Placental transfer of hexachlorophene (HCP) in the marmoset monkey (Callithrix jacchus)

Autoradiography was used to study the distribution of 2,2'-14C-methylene-bis-(3,4,6-trichlorophenol) (HCP) in pregnant marmoset monkeys in early (day 30-50) and late (around day 120) gestation and in a newborn (11 days old) pup. Radioactivity was present in the conceptus at all stages of gestation, although the foetal concentration was lower than the maternal. In the embryo an accumulation was observed in the neural tube and in the embryonic membranes. In the late foetus and newborn monkey the highest concentration of radioactivity was found in the liver and the intestinal contents. The brain of the adult and newborn animals showed low concentration. A partial blood-brain barrier was present in the late foetus but, in relation to other tissues, the foetal brain concentration was higher than that of the mother.     

Relationship between cardiovascular neurones and descending antinociceptive pathways in the rostral ventrolateral medulla of the cat

It has been previously reported that injection of neuroexcitatory compounds into the rostral ventrolateral medulla (RVLM) can produce an inhibition of nociceptive reflexes, often associated with a rise in arterial blood pressure. The aim of this study was to determine whether the subretrofacial (SRF) nucleus, which is a highly circumscribed group of cells within the RVLM known to play a major role in cardiovascular regulation also has an antinociceptive function. In barbiturate-anaesthetised and paralysed cats, unilateral microinjections of the neuroexcitatory compound sodium glutamate (8-20 nl of 0.5 M solution) into the SRF nucleus produced large increases in mean arterial pressure but had only small and inconsistent effects on the simultaneously measured ventral root responses to stimulation of primary afferent C-fibres. On the other hand, glutamate microinjections into RVLM sites closely adjacent to the SRF nucleus, or into the nucleus raphe magnus, produced powerful inhibition of the C-fibre evoked response in the ventral root which was accompanied by no or only small changes in arterial pressure. It is concluded that the SRF pressor cells do not exert any control over nociceptive spinal reflexes, but that such a function may be served by cells in closely adjacent parts of the RVLM. Moreover, the method of recording C-fibre evoked responses in ventral roots as a measure of the magnitude of nociceptive spinal reflexes, combined with the glutamate microinjection procedure, was shown to have a sufficient resolution to allow an accurate mapping of the location of antinociceptive cell groups within the ventrolateral medulla.     

Uptake of lead by Pomphorhynchus laevis cystacanths in Gammarus pulex and immature worms in chub (Leuciscus cephalus)

The uptake of lead by cystacanths of the acanthocephalan Pomphorhynchus laevis in naturally infected amphipods, Gammarus pulex, and by immature parasites in experimentally infected fish, Leuciscus cephalus, was examined following 3-week experimental exposures (0.01 and 0.1 mg l⁻¹ Pb²⁺). Both G. pulex and the cystacanths of P. laevis accumulated lead but concentrations in the parasites were lower than in the host tissues at the low lead dose and significantly lower at the high dose. P. laevis from chub exposed to 0.01 mg l⁻¹ lead contained significantly more of the metal than the tissues of their host. Interestingly, there was an increase in the mean lead levels in the parasites from the control chubs which was concurrent with a decrease in host tissue concentrations. The results of this experimental study therefore confirm previous suggestions that heavy metals are predominantly accumulated by acanthocephalans inside the fish definitive host and not by␣cystacanths in the haemocoel of the amphipod intermediate host. The microhabitat of the parasite is therefore of primary importance rather than its developmental stage. Furthermore, metal concentrations in adult acanthocephalans will respond rapidly to changes in environmental exposure of their hosts. Received: 15 November 1997 / Accepted: 11 February 1998     

Routine clinical application of the lymphocyte fluorescence polarization test for malignant disease

The technique of Lymphocyte Fluorescence Polarization (LFP) can confirm or exclude the presence of malignant disease. The results from tests on a total of 566 subjects showed a false-positive rate of 3.8% and a false-negative rate of 2.2%. The LFP test has been used as an aid in the differential diagnosis of patients whose symptoms are not typical of primary or recurrent malignant disease. In over 40 such cases there has been total agreement between the LFP results and subsequent clinical or pathological investigations. The LFP Test has been used to monitor the response of cancer patients to various therapeutic regimes. Ovarian cancer patients giving negative LFP results after treatment with Cisplatin have been found free of disease at laparotomy, indicating that LFP may be an acceptable alternative to the surgical investigation. The LFP test has been shown to provide information of much value in the management of patients with malignant disease.     

