Magnetic field tomography of coherent thalamocortical 40-Hz oscillations in humans.

This paper introduces the use of magnetic field tomography (MFT), a noninvasive technique based on distributed source analysis of magnetoencephalography data, which makes possible the three-dimensional reconstruction of dynamic brain activity in humans. MFT has a temporal resolution better than 1 msec and a spatial accuracy of 2-5 mm at the cortical level, which deteriorates to 1-3 cm at depths of 6 cm or more. MFT is used here to visualize the origin of a spatiotemporally organized pattern of coherent 40-Hz electrical activity. This coherence, initially observed during auditory input, was proposed to be generated by recurrent corticothalamic oscillation. In support of this hypothesis, we illustrate well-defined 40-Hz coherence between cortical-subcortical sites with a time shift that is consistent with thalamocortical conduction times. Studies on Alzheimer patients indicate that, while a similar activity pattern is present, the cortical component is reduced in these subjects.     

No-scalpel vasectomy: a technique for family physicians.

Family physicians frequently perform outpatient vasectomies. A new approach to exposing the vas deferens, called the no-scalpel vasectomy, results in fewer complications and, the authors believe, improved patient acceptance. This technique, which calls for two specialized instruments, is described, along with patient selection and education issues, vasal occlusion techniques and post-vasectomy follow-up.     

Nerve biopsy findings in Niemann-Pick type II (NPC)

The severe infantile form of Niemann-Pick disease type II was diagnosed in a 4-year-old girl and confirmed by demonstrating in cultured skin fibroblasts a deficiency of low-density lipoprotein-stimulated cholesterol ester synthesis of < 5% of normal. Electrodiagnostic studies revealed changes of a predominantly demyelinating motor and sensory polyneuropathy. Light microscope and ultrastructural examination of a peroneal nerve biopsy showed unique changes. Compacted myelin sheaths were disproportionately thin with marked globular irregularities in single teased nerve fibres and evidence of chronic demyelination. The majority of axons were preserved but axonal spheroids and cytoskeletal abnormalities akin to neuroaxonal dystrophy were noted. Membrane-bound multilobulated lysosomal inclusions of floccular and electron-dense material were present in Schwann cells (SC), endoneurial fibroblasts, macrophages, pericytes and endothelial cells. SC of myelinated fibres were stuffed with whorls of concentric osmiophilic membranous profiles and electron-lucent material. The findings are diagnostic and differ from those of classical Niemann-Pick disease.     

G-protein involvement in muscarinic receptor-stimulation of inositol phosphates in longitudinal smooth muscle from the small intestine of the guinea-pig.

1. Aluminium fluoride (AlF), pertussis toxin (PTX) and cholera toxin (ChTX) have been used to examine the involvement of G-proteins during muscarinic acetylcholine receptor (AChR) stimulation of inositol phospholipid hydrolysis in fragments of longitudinal smooth muscle from the small intestine of the guinea-pig. 2. Carbachol (CCh) induced time- and concentration-dependent increases in [3H]-inositol monophosphates, [3H]-inositol (1,4) bisphosphate, [3H]-inositol (1,3,4) trisphosphate, [3H]-inositol (1,4,5) trisphosphate ([3H]-Ins (1,4,5)P3) and [3H]-inositol tetrakisphosphates measured by h.p.l.c. These increases were inhibited > 95% in the presence of the muscarinic AChR antagonist atropine (0.5 microM). 3. AlF transiently increased the basal levels of [3H]-Ins (1,4,5)P3 but increases in the levels of the other [3H]-inositol phosphates occurred more slowly. CCh-induced increases in the levels of all the [3H]-inositol phosphates were strongly inhibited in the presence of AlF. 4. PTX had no effect on basal levels of any of the [3H]-inositol phosphates but reduced the effects of CCh on these; ChTX had no effects on either basal or CCh-stimulated levels. 5. It was concluded that muscarinic AChR-stimulated increases in the levels of [3H]-inositol phosphates occur via both a PTX-sensitive G-protein and a PTX-insensitive mechanism. The actions of AlF may suggest the involvement of an inhibitory G-protein in the regulation of muscarinic AChR-stimulated inositol phospholipid turnover.     

The efficacy of cyclosporin A, FK-506 and prednisolone to modify the adoptive transfer of experimental allergic encephalomyelitis (EAE).

