Blood tests as biomarkers for the diagnosis and prognosis of sudden sensorineural hearing loss in adults: a systematic review.

OBJECTIVE: Sudden sensorineural hearing loss is considered idiopathic in up to 90 per cent of cases. This study explored the role of blood tests as biomarkers for the diagnosis and prognosis of sudden sensorineural hearing loss. METHOD: Two researchers filtered 34 papers into the final review. This review was pre-registered on the Prospero database and conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. RESULTS: Raised inflammatory markers are almost universal in sudden sensorineural hearing loss, suggesting an inflammatory or autoimmune process. The most useful biomarkers are neutrophil-lymphocyte ratio, platelet-lymphocyte ratio and fibrinogen level. Focused investigations should be deployed on a case-by-case basis to identify underlying metabolic, infective and autoimmune conditions. CONCLUSION: A full blood count and coagulation screen (fibrinogen) is recommended in all cases of sudden sensorineural hearing loss. These are inexpensive, accessible and offer as much diagnostic and prognostic information as any other biomarker. There is emerging evidence regarding specific biomarkers for sudden sensorineural hearing loss prognosis, with heat shock protein-70, anti-endothelial cell antibody and prestin demonstrating potential; investigation of their validity through prospective, controlled research is recommended.

Antiperspirant use as a risk factor for breast cancer in Iraq.

Some internet communications have addressed the link between antiperspirant use and breast cancer. We studied the possible association between the use of antiperspirants and some other factors with the development of breast cancer in Al-Kadhmia teaching hospital. Thus, 54 cases of breast cancer and 50 controls were interviewed. We found 82.0% of the controls used antiperspirants compared with 51.8% of cases (P< 0.05). The use of antiperspirants had no association with the risk of breast cancer, while family history and oral contraceptives use were found to be associated.

Antiperspirant use as a risk factor for breast cancer in Iraq

Some internet communications have addressed the link between antiperspirant use and breast cancer. We studied the possible association between the use of antiperspirants and some other factors with the development of breast cancer in Al-Kadhmia teaching hospital. Thus, 54 cases of breast cancer and 50 controls were interviewed. We found 82.0% of the controls used antiperspirants compared with 51.8% of cases [P< 0.05]. The use of antiperspirants had no association with the risk of breast cancer, while family history and oral contraceptives use were found to be associated

Critical oxygen tension in rat brain: a combined (31)P-NMR and EPR oximetry study.

The relationship between cerebral interstitial oxygen tension (Pt(O(2))) and cellular energetics was investigated in mechanically ventilated, anesthetized rats during progressive acute hypoxia to determine whether there is a "critical" brain Pt(O(2)) for maintaining steady-state aerobic metabolism. Cerebral Pt(O(2)), measured by electron paramagnetic resonance oximetry, decreased proportionately to inspired oxygen fraction. (31)P-nuclear magnetic resonance measurements revealed no changes in P(i), phosphocreatine (PCr)/P(i) ratio, or intracellular pH when arterial blood oxygen tension (Pa(O(2))) was reduced from 145.1 +/- 11.7 to 56.5 +/- 4.4 mmHg (means +/- SE). Intracellular acidosis, a sharp rise in P(i), and a decline in the PCr/P(i) ratio developed when Pa(O(2)) was reduced further to 40.7 +/- 2.3 mmHg. The corresponding Pt(O(2)) values were 15.1 +/- 1.8, 8.8 +/- 0.4, and 6.8 +/- 0.3 mmHg. We conclude that over a range of decreasing oxygen tensions, cerebral oxidative metabolism is not sensitive to oxygen concentration. Oxygen becomes a regulatory substrate, however, when Pt(O(2)) is decreased to a critical level.

In vivo gradient echo microimaging of rodent spinal cord at 7 T.

An optimization scheme was developed for gradient echo imaging using a half-birdcage RF coil at 7 T to obtain maximal contrast between gray and white matter in the spinal cord of rodents. This optimization was combined with microimaging techniques to obtain in vivo pixel sizes of 78 x 78 x 700 microm. These techniques can be implemented in an in vivo study to investigate the myelin structure within the white matter of the rodent spinal cord.

