degree of the curvature. Twenty-eight of the patients underwent surgical correction and fusion of the spine with the Harrington technique. Two years after surgery, these patients showed a mean decrease in oxygen uptake/kg, significant at low walking speeds but not at high velocities. A decrease in oxygen uptake/kg was related to an increase in vital capacity. A correlation between a lowered oxygen uptake/kg and a gain in weight was observed.

Lung volumes in scoliosis before and after correction by the Harrington instrumentation method

Studies of static lung volumes were performed before and after surgery in 92 scoliotic patients, aged 10 to 25 years. The majority of the patients had idiopathic dorsal curves. Vital capacity, total lung capacity, functional residual capacity and residual volume were measured at least 18 months after surgery. A significant increase was observed in all static volumes, averaging 10 per cent; the pre- and postoperative values were expressed in per cent of predicted normal values according to age and height. Correction of body height was taken into consideration in the prediction of normal values. Patients with the more advanced scoliosis had the greatest improvement in lung volumes. The patients were treated postoperatively with a Milwaukee brace for an average of 15 months. The use of this brace, which allows for chest expansions, might account for the improved lung function compared to previous series where plaster body jackets were used. Thus the correction of idiopathic scoliosis by the standard posterior fusion with Harrinton instrumentation together with our postoperative routine provides a lasting reduction of the spinal deformity, prevents progression of respiratory impairment and, in fact, increases the lung volumes, vital capacity, total lung capacity and functional residual capacity by an average of 10 per cent.

Respiratory impairment and airway closure in patients with untreated idiopathic scoliosis

Fifty patients aged 11 to 78 years with untreated idiopathic scoliosis were studied. An increased frequency of respiratory impairment was found, especially in patients with a severe degree of scoliosis. Seven patients under 60 years were unable to work and all had thoracic curves exceeding 100°. None of the patients between 20 and 65 years of age was engaged in hard work and 22% had a disability pension, all because of respiratory impairment. A tendency to increased shortness of breath was noted with increasing curves as well as age.

Dynamic and static spirometry was performed and airway closure was studied with the xenon-133 bolus technique. With increasing degrees of scoliosis there was a reduction in all lung volumes. Seventeen of 40 patients showed evidence of airway closure at lung volumes greater than functional residual capacity; 6 of these patients were under 40 years of age, and all had thoracic scoliosis exceeding 90°.