The influence of training intensity, airway infections and environmental conditions on seasonal variations in bronchial responsiveness in cross-country skiers

The influence of physical training, airway infections and environmental conditions on changes in bronchial responsiveness to methacholine during a training and competitive season was studied in 19 high-performance male cross-country skiers 19-21 years old. The longitudinal changes in the methacholine concentration required for a 10% fall in FEV1 (PC10) were negatively correlated with the changes in the volume of physical activity at an intensity level above 90% of maximal heart rate. The variation in physical activity at this intensity level accounted for 54.8% of the change in PC10. No association was found, however, with regard to physical activity at lower intensity levels. Seasonal variation in PC10 was not associated with the changes in occurrence or duration of airway infections provided that the PC10 measurement was postponed for 3-6 weeks after the onset of a recent infection. Seasonal variation in PC10 seemed not to be associated with variations in ambient levels of air pollutants or aeroallergens. PC10 was lowest at the end of the coldest part of the year. In conclusion, seasonal variation in bronchial responsiveness in high-performance cross-country skiers could to a great extent be explained by changes in the volume of physical activity at a very high intensity level.

Dietary factors and colorectal polyps: a case-control study

In the case-control study we compared dietary habits among 108 patients with small (< or = 5 mm, n = 26), medium (5-9 mm, n = 48) or large (> or = 10 mm, n = 34) colorectal polyps with 35 healthy age- and gender-matched controls. A food record by weighing during 5 consecutive days was performed. The intake of fat was significantly higher among the patients, in contrast to a significantly lower intake of carbohydrate, dietary fibre and iron, compared with controls. The intake of vitamin C and calcium was shown to be lower among the patients, but this was significant only for women. There was a tendency among the patients to consume a lower-antioxidant, fibre and cereal fibre diet, and a calcium-rich and more cholesterol-rich diet with increasing size of polyps. The patients with the smallest polyps tended to consume less starch. Our results are too preliminary to draw conclusions with regard to the influence of nutritional factors on the size and growth of polyps. However, our risk factors for the presence of polyps are in agreement with previous studies. Further studies taking into account the size of the polyp are needed to corroborate our findings.

Is there a reduction in postural load when wearing progressive lenses during VDT work over a three-month period?

In an initial study, 18 VDT operators were found to have a higher muscle load in the neck/ shoulder region when using progressive lenses compared with single-vision lenses, while working on a VDT unit. For single-vision lenses, a higher flexion angle in the neck was also discovered. The present study investigates whether this higher muscle load is reduced when a progressive correction is worn for a three-month period. Adaptation in terms of reduced muscle load measured by electromyography (EMG) was not discovered. Head flexion angle was smaller when using progressive correction as compared with single-vision lenses. Some practical implications for occupational optometry are discussed.

IL-12 directly enhances in vitro murine erythropoiesis in combination with IL-4 and stem cell factor

It has been demonstrated recently that in vivo administration of murine IL-12 to mice enhances the activity of cytotoxic NK cells and lymphocyte-activated killer cells, and that it has antitumor and antimetastatic activity. However, one side effect observed in response to systemic IL-12 treatment is anemia. In the present study, we examined for the first time the ability of IL-12 to affect directly the growth of murine erythroid progenitor cells in vitro. Whereas IL-12 alone or in combination with Erythropoietin (Epo) showed no stimulatory effect on erythroid progenitors, IL-12 potently enhanced the number of erythroid burst-forming unit (BFU-E) colonies formed in response to Epo+IL-4 by 63% and Epo+stem cell factor by 80%. The stimulatory effect of IL-12 occurred in a concentration-dependent fashion, with maximum enhancing effect observed at 50 ng/ml. Furthermore, single cell experiments suggested that the stimulatory effect of IL-12 on erythroid colony formation was directly mediated. Thus, IL-12 can directly enhance murine erythropoiesis in vitro, suggesting that IL-12-induced anemia is mediated through an indirect mechanism.

IL-12 directly enhances in vitro murine erythropoiesis in combination with IL-4 and stem cell factor

It has been demonstrated recently that in vivo administration of murine IL-12 to mice enhances the activity of cytotoxic NK cells and lymphocyte-activated killer cells, and that it has antitumor and antimetastatic activity. However, one side effect observed in response to systemic IL-12 treatment is anemia. In the present study, we examined for the first time the ability of IL-12 to affect directly the growth of murine erythroid progenitor cells in vitro. Whereas IL-12 alone or in combination with Erythropoietin (Epo) showed no stimulatory effect on erythroid progenitors, IL-12 potently enhanced the number of erythroid burst-forming unit (BFU-E) colonies formed in response to Epo+IL-4 by 63% and Epo+stem cell factor by 80%. The stimulatory effect of IL-12 occurred in a concentration-dependent fashion, with maximum enhancing effect observed at 50 ng/ml. Furthermore, single cell experiments suggested that the stimulatory effect of IL-12 on erythroid colony formation was directly mediated. Thus, IL-12 can directly enhance murine erythropoiesis in vitro, suggesting that IL-12-induced anemia is mediated through an indirect mechanism.

