Effects of testosterone replacement in human immunodeficiency virus-infected women with weight loss.

The objective of this study was to determine whether physiological testosterone replacement increases fat-free mass (FFM) and muscle strength and contributes to weight maintenance in HIV-infected women with relative androgen deficiency and weight loss. Fifty-two HIV-infected, medically stable women, 18-50 yr of age, with more than 5% weight loss over 6 months and testosterone levels below 33 ng/dl were randomized into this double-blind, placebo-controlled trial of 24-wk duration. Subjects in the testosterone group applied testosterone patches twice weekly to achieve a nominal delivery of 300 mug testosterone over 24 h. Data were evaluable for 44 women. Serum average total and peak testosterone levels increased significantly in the testosterone group, but did not change in the placebo group. However, there were no significant changes in FFM (testosterone, 0.7 +/- 0.4 kg; placebo, 0.3 +/- 0.4 kg), fat mass (testosterone, 0.3 +/- 0.7 kg; placebo, 0.6 +/- 0.7 kg), or body weight (testosterone, 1.0 +/- 0.9 kg; placebo, 0.9 +/- 0.8 kg) between the two treatment groups. There were no significant changes in leg press strength, leg power, or muscle fatigability in either group. Changes in quality of life, sexual function, cognitive function, and Karnofsky performance scores did not differ significantly between the two groups. High-density lipoprotein cholesterol levels decreased significantly in the testosterone group. The patches were well tolerated. We conclude that physiological testosterone replacement was safe and effective in raising testosterone levels into the mid to high normal range, but did not significantly increase FFM, body weight, or muscle performance in HIV-infected women with low testosterone levels and mild weight loss. Additional studies are needed to fully explore the role of androgens in the regulation of body composition in women.

A novel high-performance fourier transform ion cyclotron resonance cell for improved biopolymer characterization.

A new trapped ion cell design for use with Fourier transform ion cyclotron resonance mass spectrometry is described. The design employs 15 cylindrical ring electrodes to generate trapping potential wells and 32 separately assignable rod electrodes for excitation and detection. The rod electrodes are positioned internal to the ring electrodes and provide excitation fields that are thereby linearized along the magnetic field over the entire trapped ion volume. The new design also affords flexibility in the shaping of the trapping field using the 15 ring electrodes. Many different trapping well shapes can be generated by applying different voltages to the individual ring electrodes, ranging from quadratic to linearly ramped along the magnetic field axis, to a shape that is nearly flat over the entire trap volume, but rises very steeply near the ends of the trap. This feature should be useful for trapping larger ion populations and extension of the useful range of ion manipulation and dissociation experiments since the number of stages of ion manipulation or dissociation is limited in practice by the initial trapped ion population size. Predicted trapping well shapes for two different ring electrode configurations are presented, and these and several other possible configurations are discussed, as are the predicted excitation fields based on the use of rod electrodes internal to the trapping ring electrodes. Initial results are presented from an implementation of the design using a 3.5 T superconducting magnet. It was found that ions can be successfully trapped and detected with this cell design and that selected ion accumulation can be performed with the utilization of four rods for quadrupolar excitation. The initial results presented here illustrate the feasibility of this cell design and demonstrate differences in observed performance based upon different trapping well shapes.

High-Speed TOFMS Detection for Capillary Electrophoresis.

A new, high-speed data acquisition system was tested for high storage rate time-of-flight mass spectrometry (TOFMS) detection in capillary electrophoresis (CE). For high spectral acquisition rates of 4 kHz, a spectral storage rate of 80 spectra s(-)(1) was achieved. The resulting detection limit was in the low amol range (10-25 amol) for continuous infusion investigations.

Electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry at 11.5 tesla: instrument design and initial results.

Initial results obtained using a new electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) mass spectrometer operated at a magnetic field 11.5 tesla are presented. The new instrument utilized an electrostatic ion guide between the ESI source and FTICR trap that provided up to 5% overall transmission efficiency for light ions and up to 30% efficiency for heavier biomolecules. The higher magnetic field in combination with an enlarged FTICR ion trap made it possible to substantially improve resolving power and operate in a more robust fashion for large biopolymers compared to lower field instruments. Mass resolution up to 10(6) has been achieved for intermediate size biopolymers such as bovine ubiquitin (8.6 kDa) and bovine cytochrome c (12.4 kDa) without the use of frequency drift correction methods. A mass resolution of 370,000 has been demonstrated for isotopically resolved molecular ions of bovine serum albumin (66.5 kDa). Comparative measurements were made with the same spectrometer using a lower field 3.5-tesla magnet allowing the performance gains to be more readily quantified. Further improvements in pumping capacity of the vacuum system and efficiency of ion transmission from the source are expected to lead to further substantial sensitivity gains.

