Spinal antinociceptive effects of adenosine compounds in mice

The effects of injecting ATP, ADP, AMP, adenosine and adenine intrathecally on the pain response induced by the injection of substance P (10 ng/mouse) intrathecally were studied. All the compounds except adenine inhibited the pain response in a dose-related manner. The ED50 values of ATP, ADP, AMP and adenosine were 2.10, 0.93, 0.88 and 0.48 micrograms/mouse, respectively. Pretreatment with theophylline at a dose of 100 mg/kg p.o. markedly diminished all the antinociceptive effects. The effect of adenosine was not affected by s.c. injection of naloxone. These results suggest the existence of adenosine receptors which modulate spinal nociceptive sensory processing, independently of the endogenous opiate system.     

Alteration of leukotriene C4 levels in experimental spinal cord injury]

Leukotriene C4 (LTC4) production in the guinea pig spinal cord following compression injury was determined by radioimmunoassay, in the same way thromboxane B2 (TXB2), a stable metabolite of thromboxane A2 (TXA2), was also measured. When the spinal cords were compressed under a 20 gram weight for 10 minutes, LTC4 levels reached peak values (2.2 +/- 0.4 pmol/g cord) 10 minutes after release, then gradually decreased until being undetectable 60 minutes later. TXB2 levels reached peak values (146.8 +/- 6.2 pmol/g cord) 5 minutes after the release from compression, the TXB2 level then gradually decreased, but remained at about 1/2 of the peak level even 60 minutes after the release. When the spinal cords were compressed with various weights, TXB2 production depended on the degree of compression, while LTC4 production was not affected by the compression injury. The LTC4 production confirmed in the injured spinal cords is suggestive of its relation to secondary disorders after spinal cord injury, spinal edema, in particular.     

School-refusal and social-withdrawal in the clinical setting at a psychiatric medical institution]

Fifty two outpatients, who showed signs of school-refusal-withdrawal at the Shiga Prefectural Psychiatric Institution have been analyzed according to their age, gender, ICD-10 diagnosis, medical evolution, and total number of consultations. A total of 61.5% of the population were male, and they showed a higher average and a wider range of age than female patients. According to the ICD-10 diagnosis, 67.3% were in the group of F40-48 neurotic, stress-related and somatoform disorders, and 11.5% were in the group of F30-39 mood [affective] disorders. Twenty five % of the patients were assumed to have show medical improvement, and 42.3% of the patients continued to have further consultations. This article discusses the possible role of psychiatric medical institutions in supporting cases of school-refusal and social-withdrawal.     

Tachykinin receptor cross-talk. Immunological cross-reactivity between the external domains of the substance K and substance P receptors.

In the present study, we have chemically synthesized peptides which correspond to the four putative extracellular domains of the predicted substance K (SK) receptor protein and raised specific polyclonal antibodies against these peptides. These antibodies were then tested for both structural and functional recognition of epitopes on the substance P (SP) receptor on rat AR42J pancreatic cells and human IM9 lymphoblasts, which express the SP receptor, but not the SK receptor. Antibodies directed against the first, second, and fourth external domains of the predicted SK receptor recognized a 58-kDa protein on AR42J cells. This protein has a molecular weight similar to the previously demonstrated SP receptor on both AR42J cells and IM9 cells. Furthermore, antibodies against the second and fourth extracellular domains significantly inhibited specific 125I-SP binding on both AR42J and IM9 cells, and also significantly inhibited SP-induced mobilization of [Ca2+]i on AR42J cells. These data suggest that the second and fourth extracellular domains of the SK and SP receptors may share common structural motifs for ligand binding and signaling mechanism.     

Scintigraphic detection of recurrence of medullary thyroid cancer

A case of recurrent medullary thyroid cancer (MTC) was evaluated with¹²³I-MIBG,^99mTc(V)-dimercaptosuccinic acid (DMSA), and²⁰¹Tl scintigraphy. This patient had been operated on for MTC in the right thyroid. Recently a left neck mass was noticed, and was suspected of being a. recurrence of MTC based on increased plasma calcitonin (CT) and carcinoembryonic antigen (CEA). He was operated on for the neck mass which revealed MTC, and papillary thyroid cancer was incidentally found in the left thyroid, but the CT and CEA levels remained high, and remaining MTC tumor was suspected. But the location of the tumor was unknown. Although^99mTc(V)-DMSA scintigraphy is generally believed to be superior in sensitivity to¹²³I-MIBG scintigraphy, it did not demonstrate the tumor site but²⁰¹Tl and¹²³I-MIBG did. Furthermore,¹²³I-MEBG scintigraphy has greater specificity for tumors which arise in the neural crest. Judging from the results of this case and cases reported in the literatures, both¹²³I-MIBG and^99mTc(V)-DMSA should be performed in the detection of recurrent MTC.     

Relation between toxicity and carcinogenesis in the kidney: an heuristic hypothesis

Cellular toxicity and cellular carcinogenesis are closely linked. In the kidney, this relationship has been emphasized by the recent discovery of a number of putatively non-mutagenic chemicals that result in acute and chronic toxicity and ultimately in carcinogenesis, especially in the male rat. Many, but not all such compounds, result in renal PTE phagolysosomal overload. At the same time, known metabolites of other carcinogens, e.g., HCBD and FBPA, result in acute renal injury and/or necrosis, followed by chronic tubular disease, interstitial nephritis, and ultimately carcinogenesis. A series of cell mechanisms have been suggested that lead from acute cell injury to altered control of cell division. These mechanisms appear to involve ion deregulation, (especially [Ca2+]i) resulting from a variety of continued injuries, (e.g., oxidative stress from inflammatory cells) and ultimately leading to altered gene expression.     

Performance standards for toric soft contact lenses.

PURPOSE: To simplify the clinical assessment of toric soft contact lens (TSCL) on-eye behavior by establishing a set of standard clinical evaluation techniques. The likely performance range expected among the TSCL wearing population was determined for a series of lens designs and acceptable performance standards indicated for each variable. METHODS: Four prism-ballast, two peri-ballast and one dynamic stabilization TSCL designs were each worn by groups of 20 subjects in a nondispensing study. After 20 min of lens wear, lenses were assessed, in right eyes only, for subjective comfort (100-point scale), lens mislocation (degrees deviation from vertical) and rotational recovery after deliberate 30 degrees mislocation (degrees/10 blinks). The percentage of lenses orienting within +/-10 degrees of target orientation (zero rotation) and the variability of orientation (standard deviation of mislocation) were also calculated for each lens group. RESULTS: Based on partitioning of the data distributions for each variable, performance was designated as excellent, acceptable or poor. Corresponding performance cut-offs were determined at > or =90, 89 to 80, and <80 for subjective comfort, < or =+/-6 degrees , +/-7 degrees to 10 degrees , and >+/-10 degrees for mislocation, >10 degrees /10 blinks, 10 degrees to 6 degrees /10 blinks, and <6 degrees /10 blinks for rotational recovery. For groups of wearers the appropriate cut-offs were > or =90%, 89 to 70%, and <70% of lenses orienting within +/-10 degrees of target orientation and <+/-6 degrees , +/-6 degrees to 10 degrees , and >+/-10 degrees for variability of orientation. CONCLUSION: Techniques suitable for the evaluation of TSCL clinical performance have been described and guidelines for the assessment of such lenses established. In the process, we have identified potential performance differences that may relate to variations in TSCL design.