Respiratory tract infection and bronchial responsiveness in elite athletes and sedentary control subjects

To assess the effect of physical exercise during an acute respiratory tract infection (RTI) on bronchial responsiveness, methacholine bronchial challenge tests were performed prospectively in 19 nonasthmatic male cross-country skiers and 22 healthy control subjects with minimal physical activity. Twelve skiers and 10 controls contracted RTI and were studied before and 1, 3 and 6 weeks after the onset of symptoms. The skiers were given no restrictions in their training routines during the period of illness. The geometric mean provocation concentration of methacholine causing a 10% fall in the forced expiratory volume in the first second (PC10), was lower 1 week after onset of infection than at the initial test in the skiers. From the level at 1 week, PC10 increased to levels at 3 and 6 weeks after infection. The PC10 values at 3 and 6 weeks were not significantly different from the initial test. No significant changes in PC10 occurred after infection in the control group. No significant changes in pulmonary function tests were found during the study period in either of the two groups. In conclusion, RTI was associated with a transient increase in bronchial responsiveness in athletes performing physical training during the symptomatic period of respiratory illness but not in nonactive control subjects.

A case-control study of psychological and psychosocial risk factors for shoulder and neck pain at the workplace

Risk factors associated with work-related shoulder and neck myalgia were investigated in a case-control study with pairs matched for age, gender, and physical exposure. Guided interviews with standardized and self-constructed questionnaires were performed among manual (n = 15 pairs) and office (n = 24 pairs) workers. Perceived general tension was the variable with the strongest association with shoulder and neck pain in both work groups. Otherwise, the results in the two groups were very different, indicating that different risk factors and mechanisms were associated with shoulder and neck pain in the two work groups. The study provides background information for future attempts to establish causal relationships between physical and psychosocial exposure and shoulder and neck pain, which can be more accurately investigated in a longitudinal rather than a cross-sectional experimental design.

Can a regular leg extension bench be used in testing deficits of the quadriceps muscle during rehabilitation?

Fifty-nine people, 31 healthy subjects with no previous knee injuries and 28 who had undergone an intra-articular anterior cruciate ligament reconstruction 6-12 months prior to testing took part in the study. The subjects were randomly tested bilaterally on a Cybex 6000 isokinetic testing device (ITD) and on an ordinary leg extension bench (LEB). Strength and endurance were tested with both methods. The linear relationships for paired strength and endurance differences between ITD and LEB were found to be acceptable for the operated group. The LEB alone explained 57% and 38% of the ITD outcome for strength and endurance, respectively. The agreement between observed and predicted ITD values based on the LEB measurements was found satisfactory with a positive standardized agreement index. This indicates that the LEB can be used as a helpful tool in evaluation of quadriceps muscle strength deficits.

Serum immunoglobulin G subclasses in patients with ulcerative colitis and Crohn's disease of different disease activities

BACKGROUND

Different concentrations of immunoglobulin G (IgG) subclass-producing cells in the mucosa of patients with ulcerative colitis and Crohn's disease have previously been described.

METHODS

To evaluate serum concentration of IgG subclasses as a tool for diagnosis and disease activity in chronic inflammatory bowel disease, we compared serum concentrations of IgG, IgA, IgM, and immunoglobulin subclasses IgG1, IgG2, IgG3, and IgG4 by means of the radial immunodiffusion technique in 66 patients with ulcerative colitis and in 68 patients with Crohn's disease of different clinical stages. Erythrocyte sedimentation rate, haemoglobin, and serum concentrations of albumin and orosomucoid were also determined.

RESULTS

The serum IgG1 concentration in patients with ulcerative colitis was 8.0 g/l significantly higher than in patients with Crohn's disease (6.8 g/l) (p < 0.005), whereas the serum IgG2 concentration in patients with Crohn's disease was 3.8 g/l, significantly increased compared with patients with ulcerative colitis (3.1 g/l) (p < 0.004). In patients with active ulcerative colitis the serum IgA level (2.03 g/l) was significantly lower than that in the patients with less active disease (2.74 g/l) (p < 0.03). No significant differences in serum concentrations of total IgG, IgG3, IgG4, and IgM were found between groups of patients with ulcerative colitis and Crohn's disease. The differences observed in IgG1, IgG2, and IgA concentrations, however, are small.

