Fifteen-day cessation of training on selected physiological and performance variables in women runners

This study examined the effects of a 15-day cessation of training on maximal oxygen consumption and selected physiological variables (maximal heart rate, cardiac output [Q], stroke volume [SV], arteriovenous oxygen difference [(a-v)O2 diff], blood plasma concentration) in 15 women middle-distance competitive runners (.VO2max: 49.8 +/- 1.1 ml.kg(-1).min(-1)). Subjects were randomly assigned to a cessation training (CT, n = 7) or maintenance training (MT, n = 8) group and tested every 5 days. Q was measured by CO2 rebreathing from which SV and (a-v)O2 diff were calculated. No significant changes were found at day 5. After 10 days there was a significant decrement in .VO2max (3.8 ml.kg(-1).min(-1)) in the CT group, being significantly lower than MT but no changes thereafter in any physiological variables. Performance (2,400 m) times did not change for MT but was significantly slower (21.5 +/- 7.1 seconds) for the CT group after 15 days, corresponding to the 7.8% decrease in .VO2max. These findings suggest that in competitive women middle-distance runners, actual performance decrements found after 15 days of CT most likely are due to declines in .VO2max.     

Nuclear grooves. Valuable diagnostic feature in May-Grünwald-Giemsa-stained fine needle aspirates of papillary carcinoma of the thyroid.

Recent reports have indicated the usefulness of nuclear grooves (clefts or notches) as an additional criterion for the diagnosis of papillary thyroid carcinoma in fine needle aspirates; most of these studies were carried out on alcohol-fixed material stained with the Papanicolaou stain or with hematoxylin and eosin, which yield good nuclear details. In the present study air-dried thyroid aspirates stained with the widely used May-Grünwald-Giemsa stain were evaluated. Nuclear grooves were observed in 88% of the May-Grünwald-Giemsa-stained aspirates from papillary thyroid carcinoma, usually in substantial numbers. A few grooved nuclei were seen in a small percentage of the other thyroid aspirates studied. These results show that nuclear grooves can also be used as a possible marker of papillary carcinoma of the thyroid in May-Grünwald-Giemsa-stained aspirates.     

Endonuclease-like activity of heme proteins

Heme proteins, metmyoglobin, methemoglobin, and metcytochrome c showed unusual affinity for double-stranded DNA. Calorimetric studies show that binding of methemoglobin to calf thymus DNA (CTDNA) is weakly endothermic, and the binding constant is 4.9+/-0.7x10(5) M(-1). The Soret absorption bands of the heme proteins remained unchanged, in the presence of excess CTDNA, but a new circular dichroic band appeared at 210 nm. Helix melting studies indicated that the protein-DNA mixture denatures at a lower temperature than the individual components. Thermograms obtained by differential scanning calorimetry of the mixture indicated two distinct transitions, which are comparable to the thermograms obtained for individual components, but there was a reduction in the excess heat capacity. Activation of heme proteins by hydrogen peroxide resulted in the formation of high valent Fe(IV) oxo intermediates, and CTDNA reacted rapidly under these conditions. The rate was first-order in DNA concentration, and this reactivity resulted in DNA strand cleavage. Upon activation with hydrogen peroxide, for example, the heme proteins converted the supercoiled pUC18 DNA into nicked circular and linear DNA. No reaction occurred in the absence of the heme protein, or hydrogen peroxide. These data clearly indicate a novel property of several heme proteins, and this is first report of the endonuclease-like activity of the heme proteins.     

Fine needle aspiration cytology in the diagnosis of sinuses and ulcers of the body surface (skin and tongue)

Both fine needle aspiration (FNA) and conventional scraping were used to obtain cytodiagnostic samples from ulcers and sinuses of the skin (18 cases) and tongue (3 cases). These included 14 cases of tuberculosis, 5 squamous-cell carcinomas and 2 cases of nonspecific infection. The FNA smears contained characteristic tuberculous granulomas or epithelioid cells in 10 of the 14 tuberculosis cases and ample diagnostic material in 4 of the 5 carcinoma cases; in contrast the scraping smears predominantly contained necrotic material on which a diagnosis was not possible. Of the 19 cases of tuberculosis and malignancy, 12 were diagnosed only by FNA, 6 were diagnosed by both methods and the FNA sample was negative while the scrape was positive in 1 case. Hence, the diagnosis was made in 18 of 19 by FNA cytology, but in only 7 of 19 cases by scraping cytology, strongly indicating the diagnostic superiority of the former in diagnosing many lesions of the body surface.     

Physiological effects of hydrogen sulfide inhalation during exercise in healthy men.

