Polymyositis with cytochrome C oxidase negative fibers—a pathological and clinical challenge

Polymyositis (PM) with cytochrome C oxidase negative fibers also referred to as PM with mitochondrial pathology (PM-Mito) is characterized by the symptoms of inclusion body myositis (IBM) and by the myopathological findings of PM except for an increase of muscle fibers with insufficient mitochondrial cytochrome C oxidase activity. Few PM-Mito cases are published; mitochondrial ultrastructure has not been studied in these patients. We report 2 PM-Mito patients with later onset than usually seen in IBM and poor responsiveness to glucocorticoids. Electron microscopy of muscle fibers showed irregular mitochondrial ultrastructure. Sjögren syndrome related antinuclear antibodies (Anti-Ro and Anti-La) were found in one of the two patients but the typical clinical symptoms of Sjögren syndrome such as xerostomia and keratoconjunctivitis were absent in this patient. Taken together, our observations, viewed in conjunction with the current literature, suggest that PM-Mito is an underdiagnosed disease with a multifactorial pathogenesis that should be elucidated in further studies. We want to encourage clinicians and pathologists to consider the possibility of PM-Mito in patients with atypical PM or sIBM.     

Effects of 84‐days of bedrest and resistance training on single muscle fibre myosin heavy chain distribution in human vastus lateralis and soleus muscles

Aim: This investigation determined the effects of 84 days of bedrest on the composition of myosin heavy chain (MHC) in single skeletal muscle fibres with and without a resistance‐training countermeasure programme. Methods: Muscle biopsies were obtained from the m. vastus lateralis (VL) and m. soleus (SOL) before and after 84 days of bedrest. While control (BR) subjects (VL n = 9; SOL n = 3) refrained from exercise, BRE subjects (VL n = 8; SOL n = 3) performed knee extensor and plantar flexor resistance exercise every third day. Approximately 110 fibres per sample were analysed for MHC composition using SDS‐PAGE. Results: BR–VL had 16 and 14% decreases (P < 0.05) in MHC I and IIa fibres, respectively. There were 10% increases (P < 0.05) in MHC I/IIa, IIa/IIx, I/IIa/IIx, and a ～30% increase (P < 0.05) in total hybrid fibres. BRE‐VL showed a 15% reduction (P < 0.05) in MHC I fibres, no change in MHC IIa fibres, and a 13% increase (P < 0.05) in total hybrids. BR–SOL had a 19% decrease (P < 0.05) in MHC I fibres with a 22% increase in total hybrids. BRE–SOL showed no change in MHC composition across all fibre types. Conclusion: These data suggest that the exercise countermeasures programme prevented MHC shifts in the SOL and mitigated MHC shifts in the VL. Furthermore, in the VL it appears that the resistance training programme employed in this investigation during bedrest, emphasized the use of MHC IIa phenotype muscle fibres.     

Outcome of major cardiac injuries at a Canadian trauma center

Background  

Canadian trauma units have relatively little experience with major cardiac trauma (disruption of a cardiac chamber) so injury outcome may not be comparable to that reported from other countries. We compared our outcomes to those of other centers.     

Role of polymorphic human cytochrome P450 enzymes in estrone oxidation.

Estrogen and its metabolites are believed to play important roles in breast cancer. The influence of genetic polymorphisms in the enzymes responsible for formation and disposition of estrogen on breast cancer risk may shed light on the importance of estrogen metabolites in this disease. However, for such studies to be valid, it is important to correctly identify the enzymes involved in estrogen bioactivation. Therefore, we assessed the human cytochrome P450-dependent oxidation of estrone using substrate concentrations that more closely approximate the maximum expected concentrations in breast tissue. The in vitro metabolism of estrone by recombinant human cytochrome P450 enzymes and human liver microsomes was studied. The formation of estrone metabolites (2-hydroxyestrone, 4-hydroxyestrone, and 16alpha-hydroxyestrone) was monitored by high-performance liquid chromatography. 2-Hydroxyestrone formation was catalyzed predominantly by CYP1A2, CYP1A1, and CYP1B1 enzymes; 4-hydroxyestrone formation was catalyzed predominantly by CYP1B1, CYP1A2, and CYP1A1 enzymes; and 16alpha-hydroxyestrone formation was catalyzed predominantly by CYP2C19, CYP1A1, and CYP3A5. This study confirms the important role of members of the CYP1 family in the 2-hydroxylation and 4-hydroxylation of estrone, but the enzymes identified as responsible for the 16alpha-hydroxylation of estrone are different from those previously identified. The relative importance of these enzymes in vivo would depend on the specific tissue expression of the enzymes. These enzymes are all known to be genetically variant in the human population, and additional studies to assess the role CYP1A2, CYP2C19, and CYP3A5 in breast cancer risk are indicated.     