CONCLUSIONS

The serum concentrations of IgG, IgA, IgM, and IgG subclasses are of little value in the diagnostic procedures in individual patients and are not superior to conventional laboratory tests such as sedimentation rate and serum concentrations of orosomucoid and albumin.

The response of symptomatic neurosyphilis to high-dose intravenous penicillin G in patients with human immunodeficiency virus infection

BACKGROUND

Infection with the human immunodeficiency virus (HIV) may affect both the natural course of syphilis and the response to treatment. We examined the response to treatment with high-dose penicillin G in HIV-infected patients with symptomatic neurosyphilis.

METHODS

Neurosyphilis was defined by reactivity in serum treponemal tests for syphilis, neurologic manifestations consistent with neurosyphilis, and a positive Venereal Disease Research Laboratory (VDRL) test on cerebrospinal fluid. We identified 11 HIV-infected patients with symptomatic neurosyphilis; 5 had been treated previously for early syphilis with penicillin G benzathine. Patients were treated with 18 million to 24 million units of penicillin G per day administered intravenously for 10 days. Cerebrospinal fluid was examined approximately 6 and 24 weeks after treatment, when the polymerase chain reaction and rabbit inoculation were used to detect Treponema pallidum.

RESULTS

In four of the seven patients studied 24 weeks after treatment, the serum titers on rapid plasma reagin (RPR) testing decreased by at least two doubling dilutions, and four patients had reductions in the cerebrospinal fluid titers on VDRL testing or reverted to nonreactive results. In two patients there was no normalization or improvement in serum titers on RPR testing or cerebrospinal fluid titers on VDRL testing, cell counts, or protein concentrations. One patient relapsed with meningovascular syphilis six months after therapy. T. pallidum was detected by the polymerase chain reaction in cerebrospinal fluid from 3 of 10 patients before treatment, but in none of the 10 post-treatment specimens.

CONCLUSIONS

In patients with early syphilis who are also infected with HIV, therapy with penicillin G benzathine may fail, and neurosyphilis may develop. The regimen of high-dose penicillin recommended for neurosyphilis is not consistently effective in patients infected with HIV.

Urine profiles and kidney histology after intravenous injection of ionic and nonionic radiologic and magnetic resonance contrast media in normal rats

RATIONALE AND OBJECTIVES

Previous studies showed that both high-osmolality and low-osmolality iodinated contrast media cause temporary albuminuria and enzymuria (presence of enzymes in urine) in normal rats. Whether the same is true with ionic high-osmolality and nonionic low-osmolality magnetic resonance (MR) contrast media is unknown. We studied urine profiles and histology after intravenous injection of four types of contrast media in rats with normal kidneys.

METHODS

Urine profiles were monitored 4, 24, 48, and 72 hr after intravenous injection of saline, diatrizoate, iohexol, gadopentetate dimeglumine, and gadodiamide (4.59 mmol/kg of body weight) in normal rats. Each group included 20 male rats. After sacrifice, both kidneys were removed for examination by light microscopy (LM) and electron microscopy (EM).

RESULTS

All four contrast agents caused a temporary (< 22 hr) increase in the excretion of albumin (2-5 times) and of cytoplasmic (30-100 times) and brush border (10-100 times) renal enzymes when compared with saline. The degree of albuminuria correlated well (r = 0.90) with the osmolality of the injected media, whereas the increased level of enzymuria was unrelated to the osmolality. No major differences in the enzymuric effects of the four agents were noted. LM revealed vacuoles in all kidneys exposed to radiologic contrast media but not in kidneys exposed to MR contrast media or saline. Slight vacuolation was revealed by EM after the use of MR contrast media, and significant vacuolation was evident via EM after the use of radiologic contrast media. No difference between ionic and nonionic media within each drug group was detected by either LM or EM.

CONCLUSIONS

Transient renal effects are induced by both ionic and nonionic high-osmolality and low-osmolality radiologic and MR contrast media in normal rats. Both osmotic (e.g., albuminuria) and chemotoxic (e.g., enzymuria) mechanisms seem to be involved. From a morphologic point of view, the chemotoxic mechanisms seem to be of major importance.

Comparison of sequential and fixed-sample designs in a controlled clinical trial with laparoscopic versus conventional cholecystectomy

BACKGROUND

The aim of this study was to compare a fixed-sample and a sequential design with regard to study duration, sample size, and medical results in a real-life situation.

METHODS

A randomized study comparing laparoscopic and conventional cholecystectomy was carried out with a fixed-sample design, parallel with a sequential design. The main variable was duration of postoperative convalescence.