The in vitro potency of the immunosuppressants Cyclosporin A (CsA), FK-506 and Prednisolone was assessed using the adoptive transfer model of EAE in the Lewis rat. Co-culture of encephalitogen-sensitised splenic leukocytes with Prednisolone did not inhibit the transfer of disease to naive histocompatible recipients despite significant suppression of neuroantigen-stimulated leukocyte proliferation by the drug. The addition of CsA (100 nM) to cultures inhibited the induction of adoptive EAE but a lower dose of the agent (10 nM) did not prevent the development of clinico-histopathological signs of disease. FK-506 (1 nM) was 100 times more effective than CsA at suppressing adoptive EAE thus emphasising the usefulness of the model in determining the relative efficacy of compounds to modify cell-dependent autoimmune disease.     

Comparison of three oral sip-feed supplements in patients with cancer

This study set out to compare the long-term palatability of three oral sip-feed supplements. Sixty patients with various malignancies were randomized to receive one of three products—Build-Up, Fortimel and Fortisip. Participants were encouraged to take as much of the supplements each day for as long as they could manage. At the initial tasting, palatability and acceptability of the products was recorded and this was repeated throughout the trial period. Patients' reasons for discontinuing the trial were noted.
Build-Up was found to be the best-tolerated product of the three. It was taken for a significantly longer time than either Fortimel or Fortisip. There was an indication that Build-Up was more acceptable at the initial tasting than Fortisip but not Fortimel. A smaller proportion of patients stopped taking Build-Up due to flavour-related reasons compared to Fortisip but there was no significant difference between Build-Up and Fortimel. In all, 54% of the patients discontinued the trial for flavour-related reasons. Thirty-five per cent found that the sip-feeds they had been allotted unpalatable at the initial tasting, while 19% stopped the trial due to 'flavour fatigue'. Only 10% of the sample continued taking their allotted product for 90 days or more.     

Associations of alcohol consumption with plasma high density lipoprotein cholesterol and its major subfractions: the Caerphilly and Speedwell Collaborative Heart Disease Studies.

In surveys of 4860 middle-aged men in Caerphilly (South Wales) and Speedwell (Bristol) alcohol consumption has been related to high density lipoprotein (HDL) cholesterol and its major subfractions, HDL2 and HDL3, measured in a single fasting blood sample. The results confirm that high density lipoprotein cholesterol concentration increases as the amount of alcohol regularly consumed increases. The relationship appears to be linear and is independent of age, smoking habit, body mass index, low density lipoprotein cholesterol and plasma total triglyceride. This rise in HDL cholesterol is not mediated through either HDL2 cholesterol or HDL3 cholesterol alone. Both subclasses increase significantly and by similar amounts with increasing alcohol intake.     

Determination of pipothiazine in human plasma by reversed-phase high-performance liquid chromatography

A method is described for the determination of pipothiazine in human plasma, based on reversed-phase HPLC. The method has been applied in a pharmacokinetic study of pipothiazine in six psychiatric patients receiving repeated depot intramuscular injections for six months. A number of compounds likely to be taken concurrently by patients were tested for potential to interfere with the assay. There was no evidence of "dose-dumping" in the period following injection. Comparison of the pharmacokinetic profiles after the first and sixth injections showed no evidence of drug accumulation.     

Calcium events in smooth muscles and their interstitial cells; physiological roles of sparks

The observation of spontaneous sporadic releases of packets of stored calcium made 20 years ago has opened up a number of new concepts in smooth muscle physiology: (1) the calcium release sites are ryanodine and inositol 1,4,5-trisphosphate (IP₃) receptor channels which contribute to cell-wide increases in [Ca²⁺]_i in response to cell depolarization, activation of IP₃-generating receptors, or other stimuli; (2) changes in [Ca²⁺]_i act back on the cell membrane to activate or modulate K⁺, Cl⁻ and cation channel activity so affecting contraction, in arterial smooth muscle for example affecting blood pressure; (3) IP₃ production is voltage dependent and is believed to contribute to pacemaker potentials and to refractory periods which control the rhythmical motility of many hollow organs. Most smooth muscle tissues contain interstitial cells (ICs) in addition to contractile smooth muscle cells (SMCs). The interactions of these internal mechanisms, and in turn the interactions of SMCs and ICs in various smooth muscle tissues, are major factors in determining the unique physiological profiles of individual smooth muscles.