Age at menarche and cancer risk at adulthood

Aim: The aim was to evaluate the association between age at menarche and cancer using a nationally representative sample of Brazilian women.

Methods: Data from the Brazilian Health Survey (PNS), a nationally representative survey conducted in 2013 (n?=?33,715 women;?≥18 years), were used. Information on cancer diagnosis, age at menarche and other co-variables (chronological age, educational status, skin colour, menopause, leisure-time physical activity and tobacco smoking) were collected via interview. Logistic regression models were used for aetiological analyses.

Results: The prevalence of cancer diagnosis was greater among women with early age at menarche [2.6% (2.0–3.5%)] compared to on-time [1.6% (1.4–1.9%)] and late women [2.0% (1.1–3.4%)]. The onset of menarche ≤11 years was significantly associated with cancer risk, regardless of co-variables [OR =2.45 (1.34–4.48)], compared to the late group.

Conclusion: Early age at menarche was associated with cancer risk in adulthood, regardless of race, educational status, chronological age, obesity, menopause onset, tobacco smoking or physical activity.     

Primary immunodeficiency studies at University of Alabama at Birmingham

Over the past two decades the genetic bases for virtually all the well-characterized primary immunodeficiency syndromes have been identified. The investigation of rare, poorly differentiated immunodeficiencies is being hampered by a preoccupation of funding agencies with hypothesis-driven proposals that apply poorly in the case of individual patients. Recent studies at our institution in collaboration with groups at NIH have resulted in the identification of two separate kindreds bearing unique mutations in molecules affecting immune function and a chromosomal linkage in a third family. Thus, a potential solution to the funding problem for studies in primary immunodeficiency could lie in the centralization of investigative expertise and support, perhaps within the walls of the National Institutes of Health, as has been done with great success in Europe.     

Reference dosimetry at the neutron capture therapy facility at Studsvik

The purpose of this publication was to present and evaluate the methods for reference dosimetry in the epithermal neutron beam at the neutron capture therapy facility at Studsvik. Measurements were performed in a PMMA phantom and in air using ionization chambers and activation probes in order to calibrate the epithermal neutron beam. Appropriate beam-dependant calibration factors were determined using Monte Carlo methods for the detectors used in the present publication. Using the presented methodology, the photon, neutron and total absorbed dose to PMMA was determined with an estimated uncertainty of +/- 5.0%, +/- 25%, and +/- 5.5% (2 SD), respectively. The uncertainty of the determination of the photon absorbed dose was comparable to the case in conventional radiotherapy, while the uncertainty of the neutron absorbed dose is much higher using the present methods. The thermal neutron group fluence, i.e., the neutron fluence in the energy interval 0-0.414 eV, was determined with an estimated uncertainty of +/- 2.8% (2 SD), which is acceptable for dosimetry in epithermal neutron beams.     

Probability of transmitter release at neocortical synapses at different temperatures

The probability of transmitter release at synaptic terminals is one of the key characteristics of communication between nerve cells because it determines both the strength and dynamic properties of synaptic connections. To assess the distribution of the release probabilities at excitatory synapses on supragranular pyramidal cells in rat visual cortex, we have used the MK-801, a blocker of the open N-methyl-d-aspartate (NMDA) receptor-gated channels. With this method, the release probability can be calculated from the time course of the blockade of NMDA-receptor mediated postsynaptic currents in the presence of MK-801. At temperatures >32 degrees C, the distribution of release probabilities covered the range from 0.05 to 0.43 [mean: 0.171 +/- 0.012 (SE), n = 65], being skewed toward low values. When estimated at room temperature (22-25 degrees C), the release probabilities were significantly lower (mean: 0.123 +/- 0.009, n = 54), and almost the whole distribution was restricted to values <0.2. Furthermore, warming from room temperature to >32 degrees C led to a pronounced overshooting increase of the release probability. Taken together, the results of the present study show that release probabilities at synapses formed onto layer 2/3 pyramidal cells in the visual cortex vary significantly, but values >0.3 are rare and the results obtained either at room or variable temperature differ significantly from those made under conditions of constant temperature in the physiological range.     

The Prehistoric hand pictures at Gargas: attempts at simulation

A number of experimental methods of reconstructing prehistoric hand images like those in the cave of Gargas, France, are described and assessed. The results of experiments using these methods are evaluated from the point of view of the bearing they have on our knowledge about the creation of the original pictures in the cave.     

Athletes at altitude

1. Six international middle-distance runners were investigated during 4 weeks in England and during a similar period in Mexico City (2270 m (7450 ft.))2. In 3-mile (4828 m) time trials at 2270 m the increase in time taken by four subjects compared with sea level was 8.5% on the 4th day and 5.7% on the 29th day. There was thus a gain of 2.8% or 20 sec in time associated with acclimatization.3. In 1-mile (1609 m) time trials the times were increased by 3.6% in the first week at altitude and by 1.5% in the 4th week. The improvement amounted to 2.1%, or 4.9 sec.4. In 5 min maximum exercise on the ergometer maximum O(2) intake for six subjects at altitude was reduced by 14.6% on the 2nd day and 9.5% on the 27th. Only one subject showed no change in maximum oxygen intake (V(O2, max)) with time spent at altitude.5. Although V(O2, max) was persistently reduced at altitude work rates finally exceeded sea-level values, owing to increased over-all efficiency.6. Forty-minute recovery O(2) intakes after 5 min maximum exercise averaged 17.35 l. at sea level and 17.53 l. at altitude. Mean values from 40th to 50th min were within +/- 7% of pre-exercise values.7. Serial tests at increasing loads yielded a straight-line relation between O(2) intake and work rate over a wide range of work rates at sea level and at altitude. Heart rate and ventilation for given work intensity were maximal in the first 2-10 days at altitude and thereafter declined.8. Capillary HbO(2) saturation fell from 93% at rest to 87% in maximum exercise. The corresponding alveolar gas tensions were P(A, O2) 89 mm Hg, P(A, CO2) 24 mm Hg. About half the total unsaturation in maximum exercise was explained by the Bohr effect.9. In six of eight pairs of determinations V(O2, max) measured on the ergometer was within +/- 0.15 l./min of V(O2, max) measured on the running track. Nevertheless, it was not possible to predict running performance from ergometer measurements.