Effects of halothane on the synthesis of neurotransmitter amino acids in mouse brain

The effects of halothane on the synthesis of the three major neuroactive amino acids (θ–aminobutyric acid, aspartate and glutamate) and glutamine, which is closely related metabolically, were investigated in mouse brain using a labelled precursor ([¹³C]glucose) and a gas chromatography–mass spectrometry system. The ratios of newly synthesised amino acids were increased relative to baseline values when animals were exposed to 1% halothane, and decreased when they were exposed to 2% halothane. These findings suggest that halothane affects the synthesis of neurotransmitter amino acids in a concentration–dependent manner, without discrimination between excitatory and inhibitory amino acids.     

Study of Tumor-Associated Blastogenic Reactivity of Peripheral Blood Lymphocytes and Regional Lymph Node Lymphocytes in Human Malignancy

The in vitro blastogenic responses of peripheral blood lymphocytes(PBL) and the regional lymph node lymphocytes (LNL) from cancerpatients to autochthonous tumor cells (TC) were investigated.A positive lymphocyte response to autochthonous TC was observedin 23% (6/26) for PBL and 34% (9/26) for LNL. There seemed tobe an inverse relationship between PBL and LNL responses toautochthonous TC. There was no significant difference betweenPBL and LNL responses to autochthonous TC according to the primarysite of the tumor. Analysis of PBL and LNL responses to autochthonousTC according to the extent of the disease revealed that LNLwere definitely more reactive than PBL in patients with a primarytumor that had not spread to the regional lymph nodes.     

The concept of interface related to services for handicapped families

Summary The Warnock Report (1978) concept that a 'link person' was needed to liaise services to handicapped families was investigated with a one in three sample ( n = 120) of parents with mentally handicapped children in a county in South Wales. The findings show that whilst almost half the parents considered a social worker to be in the best position to undertake this overall coordinating function, there remains a considerable gap between theory and practice.     

Clinical variability of congenital myopathy with type I fiber atrophy: A long-term observation of three cases

The variable clinical courses of three cases of congenital fiber type disproportion (CFTD) over a period of 10 years are presented. All showed improvement in early childhood, but subsequently, varying degrees of deterioration were noted: specifically, marked deterioration in case 2 and decreased muscle strength in case 3. Maximal motor function levels were attained differently among the cases. Histological findings included type 1 fiber hypotrophy and increased internal nuclei in common in all cases. Fine structural changes, such as patchy areas of myofibrillar degeneration, were noted in cases 1 and 2 (second biopsy), and cytoplasmic bodies were seen in case 2 (second biopsy). Myotubes were noted in case 3. The degree of cyto-architectural changes did not correlate with clinical severity. The heterogeneity of CFTD is also discussed.     

Immunoreactive' TSH' in urinary concentrates of Graves' disease patients: a radioimrnunoassay artefact

Abstract. A double antibody radioimmunoassay was used to analyse immunoreactive thyrotrophin in urinary concentrates from fourteen patients with hyperthyroid-ism due to Graves' disease, in three subjects with primary hypothyroidism, and in six normal subjects. Immunoreactive thyrotrophin was detectable in eleven subjects with Graves' disease, in one subject with primary hypothyroidism, and in four normal subjects. The mean urinary thyrotrophin concentration was significantly higher in Graves' disease (492 ± 99.9 μU/24h (SEM) ( n = 11)) than in normal subjects ((177 ± 26.4 μU/ 24 h (SEM) ( n = 4) (P<0.01)). The fact that bioassay-able thyrotrophin was undetectable in urinary concentrates in Graves' disease and that radioimmunoassay of other polypeptide hormones in urine can be influenced nonspecifically, led to the suspicion that the immunoreactive thyrotrophin measured in urinary concentrates was an assay artefact. This was strongly supported by the absence of a radioimmunoassayable thyrotrophin in urinary concentrates after extensive dialysis (96 h) without loss of added ¹³¹I-labelled thyrotrophin, differences between the elution pattern on Sephadex G-100 columns of ¹³¹I-labelled thyrotrophin and the immunoreactive thyrotrophin detected after chromato-graphy of the urinary concentrates on the same column, and the ability of different salts in various concentration to mimic dose-response curves in the radioimmunoassay for thyrotrophin as well as for thyroglobulin. In addition, since urinary proteins and IgG levels were elevated in concentrates of Graves' disease when compared with normal subjects, it has been suggested that the filtering mechanism of kidney is affected in Graves' disease, a disorder which has recently been associated with circulating antigen—antibody complexes.     