Intracellular [Ca2+] staircase in the isovolumic pressure--frequency relationship of Langendorff-perfused rat heart.

Fluorescence and 31P magnetic resonance spectroscopy have been used to monitor simultaneously, the [Ca2+]i staircase and high energy phosphate metabolism in isolated Langendorff-perfused rat heart paced at 2, 4 and 6 Hz. In order to investigate further the relationship between high energy phosphate metabolism and the calcium staircase we perturbed the intracellular phosphocreatine (PCr)/creatine concentration with dietary beta-guanidinopropionic acid (beta-GPA). We have observed that: (a) At 2 Hz stimulation, the ventricular -Ca2+-i-dependent fluorescence decay is biexponential and continues to decay throughout the interstimulus interval; (b) at 4 Hz and 6 Hz, the [Ca2+]i decay is monoexponential; (c) end-diastolic [Ca2+]i is elevated at higher stimulation frequencies; (d) net [Ca2+]i flux per cycle is reduced at higher stimulation frequencies and is therefore correlated inversely with stimulation frequency and end-diastolic [Ca2+]i; (e) "heart rate * [Ca2+]i flux product" which is a measure of the work done in cycling calcium, is directly proportional to stimulation frequency; (f) the hysteresis between peak ventricular isovolumic pressure and peak fluorescence is decreased at higher stimulation frequencies; (g) no correlation was detected between the PCr/ATP ratio and stimulation frequency; (h) despite a 60% decrease in the myocardial PCr/ATP ratio after beta-GPA feeding, rat heart is able to maintain the end-diastolic [Ca2+]i-dependent fluorescence, and therefore the [Ca2+]i staircase relationship, similar to that of normal rat heart. In conclusion, using a physiological stimulation range and substrate supply we have observed a negative staircase of both [Ca2+]i and isovolumic pressure in whole heart which is not hypoxic. We propose that the inability of the sarcoplasmic reticulum to sequester sufficient cytosolic calcium at high stimulation frequencies leads to an elevation in end-diastolic [Ca2+]i, decreased net calcium flux per cycle resulting in a negative [Ca2+]i staircase and thus a negative isovolumic pressure-frequency relationship. We did not detect any correlation between steady-state high energy phosphate metabolism and stimulation frequency.

Intracellular Ca2+ transients in isolated perfused rat heart: measurement using the fluorescent indicator Fura-2/AM.

We have investigated the nature of Fura-2/AM loading into isolated perfused rat heart and the temporal and kinetic relationship between left ventricular [Ca2+]i dependent fluorescence and isovolumic pressure. The contribution of hydrolysed mitochondrial matrix Fura-2 fluorescence to that measured from the surface of the heart was estimated to be 43.9 +/- 5.5% by the addition of 100 microM Mn2+ to the perfusate. Maximum endothelial Fura-2 fluorescence ratio, estimated by the addition of 3 microM bradykinin to the perfusate, was found to constitute 33.6 +/- 2.7% of the maximum myocardial Fura-2 fluorescence ratio. Approximately 11.2% of the 340 nm surface fluorescence was insensitive to 20 mM Mn2+ in the presence of ionomycin (3 microM) and therefore indicates the degree of partial hydrolysis of Fura-2/AM. Thus, depending on the contribution of endothelial Fura-2 fluorescence at a physiological endothelial calcium concentration, cytosolic fluorescence may comprise between 11-45% of the total cellular fluorescence at 340 nm. Net tissue interference of the Fura-2 fluorescence ratio by NADH emission and myoglobin absorption remained unaltered, providing the oxygenation state of the tissue was unaltered throughout the experiment. The [Ca2+]i dependent fluorescence decay from peak systole was best fitted to a biexponential decay with fast and slow rate constants of 18.08 +/- 1.97 s-1 and 0.23 +/- 0.02 s-1, respectively. In addition, a phase shift was observed between temporal and kinetic measurements of the left ventricular isovolumic pressure and calcium dependent fluorescence traces during a contraction-relaxation cycle. We conclude that despite imperfect Fura-2/AM loading, the temporal and kinetic characteristics of intracellular [Ca2+] transients in normal isolated perfused rat heart are similar to those reported in more controlled preparations such as isolated myocytes and cardiac trabeculae.