In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
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Question: Context: The present study was designed to investigate whether H2S can protect testicular germ cells against heat exposure induced injury and the underlying mechanisms.', 'It was found that all three H2S generating enzymes, cystathionine β-synthase (CBS), cystathionine γ-lysase (CSE), and 3-mercaptopyruvate sulfurtransferase (3 MST), were expressed in mouse testicular tissue. Three episodes of heat exposure (42 °C, 30 min/day, 3 days) significantly decreased endogenous H2S production and down-regulated the expression of CBS and CSE in testes. In primary cultured testicular germ cells, exogenous application of NaHS (an H2S donor) attenuated heat stress (42 °C, 30 min) induced cell death and apoptosis. This was mediated by the inhibitory effects of H2S on cytochrome C release and the ratio of the Bax/Bcl-2. NaHS also improved mitochondrial function by decreasing oxygen consumption and increasing ATP production. NaHS treatment also stimulated SOD activity and reduced ROS production.\Question: Does hydrogen sulfide protect testicular germ cells against heat-induced injury?

Answer: Our results revealed both physiological and pharmacological roles of H2S in testicular germ cells. Exogenous application of H2S may protect germ cells by preservation of mitochondrial function and stimulation of anti-oxidant activity.


Question: Context: The quantity of the silver-stained nucleolar proteins (AgNOR proteins) measured in situ in cytohistologic preparations is related to the rapidity of cell proliferation. The term "AgNOR proteins" comprises several proteins. The relationship between the individual AgNOR protein amount and cell proliferating activity is not yet known. We studied the quantitative distribution of the individual AgNOR proteins, with specific attention to the two major AgNOR proteins, nucleolin and protein B23, in seven human cancer cell lines characterized by different cell doubling times.', 'The doubling time of cancer cells was measured by counting the asynchronously growing cells at regular time intervals. The AgNOR proteins were quantified in situ, after a specific one-step staining procedure, by computerized image analysis. For the quantitative evaluation of nucleolin and protein B23, two methods were followed. Nuclear proteins after separation by SDS-PAGE were transferred onto nitrocellulose membranes and were either: 1) stained by the silver staining procedure for AgNOR proteins or 2) treated with anti-nucleolin and anti-protein B23 mAb followed by reaction with secondary Ab linked to peroxidase and revealed by chemiluminescence and autoradiography. In both cases, measurement of individual AgNOR protein and nucleolin and protein B23 amount was carried out using computerized densitometric analysis.', 'Integrated density values of the silver-stained bands at 105 kDa (nucleolin) and 38 to 39 kDa (protein B23) represented, in all cell lines, more than 60% of the total silver-stained band value. A relationship was found between the densitometric values of silver-stained nucleolin and protein B23 and rapidity of cell proliferation (r = 0.85 and r = 0.86, respectively, p < 0.05). The values of nucleolin and protein B23 obtained using the Western blots were strictly related to the rapidity of cell proliferation (r = 0.93 and 0.96, respectively, p < 0.001). Finally, a good correlation was observed between the mean AgNOR protein area value, as defined in cytologic preparations in situ, and nucleolin and protein B23 amounts as evaluated in silver-stained nitrocellulose membranes (r = 0.92 and r = 0.90, respectively, p < 0.01) and in Western blots (r = 0.95 and r = 0.94, respectively, p < 0.001).\Question: Is the quantity of nucleolar proteins nucleolin and protein B23 related to cell doubling time in human cancer cells?

Answer: These data indicate that the quantitative changes of AgNOR proteins observed in cytohistologic preparations in situ mainly reflect the quantitative changes of nucleolin and protein B23 and demonstrate that nucleolin and protein B23 amounts are inversely related to cell doubling time in human cancer cells.


Question: Context: Walking is usually undertaken at a speed that coincides with the lowest metabolic cost. Aging however, alters the speed-cost relationship, as preferred walking speeds decrease and energy costs increase. It is unclear to what extent this relationship is affected when older women undertake walking as an exercise modality. The aim of this study was to compare the energetic cost of walking at a self-selected exercise pace for a 30 minute period in older and younger women.', "The energetic cost of walking was assessed using the energy equivalent of oxygen consumption measured in 18 young (age 25 to 49 years) and 20 older (age 50 to 79 years) women who were asked to walk at their 'normal' exercise pace on a motorized treadmill for 30 minutes duration.", 'The mass-specific net cost of walking (Cw) was 15% higher and self-selected walking speed was 23% lower in the older women than in the younger group. When speed was held constant, the Cw was 0.30 (J.kg-1.m-1) higher in the older women.\Question: Is walking speed at self-selected exercise pace lower but energy cost higher in older versus younger women?

Answer:
Preferred exercise pace incurs a higher metabolic cost in older women and needs be taken into consideration when recommending walking as an exercise modality.