There is differential loss of pyramidal cells from the human hippocampus with survival after blunt head injury

The experimental literature has shown that neurons within sub-fields of the hippocampus possess differential sensitivities to cell loss after different types of insult to the brain. In humans, after blunt head injury, differential neuronal responses between sub-fields of the hippocampus up to 72 hours after injury have been documented. But, in only a small part of the literature have data for alterations in real numbers of neurons been provided. In this study the hypothesis was tested that, after severe blunt head injury in humans, the total number of neurons within a defined volume of brain tissue differed between different sub-fields of the hippocampus and between groups of patients with differing post-traumatic survivals. Stereological methods were used to measure total cross-sectional area of sub-fields of the hippocampus taken at the level of the lateral geniculate nucleus and count numbers of neurons within each of the CA1, CA2, CA3, and CA4 sub-fields of the hippocampus in patients. The patients used in this study were categorized as follows: Group 1 (early) had survived for 1 week or less; Group 2 (late) survived 6 months or longer after fatal severe head injury; and Group 3 (controls) consisted of age-matched patients that had no history of head injury or disease prior to death. There was a significant loss in cross-sectional area in sub-fields CA3 and CA4 at 1 week or less after injury and in sub-field CA1 at 6 months and greater survival. There was no change in CA2. There was loss of neurons from within a predefined volume of brain tissue in sub-fields CA1, CA3, and CA4 one week or less after injury. But there was no loss in CA2. There was continued loss of neurons from sub-fields CA1 and CA4 between 1 week and 6 months and greater survival, but there was no loss of neurons in sub-fields CA2 and CA3 within the same period. These novel data show that after human severe head injury there is first an acute loss (1 week or less survival) of pyramidal neurons in all hippocampal sub-fields except CA2. Second, there is an ongoing loss of neurons in sub-field CA1 and, most notably, in sub-field CA4, in patients surviving for more than 6 months. However, in neither group of patients is there loss of neurons from sub-field CA2.     

Chromosomal aberrations in benign and malignant Bilharzia-associated bladder lesions analyzed by comparative genomic hybridization

Background

Bilharzia-associated bladder cancer (BAC) is a major health problem in countries where urinary schistosomiasis is endemic. Characterization of the genetic alterations in this cancer might enhance our understanding of the pathogenic mechanisms of the disease but, in contrast to nonbilharzia bladder cancer, BAC has rarely been the object of such scrutiny. In the present study, we aimed to characterize chromosomal imbalances in benign and malignant post-bilharzial lesions, and to determine whether their unique etiology yields a distinct cytogenetic profile as compared to chemically induced bladder tumors.

Methods

DNAs from 20 archival paraffin-embedded post-bilharzial bladder lesions (6 benign and 14 malignant) obtained from Sudanese patients (12 males and 8 females) with a history of urinary bilharziasis were investigated for chromosomal imbalances using comparative genomic hybridization (CGH). Subsequent FISH analysis with pericentromeric probes was performed on paraffin sections of the same cases to confirm the CGH results.

Results

Seven of the 20 lesions (6 carcinomas and one granuloma) showed chromosomal imbalances varying from 1 to 6 changes. The most common chromosomal imbalances detected were losses of 1p21-31, 8p21-pter, and 9p and gain of 19p material, seen in three cases each, including the benign lesion.

Conclusion

Most of the detected imbalances have been repeatedly reported in non-bilharzial bladder carcinomas, suggesting that the cytogenetic profiles of chemical- and bilharzia-induced carcinomas are largely similar. However, loss of 9p seems to be more ubiquitous in BAC than in bladder cancer in industrialized countries.

     

Cadence, power, and muscle activation in cycle ergometry

PURPOSE: Based on the resistance-rpm relationship for cycling, which is not unlike the force-velocity relationship of muscle, it is hypothesized that the cadence which requires the minimal muscle activation will be progressively higher as power output increases. METHODS: To test this hypothesis, subjects were instrumented with surface electrodes placed over seven muscles that were considered to be important during cycling. Measurements were made while subjects cycled at 100, 200, 300, and 400 W at each cadence: 50, 60, 80, 100, and 120 rpm. These power outputs represented effort which was up to 32% of peak power output for these subjects. RESULTS: When all seven muscles were averaged together, there was a proportional increase in EMG amplitude each cadence as power increased. A second-order polynomial equation fit the EMG:cadence results very well (r2 = 0.87- 0.996) for each power output. Optimal cadence (cadence with lowest amplitude of EMG for a given power output) increased with increases in power output: 57 +/- 3.1, 70 +/- 3.7, 86 +/- 7.6, and 99 +/- 4.0 rpm for 100, 200, 300, and 400 W, respectively. CONCLUSION: The results confirm that the level of muscle activation varies with cadence at a given power output. The minimum EMG amplitude occurs at a progressively higher cadence as power output increases. These results have implications for the sense of effort and preferential use of higher cadences as power output is increased.     

Lactate and Pyruvate Levels in the Testicular Vein of Subfertile Males with Varicocele as a Test for the Theory of Underlying Hypoxia

Lactat- und Pyruvat-Werte in der Vena testicularis von subfertilen Männern als Test für die Theorie der vorhandenen Hypoxie
Um die These von der testikulären Hypoxie bei subfertilen Männern mit Varikocele zu überprüfen wurden die Blutwerte von Lactat und Pyruvat aus der Vena testicularis mit denen einer Kontrollgruppe verglichen. Statistisch ergab sich ein niedrigerer Mittelwert für Lactat und Pyruvat bei den Varikocele-Patienten. Daraus wird die Schlußfolgerung gezogen, daß bei Varikocele keine Akkumulation von Milchsäure erfolgt und daß damit eine Hypoxie ausgeschlossen werden kann. Als die Mittelwerte der Konzentrationen für Lactat und Pyruvat in der Vena testicularis miteinander korreliert wurden, deutete sich an, daß bei Vorhandensein einer Varikocele eine gestörte Glykolyse besteht, die dem Stadium der Pyruvatbildung vorhergeht.