Inpatient hospital care for back disorders in relation to industry and occupation in Finland

OBJECTIVES: The variation in hospital admission rates was studied for back disorders by industry and occupational title among gainfully employed Finns. METHODS: Admissions to Finnish hospitals in 1996 among 25- to 64-year-olds, based on the Hospital Discharge Register, were linked with sociodemographic data from the 1995 population census for the following primary diagnoses [International Classification of Diseases, 10th revision (ICD-10)]: all back disorders (M40.0-54.9; N (individual patients) 7,253), lumbar intevertebral disc disorders (M51.0-M51.9, N = 3,863), and other common back disorders (ICD-10: M47.1-47.2, M47.8-47.9, M48.0, M54.1, M54.3-54.5, M54.8-54.9; N = 2,433), with the total occupationally active workforce (same age range and gender) as reference. Age-standardized hospitalization rate ratios (SRR) were calculated. RESULTS: The highest SRR values for hospitalization for any back disorder were found for fishing (SRR 195), "other" mining and carrying (SRR 168), and sewage and refuse disposal (SRR 152) among the men and water transport (SRR 158), wood product (SRR 149) and pulp, paper and paper product (SRR 145) manufacturing among the women. Computer activities (SRR 44) among the men and insurance and pension funding (SRR49) among the women had the lowest SRR values. The occupations reindeer breeders and herders (SRR 495), agricultural workers (SRR 232), and paper product workers (SRR 205) among the men and plastic product (SRR 233), laundry (SRR 224), and agricultural (SRR 219) workers among the women had the highest SRR values. The lowest SRR values were observed for upper white-collar employees in public administration [men (SRR 40) and women (SRR 61)]. CONCLUSIONS: Hospitalization rates for back disorders were high for several physically strenuous industries and occupations.     

Cancer incidence among Finnish farmers, 1979-93

A cohort of approximately 120,000 male and 85,000 female farmers registered in the Farm Register of Finland was followed-up for cancer incidence through the Finnish Cancer Registry in 1979-93. Nearly 17,000 cancer cases were observed. Compared with the total cancer incidence of the Finnish population, both genders experienced a 17 to 18 percent decreased risk of cancer. The risks were low in smoking-related cancers, cancers associated with an urbanized way of life, and cancers inversely associated with multiparity. The only cancer sites showing significantly raised standardized incidence ratios (SIR) were lip cancer (SIR=1.51, 95 percent confidence interval [CI]=1.35-1.66) and Hodgkin's disease (SIR=1.35, CI=1.08-1.67) in males. Poisson regression was used in working out the roles of the size and type of farm after adjustment for gender, age, and geographic location of the farm. Risk of Hodgkin's disease was highest in farms without animals (SIR=1.74, CI=1.12-2.59). Multiple myeloma was found in excess among farmers on pig or poultry farms but not on other types of farms.     

Splenectomy and adoptive cell transfer reveal a prominent role for splenic memory lymphocytes in the development of chronic relapsing experimental autoimmune encephalomyelitis

We previously reported that acute experimental autoimmune encephalomyelitis (EAE), induced by active immunization of SJL mice, could be converted into chronic relapsing EAE (CR-EAE) by a pretreatment with neuroantigen and killed mycobacteria 2 months earlier. This finding indicates that immune memory, established by the pretreatment, influences the subsequent EAE induction. The present study shows that splenectomy and lymphadenectomy, applied 1 week before the subsequent active immunization of the pretreated mice, efficiently abort the chronic nature of CR-EAE. Furthermore, we have found that adoptive transfer of lymphocytes from the spleen (but not of those from the local draining lymph nodes) of the pretreated mice to naive syngeneic recipients 1 week before the acute EAE-induction immunization results in the development of CR-EAE. On the other hand, the transfer of lymphocytes from the local draining lymph nodes aggravates the acute disease. These data support a critical role for immune memory of the previous suboptimal challenge in the development of chronic relapsing demyelinating disease.     

Typing of herpes simplex virus isolates with monoclonal antibodies and by nucleic acid spot hybridization

Fifty-one clinical isolates of herpes simplex virus (HSV) were typed by an enzyme immunoassay (EIA) using mouse monoclonal antibodies, by DNA spot hybridization, and by restriction enzyme analysis using restriction endonuclease Eco RI. Extracts of VERO cells infected with the isolates were used for coating microtitre plates or denatured and spotted onto nitrocellulose filters. Viral antigens passively adsorbed to microtitre plates were detected by an indirect EIA using mouse monoclonal antibodies specific for HSV type 1 (HSV-1) or HSV type 2 (HSV-2). Spotted DNA was hybridized with 32P-labeled probes containing Hind III/Sal I-fragments of either HSV-1 or HSV-2 DNA and bound radioactivity was detected by autoradiography and counted in a liquid scintillation counter. All the three methods gave identical results for the 51 isolates studied. Twenty-six isolates were identified as HSV-1 and 25 as HSV-2. An additional 30 specimens were tested only by EIA and hybridization. Results by both techniques were in complete agreement.     