Ultrahigh-speed calculation of isotope distributions.

This paper introduces an ultrahigh-speed algorithm for calculating isotope distributions from molecular formulas, elemental isotopic masses, and elemental isotopic abundances. For a given set of input data (molecular formula, elemental isotopic masses, and elemental isotopic abundances), and assuming round-off error to be negilgible, the new algorithm rigorously produces isotope distributions whose mean and standard deviation are "correct" in the sense that an error-free algorithm would produce a distribution having the same mean and standard deviation. The peak heights are also "correct" in the sense that the height of each nominal isotope peak from the ultrahigh-speed calculation equals the integrated peak area of the corresponding nominal isotope peak from an exact calculation. As a consequence of these properties, the algorithm generally places isotope peaks within millidaltons of their true centroids. The method uses Fourier transform methods and relates closely to two other recently introduced algorithms. The suite of capabilities provided by these three algorithms is sufficient to solve an extremely wide range of problems requiring isotope distribution simulation.

A high performance low magnetic field internal electrospray ionization-fourier transform ion cyclotron resonance mass spectrometer.

A new in-magnetic field electrospray ionization (ESI) and Fourier transform ion cyclotron resonance mass spectrometer has been constructed and evaluated. This system is characterized by the use of multiple concentric cryopanels to achieve ultrahigh vacuum in the ion cyclotron resonance cell region, a probe-mounted internal ESI source, and a novel in-field shutter. Initial experiments demonstrate high resolution mass measurement capability at a field strength of 1 T. Mass resolution of 700,000 has been obtained for the 3+ charge state of Met-Lys-bradykinin (at m/z 440) generated by electrospray ionization. When electron impact ionization was employed, resolution in excess of 9,200,000 was achieved for nitrogen molecular ions (N 2 (+) ). Isotopic resolution for molecular ions of bovine ubiquitin (MW=8565 µ) also was achieved by using small ion populations.

Dissociation of tetrameric ions of noncovalent streptavidin complexes formed by electrospray ionization.

The noncovalent tetrameric association of the protein streptavidin formed by electrospray ionization (ESI) mass spectrometry has been observed intact and dissociated in the gas phase. An extended mass-to-charge ratio range quadrupole mass spectrometer was employed to examine the effects of harsher conditions in the ESI atmosphere-vacuum interface region on the streptavidin tetramer. Thermally induced dissociation caused the mass spectra to exhibit a series of complementary monomer and trimer ions that correspond to decomposition of the tetrameric species. Similar results were obtained with tandem mass spectrometric experiments on a Fourier transform ion cyclotron resonance mass spectrometer by application of sustained off-resonance irradiation (SORI) on a selected tetrameric charge state. The technique of single-frequency quadrupole excitation was used to accomplish selected-ion accumulation of the 14 + charge state of the tetramer during ion injection. Subsequent low energy SORI combined with broadband quadrupole cooling produced the 7 + monomer and 7 + trimer species, as well as the 6 + monomer and 8 + trimer complementary ions. The observed asymmetric breakup of the tetramer is qualitatively explained by using physical models.

Prostatic acid phosphatase, beta-glucuronidase and prostate specific antigen assays in fine needle aspirates from benign and malignant prostates.

Enzymatic assays for tartrate-sensitive acid phosphatase and beta-glucuronidase, and radio-immunoassay for prostate-specific antigen, were modified for application to fine-needle aspirate samples from benign and malignant human prostates. When compared to samples from benign prostates, the ratio of acid phosphatase to beta-glucuronidase activities was significantly decreased in needle aspirates from malignant prostates. Prostate-specific antigen values in the aspirates did not correlate with malignancy.

Serum lymphocyte adherence inhibition test in bladder cancer patients.

In 29 patients with a history of bladder cancer cystoscopic determination of tumor status was correlated with the results of a serum modified capillary tube lymphocyte adherence inhibition test. With donor lymphocytes from 3 healthy volunteers as indicator cells, patient sera were added to a butanol extract of the T-24 tissue-cultured bladder carcinoma cell line. Lymphocyte adherence inhibition of more than 15 per cent was selected as positive. Mean values for 17 cases positive for tumor were 26.6 +/- 14.1 per cent compared to 10.0 +/- 6.8 per cent for 18 cases negative for tumor. False positive and false negative values at this cutoff averaged 19 and 14 per cent, respectively, and there was no significant difference in the individual results of the 3 donor leukocytes. Serial examinations of 6 patients had lymphocyte adherence inhibition values consistent with the changes in tumor status. These results suggest that the serum lymphocyte adherence inhibition test correlates well with clinical tumor status and, therefore, may serve as a useful tumor marker in patients with bladder cancer.