Occupational exposure to hydrogen sulfide (H2S) is prevalent in a variety of industries. H2S when inhaled 1) is oxidized into a sulfate or a thiosulfate by oxygen bound to hemoglobin and 2) suppresses aerobic metabolism by inhibiting cytochrome oxidase (c and aa3) activity in the electron transport chain. The purpose of this study was to examine the acute effects of oral inhalation of H2S on the physiological responses during graded cycle exercise performed to exhaustion in healthy male subjects. Sixteen volunteers were randomly exposed to 0 (control), 0.5, 2.0, and 5.0 ppm H2S on four separate occasions. Compared with the control values, the results indicated that the heart rate and expired ventilation were unaffected as a result of the H2S exposures during submaximal and maximal exercise. The oxygen uptake had a tendency to increase, whereas carbon dioxide output had a tendency to decrease as a result of the H2S exposures, but only the 5.0 ppm exposure resulted in a significantly higher maximum oxygen uptake. Blood lactate concentrations increased significantly during submaximal and maximal exercise as a result of the 5.0 ppm exposure. Despite these large increases in lactate concentration, the maximal power output of the subjects was not significantly altered as a result of the 5.0 ppm H2S exposure. It was concluded that healthy young male subjects could safely exercise at their maximum metabolic rates while breathing 5.0 ppm H2S without experiencing a significant reduction in their maximum physical work capacity during short-term incremental exercise.     

Abdominal Distension and Escherichia coli Peritonitis in Mice Lacking Myeloid Differentiation Factor 88

Here we describe the gross and microscopic findings of naturally occurring, β-hemolytic Escherichia coli peritonitis in B6.129-Myd88^tm1Aki male and female mice. Over approximately 5 mo, 10 homozygous mutant mice deficient in myeloid differentiation factor 88 (C57BL/6 strain; male and female) that had not been used in research protocols developed rapid-onset abdominal swelling associated with copious viscous ascites. Each mouse developed an anterior peritonitis, primarily involving the parietal peritoneum and the visceral surface of the spleen, liver, diaphragm, and stomach. Inflammation was confined to the organ surfaces, with no indication of septicemia or grossly apparent gastrointestinal perforation or other tissue compromise that would initiate peritonitis. Peritonitis was likely attributable to compromised antibacterial innate immunity; cohoused, similarly immunodeficient littermates did not develop similar clinical signs. An unusual finding in all cases was mesothelial cell hyperplasia and hypertrophy. Although the underlying innate immune deficiency accounts for much of the observed pathology, the remarkable mesothelial cell morphology and the episodic nature of the peritonitis in some littermates and not others remain unexplained.Abbreviations: MyD88, myeloid differentiation response 88; TLR, Toll-like receptorMice deficient in myeloid differentiation factor 88 (myD88) are commonly studied in immunologic research as models of various diseases, including inflammatory bowel disease and diabetes.^2,3 MyD88 is a key signal transduction molecule for most of the Toll-like receptors (TLR) and IL1 family receptors, initiating cytokine release essential for effective innate immunity.¹⁸ The loss of this adapter protein impairs production of IL1, IL6, IL18, macrophage inhibitory proteins 1 and 2, and various chemokines.^1,12,14 Knockout mutant mice are especially susceptible to gram-negative bacteria, because TLR4, which triggers signaling through MyD88, mediates responses to LPS.^7,17 These immunologic mutants are common in research animal colonies, but their development of clinical signs and lesions consistent with Escherichia coli peritonitis, which arose at different times and affected only some of the immunodeficient mice, was previously unknown.     

Muscle oxygenation during incremental arm and leg exercise in men and women

The purpose of this study was to compare the rates of muscle deoxygenation in the exercising muscles during incremental arm cranking and leg cycling exercise in healthy men and women. Fifteen men and 10 women completed arm cranking and leg cycling tests to exhaustion in separate sessions in a counterbalanced order. Cardiorespiratory measurements were monitored using an automated metabolic cart interfaced with an electrocardiogram. Tissue absorbency was recorded continuously at 760 nm and 850 nm during incremental exercise and 6 min of recovery, with a near infrared spectrometer interfaced with a computer. Muscle oxygenation was calculated from the tissue absorbency measurements at 30%, 45%, 60%, 75% and 90% of peak oxygen uptake (V˙O₂) during each exercise mode and is expressed as a percentage of the maximal range observed during exercise and recovery (%Mox). Exponential regression analysis indicated significant inverse relationships (P < 0.01) between %Mox and absolute V˙O₂ during arm cranking and leg cycling in men (multiple R = −0.96 and −0.99, respectively) and women (R =−0.94 and −0.99, respectively). No significant interaction was observed for the %Mox between the two exercise modes and between the two genders. The rate of muscle deoxygenation per litre of V˙O₂ was 31.1% and 26.4% during arm cranking and leg cycling, respectively, in men, and 26.3% and 37.4% respectively, in women. It was concluded that the rate of decline in %Mox for a given increase in V˙O₂ between 30% and 90% of the peak V˙O₂ was independent of exercise mode and gender. Accepted: 31 March 1998