Spectroscopic observations on human pigmentation.

BACKGROUND: The main chromophores of human skin are melanins and hemoglobins along with carotenoids, bilirubin, and other compounds. In an effort to study the spectral signatures of skin melanin, we measured absorption spectra in a variety of situations, including a method to show early signs of re-pigmentation in vitiligo. METHODS: To measure skin in vivo, the essential component was a "Bifurcated Optical Fiber" with one end connected to the light source and the second end connected to the spectrometer while the common end was placed on the skin. RESULTS: In a typical in situ "melanin in skin" spectrum, the absorbance values first rise gradually, from 750 to 600 nm, then rise moderately from 600 to 450 nm, and rise sharply from 450 nm to a broad peak at 335 nm, below which it gradually rolls down to much lower values. CONCLUSION: We successfully studied melanin spectroscopically in subjects with vitiligo lesions, obtaining the differential spectra. Higher melanin levels can be shown by steeper negative slopes of a straight line fitted between 620 and 720 nm. Also, absorption peak at 335 nm showed the presence of melanin.

Fasting Versus Non-Fasting Total Testosterone Levels in Women During the Childbearing Period.

Background Total testosterone in men should be measured in the fasting state early in the morning with at least two samples according to guidelines. For women, no such a recommendation is available despite the importance of testosterone in this demographic. The aim of this study is to evaluate the effect of fasting versus non-fasting state on the total testosterone levels in women during the reproductive period. Methods This study was conducted at Faiha Specialized Diabetes, Endocrine and Metabolism Center in Basrah, (Southern Iraq) between January 2022 to November 2022. The total enrolled women were 109; their age was 18-45 years. The presentation was for different complaints; 56 presented for medical consultation with 45 apparently healthy women accompanying the patients as well as eight volunteering female doctors. Testosterone levels were measured by electrochemiluminescence immunoassays using the Roche Cobas e411 platform (Roche Holding, Basel, Switzerland). Two samples were collected from each woman; one was fasting and another was non-fasting the following day, and all samples were taken before 10 am. Results  For all of the participants, the mean ± SD fasting was significantly higher as compared to the non-fasting testosterone (27.39±18.8 ng/dL and 24.47±18.6 ng/dL respectively, p-value 0.01). The mean fasting testosterone level was also significantly higher in the apparently healthy group, (p-value 0.01). In women who presented with hirsutism, menstrual irregularities and or hair fall, no difference was seen in the testosterone levels between fasting and non-fasting states (p-value 0.4).  Conclusion In the apparently healthy women of childbearing age, serum testosterone levels were higher in the fasting versus the non-fasting states. In women who presented with complaints of hirsutism, menstrual irregularities, and or hair fall, the serum testosterone levels were not affected by the fasting states.

Renal Cortical Scarring: 68Ga-PSMA-11 PET Versus 99mTc-DMSA Scanning in a Case of Pyelonephritis.

We previously reported the 68Ga-labeled prostate-specific membrane antigen (PSMA)-11 and 99mTc-dimercaptosuccinic acid (DMSA) images of the first patient in our prospective research comparing renal 68Ga-PSMA-11 PET with 99mTc-DMSA scanning in adults with pyelonephritis. Here, we present the renal cortical 68Ga-PSMA-11 PET and 99mTc-DMSA images of our second patient, who had chronic recurring pyelonephritis and demonstrated renal parenchymal defects secondary to scarring in the kidney.

Recognizing Pinhole Parallax Error for Accurate Localization of Thyroid and Parathyroid Disease.

Parallax error is a pitfall of pinhole scintigraphy that causes mislocalization of the findings. It is important to notice this error on pinhole thyroid and parathyroid scintigraphy and obtain additional images with a parallel-hole collimator to accurately determine the upper and lower margins of large goiters and nodules and the location of ectopic thyroid tissue and parathyroid adenomas. In this teaching case report, we revisit pinhole parallax error, present pinhole and SPECT/CT images of a patient with a large, hyperactive thyroid nodule, and review the literature and potential solutions to this important problem.

Prostate-specific antigen cutoff value for ordering sodium fluoride positron emission tomography/computed tomography bone scan in patients with prostate cancer.

The use of F-18 sodium fluoride (NaF) positron emission tomography/computed tomography (PET/CT) bone scan is increasing because of its higher sensitivity and specificity over standard bone scintigraphy (BS). Studies previously reported a prostate-specific antigen (PSA) cutoff value for ordering standard BS. However, this has not been determined for NaF PET yet. In this study, our goal was to determine a PSA cutoff level for ordering NaF PET/CT bone scan. Newly diagnosed and previously treated prostate cancer patients who had NaF PET/CT scan and PSA measurements within 2 mos of PET study were selected for analysis. When available, other parameters, such as Gleason score (GS), clinical stage, alkaline phosphatase levels, skeletal symptoms, and correlative image findings, were recorded. Receiver operating characteristic (ROC) analysis was performed to determine PSA cutoff values. Sixty-two patients (32 newly diagnosed and 30 previously treated) met the inclusion criteria. Near half of previously treated patients were on hormone therapy. NaF PET/CT was positive in 9 newly diagnosed (PSA mean: 91.6 ng/ml, range: 6.2-226 ng/ml) and in 6 previously treated patients (PSA mean: 146.4 ng/ml, range: 6.6-675 ng/ml). ROC analysis indicated that PSA cutoff value for NaF PET/CT positivity was >20 ng/ml in newly diagnosed and >6 ng/ml in previously treated patients. PSA cutoff value for ordering NaF PET/CT in newly diagnosed patients does not seem significantly different than the previous results for BS (>20 ng/ml). However, we found a lower PSA cutoff value of >6 ng/ml in previously treated patients.

Measurement of solar UVB variations by polysulphone film.

Sheets of polysulphone film have been extensively used as detectors to monitor solar UVB radiation. The advantages of polysulphone detectors are that they are small in size, they have good thermal stability and they are sensitive to UVB radiation. The principal disadvantage of polysulphone detectors is that their spectral sensitivity includes part of the short-wavelength UVA. In this study, we investigate the spectral sensitivity of the polysulphone detector with a series of monochromatic (+/- 2 nm) excitations. We then compare the polysulphone-effective solar radiation with the erythemally effective solar radiation by comparing solar UVB data obtained with polysulphone films with those obtained with a spectroradiometer. From polysulphone data on the seasonal variation of solar UVB radiation, we estimate the corresponding fluctuations of the absorption of the ozone layer. We show that the spectral sensitivity of the polysulphone film is closer to the erythema action spectrum than that indicated by earlier data and that polysulphone detectors can be used to predict the erythema risk of solar UVB. Measurements on solar UVB with polysulphone films and with a spectroradiometer were found to be strongly correlated (R2 > 0.95). Finally, polysulphone-based measurements provide a good measure of the fluctuations of the stratospheric ozone layer.