Fibre type characteristics of the lumbar paraspinal muscles in normal healthy subjects and in patients with low back pain

A knowledge of the alteration in the fibre type profile of paraspinal muscle associated with low back pain is essential for the design of successful rehabilitation programmes. In attempting to compare the muscles of patients with low back pain with those of controls, few previous studies have considered factors such as gender, age, and size of the subjects, each of which can potentially confound interpretation of the results. We obtained samples of lumbar paraspinal muscle during spinal surgery from 21 patients with low back pain and, using the percutaneous biopsy technique, from 21 control volunteers matched for gender, age, and body mass. The samples were subject to routine histochemicsl typcal analysis to determine characteristics of muscle fibre type. Compared with controls, the muscle of the patients had a significantly higher proportion of type-IIB (fast-twitch glycolytic) fibres than type- I (slow oxidatve) fibres. The mean size of a given fibre type did not differ between the patients and the controls. Consequently, the relative area of the muscle iccupied by type-IIB fibres was higher and that by type-I fibres Was lower in the patients. The patients had a greater number of muscle samples with more than 1% type-IIC fibres, and abnormalities that could be described as pathological were more marked in the patients than in the controls. In conclusion, the paraspinal muscles of patients who have low back pain display a more glycolytic (faster) profile; this can be expected to render them less resistant to fatigue.     

Breast Cancer Genes

Abstract: The identification of familial breast cancer genes heralds an era of directed breast cancer treatment. Currently, two hereditary breast cancer genes have been identified, BRCA-1 and BRCA-2 . Although accounting for only approximately 5% of all breast cancers, they are being used to identify women with germ-line alterations that are at high risk of developing breast or ovarian cancer. With the identification of such genes comes a need for consideration of the ethical issues associated with testing. These genes are also being examined from a biochemical standpoint encompassing both their biological roles and biochemical pathways in which they reside. Such studies are likely to lead to novel breast cancer therapies.     

Flow cytometric analysis of induced human graafian follicles. I. Demonstration and sorting of two luteinized cell populations.

STUDY OBJECTIVE: To test the hypothesis that induced human graafian follicles consist of different steroidogenic cell types on the basis of their light scatter characteristics as determined by flow cytometry. DESIGN: Cross-sectional, observational study. SETTING: Flow cytometry laboratory. PATIENTS: Thirty-six follicular aspirates from nine consecutive patients undergoing in vitro fertilization for tubal factor infertility were evaluated. RESULTS: Two distinct luteal cell populations were recovered. Both populations were positive by Oil Red O staining, suggesting the presence of intracellular lipid. Neither population stained positively for the presence of HLe-1/CD45, an antigen present on all human leukocytes. CONCLUSIONS: Cellular heterogeneity exists within the granulosa cell compartment.     

The effects of menstrual phase and nicotine abstinence on nicotine intake and on biochemical and subjective measures in women smokers: a A preliminary report

Nicotine intake, menstrual and smoking withdrawal symptomatology, and baseline cortisol and MHPG were assessed in nine women smokers under conditions of ad lib smoking and overnight abstinence in three menstrual phases (early follicular, mid-to-late follicular, and late luteal). A trend towards higher nicotine intake p <0.100 was observed in the mid-to-late follicular phase. Although me menstrual symptomatology was not significantly elevated during the smoking abstinence condition overall, abstinence appeared to prevent the normal reduction in symptomatology during the mid-to-late follicular phase that occurred under conditions of ad lib smoking. Menstrual and withdrawal symptoms were highly correlated, and both were most pronounced during the late luteal/abstinence condition. The smoking-specific item “craving” reflected this pattern, though in attenuated form, suggesting that the observed exacerbation of withdrawal symptomatology was not simply due to generalized dysphoria, as queried in both instruments. MHPG was significantly elevated in the late luteal phase, whereas cortisol was significantly higher during ad lib smoking than during abstinence and tended to be highest in the mid-to-late follicular phase. Further investigation will be needed to determine the functional significance of these findings for understanding and treating smoking in women.     

Sudden infant death syndrome and small airway occlusion: facts and a hypothesis

Respiratory failure is almost certainly the cause of death in the majority of cases of sudden infant death syndrome (SIDS), but the mechanisms leading to it have not been elucidated. SIDS shares many environmental and socioeconomic risk factors with severe forms of bronchiolitis, and the age distribution of incident cases is similar. Present knowledge of lung and airway development during infancy, determinants of peripheral airway patency, changes in lung surface activity in infants with SIDS, and fluid film dynamics in small airways are reviewed. It is hypothesized that many cases of SIDS may be due to a final episode of progressive peripheral bronchial occlusion in infants with preceding critically diminished conductance of the smaller airways.