RESULTS

In the fixed-sample trial the necessary number of patients was calculated to be 72. The sequential trial was conclusive after inclusion of 24 patients and reduced the duration of the study from 43 to 18 weeks. Additionally, the sequential trial reached the same conclusions as the fixed-sample trial in all the observed variables except for one.

CONCLUSION

The present study indicates that sequential design should be used more frequently in clinical trials, to involve the smallest possible number of patients necessary to reach a conclusion.

Growth of colorectal polyps: recovery and evaluation of unresected polyps of less than 10 mm, 1 year after detection

BACKGROUND AND METHODS

Colonoscopic 1-year control of polyps of less than 10 mm left in situ was carried out in 103 (89%) of 116 originally examined patients.

RESULTS

Analysis showed an 85% recovery: 91% and 81% for polyps of 5-9 mm and < 5 mm, respectively. The recovery was significantly related to size and localization, whereas the growth rate was inversely correlated to the originally measured diameter. A linear relationship was demonstrated between anus-to-polyp distances 1 year apart, with a normalized agreement index of 0.70. In only 1 of 189 polyps, an increase of diameter to > 10 mm was demonstrated. The 79 new polyps in 52 (50%) of the patients were significantly smaller, more often right-sided, and related to multiplicity of polyps at the initial examination but not to growth of recovered polyps or cleansing status.

CONCLUSION

An acceptable recovery and growth rate of polyps < 10 mm seems to justify the continuation of the study for the remaining 2 years.

Alcohol use in the service industry

It is frequently alleged that hotel and restaurant personnel drink more than other groups in the service industry, although only indirect evidence has been presented to substantiate this allegation. This paper reports data from two surveys concerning alcohol use in different segments of the service industry. In the first study 84 students at three different colleges in the Stavanger region were interviewed concerning their alcohol habits using the screening instrument AUDIT (Alcohol Use Disorders Identification Test). The second survey concentrated on service employees in the Rogaland area. One hundred and five respondents answered the AUDIT questionnaire in this study. The results showed that hotel and restaurant affiliated individuals scored significantly higher on the AUDIT than the other respondents. The first survey indicated that students at the Norwegian College of Hotel Management obtained significantly higher AUDIT scores than other groups of students, whereas the second survey indicated that restaurant workers scored significantly higher than employees in other branches of the service industry. Implications of these results, as well as future research demands were indicated.

In situ measurement of colorectal polyps to compare video and fiberoptic endoscopes

The present study was performed to test the reliability of in situ measurements of colorectal polyps when comparing videoendoscopes with fiberoptic endoscopes. In 25 small rectosigmoid polyps 3-12 mm) removed endoscopically, in situ diameters were measured before polypectomy using both video- and fiberoptic endoscopes. Polaroid and videoprint pictures were taken for computerised analysis of the area of the polyps on the pictures. The results showed a good correlation between the polyp diameter measured with the videoendoscope and fiberoptic endoscope (r = 0.97), with no significant difference by parametric testing. The diameter and weight of the removed polyp also correlated well with the diameter measured in situ using videoendoscopes (r = 0.92 and 0.77, respectively) or fiberoptic endoscopes (r = 0.90 and 0.81, respectively). Furthermore, the weight of the removed polyp correlated reasonably well to the computerised area measurement, the correlation coefficient being r = 0.90 for fiberoptic endoscopes and r = 0.75 for videoendoscopes. We conclude that in situ polyp diameter measurements using videoendscopes and fiberoptic endoscopes are similarly reliable and sensitive, and both instruments can be used interchangeably in follow-up studies of polyp growth.

Prospective nonrandomized study of conventional versus laparoscopic appendectomy

With the introduction of laparoscopic appendectomy a prospective study was started. Patients with suspected appendicitis were selected for conventional appendectomy or laparoscopy according to the preference of the surgeon on call. During a 1-year period 233 patients were included, of whom 97 underwent conventional appendectomy and 136 laparoscopy. Among the patients selected to laparoscopy, laparoscopic appendectomy was carried out in 72 cases, conventional appendectomy in 32, and only diagnostic laparoscopy in the remaining 32. Removal of a normal appendix was significantly more common in the group of patients directly selected for conventional appendectomy compared to laparoscopy (p < 0.01). The duration of the operation was shorter (p < 0.05) and the postoperative hospital stay and the convalescence longer (p < 0.05) with conventional than with laparoscopic appendectomy. Peroperative problems and minor postoperative complications were more common (p < 0.01) with laparoscopic than conventional appendectomy. However, the clinical impact of these problems were limited. The difference between the procedures regarding major complications was not significant. Laparoscopic appendectomy seems to be at least as good as conventional appendectomy. However, randomized controlled trials are needed to decide which of the procedures to recommend.