Non-Hodgkin's lymphoma in childhood presenting as thyroid enlargement

The authors report a case of a 10-year-old girl with early involvement of the thyroid gland by non-Hodgkin's lymphoma, an uncommon site of presentation of childhood lymphomas. In pediatrics, thyroid enlargement is more often caused by lymphocytic thyroiditis. The good response to therapy, in spite of the advanced stage of the disease, is noted.     

Selective lesions of rabbit extraocular muscles injected with the anti-AChR immunotoxin saporin-mAb 73

PURPOSE: To evaluate the effects on extraocular muscles of a skeletal muscle-specific immunotoxin, saporin-mAb 73, as an alternative to botulinum toxin to induce a permanent correction of oculo-facial dystonias or some forms of ocular motility disorders. METHODS: An immunotoxin was prepared with a monoclonal antibody (mAb 73) against acetylcholine receptors of skeletal muscle, linked to saporin, a type 1 ribosome-inactivating protein (RIP) from Saponaria officinalis. Sixteen New Zealand white rabbits were treated with a single injection of immunotoxin directly into the medial rectus muscle of one eye. Four different dosages of 2, 5, 20, or 50 ng saporin-mAb 73 were used. The rabbits were sacrificed at two, 7 and 14 days post-injection. The medial rectus muscle and the retractor bulbi muscle of both the injected and the fellow eyes were taken and serial sections were examined by light microscopy in a blinded manner. RESULTS: Saporin-mAb 73, even at the dosage of 2 ng, brought about focal damage in the extraocular muscles of rabbits without histological changes in adjacent muscles. The histological examination revealed necrotic/apoptotic lesions restricted to the sites of inoculation and largely infiltrated by macrophages. No evident inflammatory reaction was detected at any time and neutrophils were substantially absent. At 14 days after injection, necrosis/apoptosis was still evident and the sclerotic reaction was minimal. CONCLUSIONS: The immunotoxin saporin-mAb 73 injections into the extraocular muscles of rabbits caused focal damage to the muscles. There was no significant inflammatory reaction and muscle fiber loss was present even at the lower doses. Although the lesions were followed for only 14 days, our results suggest that saporin-mAb 73 has potential to cause safe focal muscle damage but longer-term follow-up are needed to investigate the persistence of muscle weakness.     

Recent advances in hormonal male contraception

Hormones inhibit fertility in men by suppressing sperm production. Testosterone-enanthate induced azoospermia has proven to provide optimal contraceptive protection. Preliminary studies have shown that testosterone alone or androgen-progestin combinations induce profound sperm suppression in the Eastern and white populations, respectively. Thus, these regimens may represent viable options for male contraception. New long-acting androgen formulations represent a major advancement in this field, allowing for the development of more acceptable and effective regimens.     

The neural basis of functional brain imaging signals

The haemodynamic responses to neural activity that underlie the blood-oxygen-level-dependent (BOLD) signal used in functional magnetic resonance imaging (fMRI) of the brain are often assumed to be driven by energy use, particularly in presynaptic terminals or glia. However, recent work has suggested that most brain energy is used to power postsynaptic currents and action potentials rather than presynaptic or glial activity and, furthermore, that haemodynamic responses are driven by neurotransmitter-related signalling and not directly by the local energy needs of the brain. A firm understanding of the BOLD response will require investigation to be focussed on the neural signalling mechanisms controlling blood flow rather than on the locus of energy use.     

Cardiac tomography with 99mTc-tetrofosmin after nitrate administration in patients with ischemic cardiopathy and left ventricular dysfunction

PURPOSE: To investigate the role of technetium-99m (99mTc) tetrofosmin single-photon emission Computed Tomography (SPECT) associated with nitrate administration in the detection of hypoperfused but still viable myocardium in patients with chronic coronary artery disease and left ventricular (LV) dysfunction. MATERIAL AND METHODS: Twenty-two patients (mean age 54 +/- 11 years) with coronary artery disease, previous myocardial infarction and LV dysfunction (LV ejection fraction 38 +/- 13%) were examined. On different days all patients underwent 99mTc tetrofosmin (740 MBq) SPECT under control conditions at rest and after sublingual nitroglycerin administration (10 mg). Regional tetrofosmin activity was quantitatively measured in 22 myocardial segments per patient. In each segment, tracer uptake was expressed as a percentage of the region with the peak activity. RESULTS: Under control conditions, 267 myocardial segments (55%) showed normal tetrofosmin uptake (> 70% of peak activity), 107 segments (22%) showed a moderate reduction (51-70%) and 110 segments (23%) a severe reduction (< or = 50%) in tracer uptake. Among the 110 segments with a severe reduction in tetrofosmin uptake, 20 (18%) showed increased tracer uptake > or = 10% of after nitrate administration (from 44 +/- 5% to 58 +/- 3%, p < 0.0001). The remaining 90 (82%) segments with a severe reduction in tetrofosmin uptake did not show any change after nitroglycerin administration (from 38 +/- 9% to 39 +/- 8%, p = ns). CONCLUSIONS: In patients with chronic coronary artery disease and LV dysfunction, tetrofosmin cardiac SPECT associated with sublingual nitrate administration allows the detection of severely hypoperfused but still viable myocardium.