Pseudosynovial fluid from loosened total hip prosthesis induces osteoclast formation

Interface tissue between the bone and loosening total hip implant is acidic and highly osteolytic. It is characterized by the formation of cathepsin K positive foreign body giant cells. Similar structures to those found in the normal joint surround the artificial hip joint. Cells in synovial membrane of the artificial hip generate synovial fluid that is called pseudosynovial fluid. Interface tissue fibroblasts are able to produce receptor activator of NF-kappaB ligand (RANKL), which can induce osteoclastogenesis during the loosening process. Western blot analysis indicated that RANKL is present in the pseudosynovial fluid. Pseudosynovial fluid induced cultured peripheral blood mononuclear cells to form multinuclear TRAP positive giant cells. In the presence of osteoprotegerin, the soluble RANKL decoy receptor, the number of TRAP positive multinuclear cells was reduced to half (p < 0.05). The multinuclear cells induced with pseudosynovial fluid contained active cathepsin K protein and were capable of bone matrix resorption in vitro. The cells were shown to express osteoclast phenotype markers, such as mRNA for cathepsin K, TRAP, and calcitonin receptor. It is therefore apparent that pseudosynovial fluid from patients with aseptic loosening of total hip prosthesis contains a potent osteoclastogenic factor RANKL that further suggests a favorable environment for osteoclast formation in the peri-implant tissues. It is thus concluded that suppression of RANKL activity may be beneficial in terms of increasing the lifetime of total hip prostheses.     

Increased nitric oxide synthase-3 expression in kidneys of deoxycorticosterone acetate-salt hypertensive rats.

In addition to its hemodynamic effects, nitric oxide (NO) may play a role in the renal tubular handling of sodium. Experiments were conducted to determine possible changes in renal nitric oxide synthase-3 (NOS3) expression in rats treated with deoxycorticosterone acetate (DOCA) and high salt. All rats were uninephrectomized, and either a placebo or DOCA pellet was implanted subcutaneously. Placebo-treated rats were then given tap water to drink ad libitum, and DOCA-treated rats received a 0.9% NaCl solution to drink. Once a week, rats were placed in metabolic cages so that a 24-h urine sample could be collected. After 3 wk, the animals were sacrificed and the kidneys removed and prepared for subsequent immunohistochemical or Western blot analysis. Urinary excretion of nitrate and nitrite (NOx) was measured to provide an indication of the intrarenal production of NO. DOCA-salt hypertensive rats exhibited increased urinary NOx excretion (2.43 +/- 0.48 micromol NOx/mg creatinine) compared with the placebo control animals (1.17 +/- 0.06 micromol NOx/mg creatinine). Western blot analysis revealed that NOS3 protein levels in both the cortex and medulla were greater in DOCA-salt rats compared with placebo-treated animals. Immunohistochemical analysis of kidneys revealed that NOS3 expression in placebo rats was localized in vascular endothelial cells with slight, but detectable, immunoreactivity in medullary collecting ducts. In DOCA-salt rats, a very large increase in the intensity of immunostaining was detected in tubular epithelia of the proximal tubule, thick ascending limb of Henle's loop, and cortical and medullary collecting duct; immunoreactivity in endothelial cells appeared unchanged. These data suggest that increased tubular expression of NOS3 is responsible, at least in part, for the increased renal production of NO in DOCA-salt hypertension, and are consistent with a role for NO in the renal tubular response to salt loading.     

CILIARY BEAT FREQUENCY AT SIX LEVELS OF THE RABBIT AND RAT RESPIRATORY TRACT IN COW, DOG, GUINEA-PIG, PIG

1. The ciliary beat frequency (CBF) of six animal species from six regions of the respiratory tract were measured: inferior turbinate, nasopharynx, the upper part of trachea from first to second cartilage, the lower part of trachea, main bronchus and subsegmental bronchi. Cow, pig, dog, rabbit, guinea-pig and rat were studied. 2. There were no significant differences in the CBF values between cow, pig and dog, and the ciliary activity was essentially the same (11.3-16.9 Hz) in all parts of the respiratory tract. 3. In the rat, the CBF was slower, especially in subsegmental bronchi (6.8 Hz). 4. In general, CBF was higher in upper than lower airways, with the exception of guinea-pig. 5. Signal quality was the highest in guinea-pig tissue, whereas rat tissue produced the signal with the widest variation in CBF and the highest proportion of distorted waveforms. 6. Therefore, for studying drug effects on ciliary activity, guinea-pig seems to be a more suitable animal than the more commonly used rabbit or rat. In drug comparisons, the same part of the respiratory tract and the same animal species should be used.     

Membrane protein antigens in multiple sclerosis

Rabbits were immunized with white matter (WM) membrane fractions isolated from autopsy brain specimens of three patients with multiple sclerosis (MS), and three controls. All the rabbits developed high serum antibody titers to the MS and control WM fractions, as tested by enzyme immunoassay. Antibodies against WM membrane components were analyzed further by immunoprecipitation of radiolabeled WM proteins and subsequent polyacrylamide gradient gel electrophoresis. Antigenic membrane components with molecular weights of 138 000, 111 000, 86 500, 79 600, 69 000, 63 000, 58 000, 53 400, 45 700, 24 500 and 22 300 were found in both MS and control WM. Although there may have been some quantitative differences in these immunogenic proteins of MS and normal WM, no multiple sclerosis-specific membrane antigen could be demonstrated.The hyperimmune anti-WM sera did not precipitate ³⁵S-labeled polypeptides from cells infected with herpes simplex type 1, adeno type 5, measles, mumps, rubella, respiratory syncytial, parainfluenza type 2 or cytomegaloviruses, which suggests that the MS brain WM membrane proteins do not share common antigenic determinants with the viral polypeptides.