Muscle necrosis in the extremities: evaluation with Tc-99m pyrophosphate scanning--a retrospective review

A retrospective review was done of 34 extremities studied between 1981 and 1985 with technetium-99m pyrophosphate scanning; 22 were subsequently amputated. Results of detailed pathologic examination or immediate postoperative examination of the resected extremity were available in 16 cases. In these cases, scanning had allowed correct prediction of the level of amputation and of the specific areas of muscle infarction in 13 cases. In the one case in which amputation was performed for infection rather than muscle necrosis, the lack of necrosis was correctly predicted with the scan. The limited results of this study indicate that the Tc-99m pyrophosphate scan allows the location of necrotic muscle to be predicted accurately and may therefore be a useful adjunct in determining the best level for ultimate amputation. Special caution is required in those cases in which muscle necrosis is due to acute causes (e.g., traumatic thrombosis) rather than chronic vascular disease.     

A proposed algorithm for the management of pain following spinal cord injury

STUDY DESIGN: Review. OBJECTIVES: To review published articles on the assessment, diagnosis and treatment of pain following spinal cord injury (SCI) and to synthesise evidence from these materials to formulate and propose a systematic approach to management. METHODS: Relevant articles regarding the treatment of pain were identified from electronic databases using the search terms (('spinal cord injury' or 'spinal cord injuries') and 'pain') and both ('treatment') and ('randomised controlled trials'). Relevant articles were also identified through citations in indexed journal publications and book chapters on this topic. RESULTS: Review of the literature indicates that there are a large variety of treatments used in the management of pain following SCI with a small number supported by strong evidence for effectiveness. A treatment algorithm is proposed based on identification of underlying pain contributors and application of appropriate treatment. CONCLUSION: Although there are relatively few studies clearly indicating efficacy in this population, an algorithm for the management of pain following SCI might assist to maximise our effectiveness in the treatment of this condition. It is recognised that choice of treatment is also determined by factors such as medication availability, cost and side effects as well as the preferences and characteristics of the person being treated. Nevertheless, an algorithm is proposed as a way to synthesise our current level of knowledge, identify gaps for further study and aid in the management of this difficult problem.     

Pulse sequence optimization for MR imaging using a paramagnetic hepatobiliary contrast agent

Paramagnetic agents enhance contrast between tissues in magnetic resonance (MR) imaging by altering tissue relaxation times. The effect of these changes on MR image intensity depends in part on the choice of operator-controlled pulse sequence parameters. With the newly described paramagnetic hepatobiliary contrast agent, iron(III) ethylenebis-(2-hydroxyphenylglycine), Fe(EHPG)-, an in vivo experimental analysis of pulse sequence optimization was performed on the rat. We compared the enhancement of the liver divided by background noise, EL/N, of standard inversion-recovery (IR) and spin-echo (SE) T1-weighted pulse sequences and several pulse sequences theoretically predicted to have improved EL/N. Optimization of the echo time (TE = TEmin) gave a substantial (greater than 60%) increase in EL/N over the standard IR and SE pulse sequences. Images obtained with optimized repetition rate and inversion time gave only a slight additional improvement. Within the uncertainties of our relaxation measurements, the measured changes in EL/N with pulse sequence optimization corresponded well with theoretical predictions. With the experimental and theoretical data, the importance of using a short echo time to obtain maximal T1 contrast in contrast-enhanced MR imaging and the relative merits of optimized SE versus IR pulse sequences for contrast-enhanced MR imaging are discussed.