Can activity within the external abdominal oblique be measured using real-time ultrasound imaging?

BACKGROUND

Differences in the function of the anterolateral abdominal muscles have been the subject of much investigation, but primarily using electromyography. Recently changes in thickness of transversus abdominis and internal oblique measured from real-time ultrasound images have been shown to represent activity within these muscles. However it is still unclear if such a change in thickness in external oblique similarly represents activity within that muscle. The purpose of this study was to investigate the relationship between change in thickness and muscle activity in the external oblique using real-time ultrasound and surface electromyography.

METHODS

Simultaneous measurements of electromyography and real-time ultrasound images of external oblique were studied in up to 24 subjects during two tasks compared to the muscle at rest (1) isometric trunk rotation and (2) drawing in the lower abdomen.

FINDINGS

Changes in muscle thickness correlated significantly with electromyography during isometric trunk rotation in the majority of subjects but with a significant difference between subjects. In contrast, the relationship between change in thickness and electrical activity in the muscle when drawing in the lower abdomen was significant in less than 50% of subjects and the muscle often got thinner.

INTERPRETATION

Thickness changes of external oblique can be used as a valid indicator of electromyography activity during isometric trunk rotation, though the relationship is not as good as previously published data for transversus abdominis. Thickness changes of external oblique measured during lower abdominal drawing in cannot be used to detect activity within this muscle.

Transient neutropenia: neutrophil distribution and replacement

Radiolabeled polymorphonuclear (PMN) receptor-specific proteins or peptides lead the list of agents being evaluated for imaging inflammatory foci. Some of these agents induce transient neutropenia. This study was designed to quantify the degree of dose dependency of neutropenia, determine the duration of neutropenia, identify the organs in which these PMNs sequester and ascertain if these PMNs return to the circulation.

METHODS

Rodent anti-PMN (Gr-1) MAb R86-BC5 (IgG-2a) and Balb/c mice served as the model, and PMN nonspecific ME 31.3 (IgG-2a) as a control. Circulating PMN number was determined several times, 30 min prior to and between 1 min and 120 hr after MAb administration. Iodine-125-MAbs provided quantification of circulating activity and tissue distribution as a function of time.

RESULTS

Data showed the severity of neutropenia increased with the amount of MAb administered (> 95% PMNs lost after 150 micrograms versus < 85% after 10 micrograms). Moreover, the recovery time for PMN counts to reach the pretreatment level also increased in a dose-dependent manner (96 hr at 150 micrograms versus 4 hr at 10 micrograms and 2 hr at 2 micrograms). The blood activity, however, which declined quickly with the neutropenia, never rose again with PMN recovery. As a function of time, radioactivity in the study group decreased from all organs except from the liver and spleen, whereas in the control group, it decreased from all organs, including the liver and spleen (e.g., 4 hr liver, 29.4% decrease versus 91.2% decrease in the control group; and spleen, 15.5% decrease versus 63.6% decrease in control group).

CONCLUSION

The degree and duration of neutropenia is dose-dependent. PMNs, lost from the circulation, sequester in the reticuloendothelial system, and do not return to circulation. Therefore, they are not available to image inflammatory foci. The PMN concentration is restored to a pretreatment level in a dose-dependent fashion, presumably by freshly released PMNs from bone marrow.

Prevalence of human immunodeficiency virus (HIV) antibodies in tuberculosis patients in Lagos, Nigeria

To establish the prevalence of HIV antibodies in patients with pulmonary tuberculosis, 536 new cases presenting with symptoms of bronchopulmonary disorders were randomly selected from the six referral chest clinics in Lagos and screened for tuberculosis and HIV infections. Sputum and serum samples were obtained from all the patients. The sputum samples were examined for acid-fast bacilli (AFB) by both microscopy and culture. The sera were screened for HIV-1 and HIV-2 antibodies by ELISA and confirmed by Western blot (WB). Of the 536 cases studied, 188 (35%) were positive for AFB while 13 (2.4%) were seropositive for HIV. Correlation between the AFB and HIV results revealed that 10 (5.3%) of the 188 AFB positives were also seropositive for HIV as compared to 3 (0.9%) in the 348 AFB negative cases. The difference in the HIV seroprevalence rates in the two groups was statistically significant (P < 0.001). The recorded higher frequency of HIV infections in the AFB positives strongly suggested some level of interaction between TB and HIV infections in Lagos. Infections with HIV-2 were more prevalent than HIV-1 in the patients with HIV and TB. No case of dual infection with HIV-1 and HIV-2 was recorded in this group of patients. However, in the 3 HIV-seropositive patients within the control group (non-tuberculosis patients), 2 (67%) were positive for both HIV-1 and HIV-2 while 1 (33%) was positive for HIV-2 only. Mycobacterium tuberculosis (70%), M. avium (20%) and M. kansasii (10%) were the mycobacteria strains isolated from the HIV/TB infected patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Preparation and biodistribution of copper-67 complexes with tetradentate Schiff-base ligands

Uncharged, lipophilic, low molecular weight copper complexes labeled with generator-produced copper-62 are of interest as potential radiopharmaceutials for imaging the brain with positron emission tomography (PET). We report here the synthesis and biodistribution of a series of [67Cu]copper(II) complexes with tetradentate N2O2(2-)Schiff-base ligands. The compounds studied varied in lipophilicity from log P = 1.7 to log P = 3.6, where P is the octanol/water partition coefficient. In rat biodistribution studies the tracers were generally found to penetrate the blood-brain barrier following intravenous injection, but some far better than others. For closely related compounds brain uptake at 1 min postinjection increased with increasing lipophilicity, although log P was clearly not the sole determinant of high brain uptake. Substantial variations were also observed in the rate at which these various compounds are cleared from brain, with a few exhibiting the prolonged cerebral retention of tracer that would be desired for imaging with 62Cu and PET.