Current Status and Potential Applications of the Harts Removable Stent

Permanent intracoronary scents have demonstrated considerable efficacy in the treatment of PTCA-induced abrupt arterial occlusion, suboptimal dilatation, and restenosis. Despite their benefit, permanent stents have significant limitations including subacute thrombosis, need for anticoagulation with resultant vascular complications, prolonged hospitalization, and high costs. Temporary stem's have the potential for achieving many of the beneficial effects of permanent stenting without some of the iatrogenic complications. The HARTS (Heat Activated Removable Temporary Stent) removable stent employs the shape memory alloy Nitinol, and has the properties of being balloon deployable, but recoverable to a preset "memory" shape by heating it with warmed crystalloid solution. Preclinical experience first with a wire stent design and more recently with a slotted tubular design, has demonstrated the feasibility of implanting and recovering the HARTS device. Speculative applications of this technology include: treatment of acute postangioplasty occlusion and suboptimal angioplasty results; "stentoplasty"—the application of a temporary stent for several hours at the time of a primary angioplasty; and reduction of restenosis rate by inhibition of elastic recoil following short-term (hours) stenting. Further, the HARTS device may be an important vehicle for local delivery of drugs or other biologically active agents to the arterial wall. All research to date has been preclinical and controlled clinical trials will be necessary to define the safety, efficacy, and potential applications of the HARTS removable stent.     

BUCKTHORN NEUROPATHY: EFFECTS OF INTRANEURAL INJECTION OF KARWINSKIA HUMBOLDTIANA TOXIN

Ingestion of the endocarp of the coyotillo fruit, Karwinskia humboldtiana , a shrub of the buckthorn family, causes 'Buckthorn neuropathy' in man and animals. Two neurotoxic compounds T496 and T544 were isolated from the endocarp and each toxin was dissolved in sesame oil and injected into the sciatic nerve of rats. The nerves were subsequently examined by teasing and as sections by light and electron microscopy. During the first 3–4 days after injection, oil droplets, probably containing toxin, were observed in the cytoplasm of Schwann cells with intact myelin sheaths. Clinical signs of weakness in the limb first appeared at 5–6 days and were accompanied by segmental demyelination mainly of the larger fibres. These observations suggest that the toxins have a primary action on Schwann cell metabolism. The results of local injection of purified toxins are discussed in relation to reports of nerve damage in animals following oral administration of the endocarp where intramyelin vacuole formation and segmental demyelination are prominent features.     

Double Atrial Responses to a Single Ventricular Impulse in Long RP' Tachycardia

Double atrial responses (DARs) to a single ventricular impulse have been described in patients with long RP' tachycardia. To define the determinants for the occurrence of DARs. 8 cases with long RP' tachycardia were examined. The mechanism of long RP' tachycardia was the orthodromic atrioventricular reciprocating tachycardia (AVRT) involving a slow conducting concealed accessory pathway in 4 cases and uncommon (fast-slow) type of atrioventricular nodal reentrant tachycardia (AVNRT) in the other 4 cases. Programmed and rapid ventricular pacing was performed during sinus rhythm and also rapid ventricular pacing during tachycardia (i.e., entrainment). The retrograde effective refractory period (ERP) and the retrograde maximal 1:1 conduction rate of the fast and slow conducting pathways were examined. In 1 of the 4 cases with AVRT, DARs were observed during programmed and rapid ventricular pacing, performed during sinus rhythm and also during entrainment. In 1 of the 4 cases with AVNRT, DARs were observed only during entrainment. The determinants of DARs in cases with long RP' tachycardia were: (1) presence of two different retrogradely conducting pathways; (2) short ERP of the retrograde fast and slow conducting pathways and a short minimal pacing cycle length at which 1:1 ventriculoatrial conduction occurs via these pathways; (3) crucial conduction delay in the slow conducting pathway: and (4) preexisting antegrade unidirectional block in the slow conducting pathway or the antegrade block in the slow conducting pathway produced by collision with a previous retrograde impulse during entrainment.