Does the amniotic fluid protein absorption contribute significantly to the fetal weight?

Objective : This study was carried out to evaluate the significance of amniotic fluid protein ingestion and absorption on fetal growth.
Methodology : Neonates with small bowel atresia during a 30 year period were studied retrospectively.
Results : There were 56 patients enlisted, 17 with duodenal atresia, 18 with jejunal atresia and 21 with ileal atresia. The percentage of mothers with polyhydramnios and the percentage of premature babies decreases as the intestinal atresia becomes more distal. The mean gestational age and the mean birthweight increase as the intestinal atresia becomes more distal. On the other hand, the percentage of the neonates with birthweight below the 50th and the 10th percentiles do not differ significantly as the intestinal atresia becomes more distal.
Conclusions : It appears that the variation of birthweights in babies with different levels of small bowel atresia may be due to the difference in gestation caused by polyhydramnios. The effect of amniotic fluid protein absorption on fetal bodyweight could not be demonstrated clinically in this study.     

Unilateral haemorrhagic parenchymal lesions in the preterm infant: shape, site and prognosis

Rademaker KJ, Groenendaal F, Jansen GH, Eken P, de Vries LS. Unilateral haemorrhagic parenchymal lesions in the preterm infant: shape, site and prognosis. Acta Pædiatr 1994;83:602–8. Stockholm. ISSN 0803–5253 In a prospective cranial ultrasound study of 544 infants with a gestational age of 32 weeks or less, 20 (3.6%) infants were diagnosed as having a unilateral parenchymal lesion (PL). Based on the shape of the PL and the evolution on ultrasound, the infants were divided into three groups: group I consisted of 11 infants, in whom the PL was triangular/fan-shaped and separate from the ventricle. The PL evolved into small cystic lesions; group II comprised 3 infants who had a PL with a similar shape, but partially communicating with the ventricle; group III consisted of 6 infants who had a globular-shaped lesion in communication with the ventricle. In groups II and III, the PL evolved into one porcncephalic cyst. The PL was considered to be due to venous infarction in all cases with intraventricular haemorrhage preceding the PL in 7 cases. Sixteen infants survived. A postmortem was performed in 2 of the 4 infants who died, confirming the diagnosis of venous infarction. Neurologicdl sequelae were present in only 2 cases in the first group, while all 6 survivors of the other two groups developed mild to severe hemiplegia. Long-term follow-up was not always available and 4 of the 18 survivors were still less than 18 months when last seen. In 9 of the 11 infants in group I, the PL was localized in the frontoparietal region, while in 8 of the 9 infants in group II or III, the PL was beyond the trigone in the occipital region. The outcome of the unilateral PL is not always unfavourable. It was evident that not only the shape of the lesion and whether or not there was communication with the lateral ventricle, but also the site of the lesion (whether or not it extended into the occipital periventricular white matter) appeared to be important with regard to neurodevelopmental outcome.     

Semi-automatic blood lactate assay: experiences from an exercise laboratory

A semi-automatic system based on flow injection analysis (FIA) for the transportation of small sample aliquots has been combined with fluorometric, enzymatic methods for blood lactate determination and has been described earlier. In the present study duplicate blood samples were obtained from exercising subjects to enable a comparison of lactate concentrations between neutralized and non-neutralized samples. Duplicate samples were also obtained to enable FIA lactate values to be compared to those obtained with a manual enzymatic method, and with a colorimetric method. No significant change was observed if the sample was not neutralized, enabling a more rapid sample turnover. The FIA method was reliable, with a coefficient of variation of 4.9% between duplicate blood samples. FIA lactate values were valid when compared to two other manual assays. FIA has been shown to be a rapid (60 samples x h-1) means of accurately determining blood lactate concentrations with 25 microliter blood samples and is of particular relevance to the exercise laboratory.     

Depression levels in chronic orofacial pain patients: a pilot study

The assessment of depressive behaviour in chronic pain patients is especially important, because depression is commonly associated with chronic pain. The aim of this pilot study was to compare depression levels between patients with head and neck cancer pain and temporomandibular disorders (TMD), and to determine whether there is an association between depression levels and chronic pain severity. This study was an observational and sectional study and the sample consisted of 40 patients, uniformly divided into those with chronic orofacial pain related to cancer and those with painful TMD classified with research diagnostic criteria for temporomandibular disorders (RDC/TMD) axis I. Depression levels, pain intensity and severity were assessed with RDC/TMD axis II. The study demonstrated statistically significant differences in depression levels present in the head and neck cancer pain group and the painful TMD group, with the occurrence of a moderate statistically significant correlation between depression levels and chronic pain severity.