Acute toxicity and mutagenicity of the copper complex of pyruvaldehyde-bis (N-4-methylthiosemicarbazone), Cu-PTSM

Cu-PTSM is a potential imaging agent for the heart and brain when labeled with either 64Cu or 62Cu. Unlabeled Cu-PTSM was evaluated for its acute toxicity and mutagenicity. Cu-PTSM had an i.v. LD50 of 26 mg kg-1 in the rat and 2 mg kg-1 in the rabbit. At necropsy, rats exhibited severely hemorrhagic lungs, histological findings of acute pulmonary congestion, hemorrhage and edema, and mild congestion in kidney, liver and brain. The rabbit displayed marked polymorphonuclear infiltration in alveoli, peribronchial and periarterial areas with marked macrophage hyperplasia, congestion and mild hemorrhage into alveolar spaces. No effects were found in kidney, liver, testes or brain. Administration of 2.16 micrograms kg-1 day-1 for 5 days per week for 2 weeks resulted in no changes in histopathology, hematology or clinical chemistry parameters. This daily dose is at least 300 times the diagnostic dose intended for use in man. Cu-PTSM was not mutagenic when tested in the absence of S9 supernatant, but elicited a weakly mutagenic response in the presence of S9. Since acute effects in the lung occur at doses approaching 300,000 times the diagnostic dose, it is highly unlikely that the clinical use of Cu-PTSM would result in any acute adverse effects.

Structure-activity relationships for metal-labeled blood flow tracers: comparison of keto aldehyde bis(thiosemicarbazonato)copper(II) derivatives

Radiocopper-labeled pyruvaldehyde bis(N4-methylthiosemicarbazonato)copper(II), Cu[PTSM], is under investigation as a radiopharmaceutical for evaluation of regional blood flow in the brain, heart, and kidneys because it affords relatively high levels of radioactivity in these organs upon intravenous injection, followed by prolonged tissue retention of the radiolabel. To probe and differentiate the physicochemical properties that are critical for blood-brain barrier (BBB) penetration and tissue retention in complexes of this type, 17 67Cu-labeled copper(II) bis(thiosemicarbazone) derivatives of Cu[PTSM] have been prepared and characterized, focusing on the bis(thiosemicarbazone), bis(N4-methylthiosemicarbazone), bis(N4-dimethylthiosemicarbazone), and bis(N4-ethylthiosemicarbazone) derivatives of several alkylglyoxals (R(1) = Me, Et, n-Pr, i-Pr, n-Bu, or Me(EtO)CH) and phenylglyoxal. The compounds studied varied in lipophilicity from log P = 0.75 to log P = 3.5 (where P is the octanol/water partition coefficient). In rat biodistribution studies the N4-methylthiosemicarbazone (R(1)TSM) and N4-dimethylthiosemicarbazone (R(1)TSM2) complexes always show comparable cerebral uptake at 1 min postinjection (iv) for any given R(1) group, while the thiosemicarbazone (R(1)TS) complex always penetrates the BBB less efficiently. Comparison of the various Cu[R(1)TS] derivatives shows that their brain uptake does tend to increase with increasing lipophilicity over the range 0.75 less than log P less than 2.4, although it never reaches that of the N4-alkylated derivatives. The Cu[R(1)TS] and Cu[R(1)TSM] complexes are found to exhibit prolonged cerebral retention of activity, consistent with their known susceptibility to reductive decomposition by intracellular sulfhydryl groups, while the more inert Cu[R(1)TSM2] complexes clear from the brain relatively rapidly. Tracer clearance kinetics in the heart and kidney are similar to those observed for the brain with each of the tracers examined.

Evaluation of a potential generator-produced PET tracer for cerebral perfusion imaging: single-pass cerebral extraction measurements and imaging with radiolabeled Cu-PTSM

Copper(II) pyruvaldehyde bis(N4-methylthiosemicarbazone) (Cu-PTSM), copper(II) pyruvaldehyde bis(N4-dimethylthiosemicarbazone) (Cu-PTSM2), and copper(II) ethylglyoxal bis(N4-methylthiosemicarbazone) (Cu-ETSM), have been proposed as PET tracers for cerebral blood flow (CBF) when labeled with generator-produced 62Cu (t1/2 = 9.7 min). To evaluate the potential of Cu-PTSM for CBF PET studies, baboon single-pass cerebral extraction measurements and PET imaging were carried out with the use of 67Cu (t1/2 = 2.6 days) and 64Cu (t1/2 = 12.7 hr), respectively. All three chelates were extracted into the brain with high efficiency. There was some clearance of all chelates in the 10-50-sec time frame and Cu-PTSM2 continued to clear. Cu-PTSM and Cu-ETSM have high residual brain activity. PET imaging of baboon brain was carried out with the use of [64Cu]-Cu-PTSM. For comparison with the 64Cu brain image, a CBF (15O-labeled water) image (40 sec) was first obtained. Qualitatively, the H2(15)O and [64Cu]-Cu-PTSM images were very similar; for example, a comparison of gray to white matter uptake resulted in ratios of 2.42 for H2(15)O and 2.67 for Cu-PTSM. No redistribution of 64Cu was observed in 2 hr of imaging, as was predicted from the single-pass study results. Quantitative determination of blood flow using Cu-PTSM showed good agreement with blood flow determined with H2(15)O. This data suggests that [62Cu]-Cu-PTSM may be a useful generator-produced radiopharmaceutical for blood flow studies with PET.