A two-site monoclonal antibody ELISA for the quantification of the major Dermatophagoides spp. allergens, Der p I and Der f I

A two-site monoclonal antibody (Mab) ELISA was developed to measure the Group I allergens from Dermatophagoides spp., Der p I from D. pteronyssinus and Der f I from D. farinae. Species-specific Mabs were used to coat microtiter plates which were then incubated with allergen or house dust extracts. Bound allergen was detected using a biotinylated Mab which recognized a common epitope on both Der p I and Der f I, followed by the addition of streptavidin-peroxidase and ABTS/H2O2 substrate. The assay had low non-specific binding (approximately 0.08 absorbance units) and had a sensitivity of 5 ng/nl for aqueous allergen extracts (equivalent to 0.1 microgram allergen/g dust). 53 dust samples were assayed using the Mab ELISA and an RIA previously described using 125I-labelled Mab. The results showed a very good quantitative correlation between the assays (r = 0.96, p less than 0.001 for Der p I; r = 0.92, P less than 0.001 for Der f I). A further 132 dust samples from a different geographical areas were also assayed by both methods and gave correlation coefficients of 0.90 (P less than 0.001) and 0.86 (P less than 0.001) for Der p I and Der f I, respectively. The Mab ELISA will be useful in epidemiological studies of allergic asthma, both in the assessment of levels of dust mite allergen present in houses and the efficacy of allergen avoidance regimes.

The retinohypothalamic tract in the cat: retinal ganglion cell morphology and pattern of projection

The pattern of retinal projection to the hypothalamus and the morphological properties of the retinal ganglion cells that comprise the retinohypothalamic tract have been examined in the cat. Intraocular injections of horseradish peroxidase revealed a dense retinal projection to the ventral suprachiasmatic nucleus; however, lighter projections were seen in the dorsal suprachiasmatic nucleus, and in hypothalamic regions both dorsal and lateral to the suprachiasmatic nucleus. Intrasuprachiasmatic nucleus injections of horseradish peroxidase retrogradely labelled retinal ganglion cells that were small to medium in soma size. The labelled ganglion cells exhibited long thin dendrites that were sparsely branched. The labelled retinal ganglion cells exhibited a significant change in soma size associated with retinal eccentricity. The morphological characteristics of the ganglion cells that project to the suprachiasmatic nucleus are similar to those of gamma cells.

Synovial cyst at the craniovertebral junction

A case of synovial cyst of the upper cervical spine that resulted in spastic quadriparesis and sensory loss is reported. Radiographic evaluation included a computed tomography scan after myelography and a magnetic resonance imaging scan. The synovial cyst was removed by a laminectomy at C-1 and C-2, combined with a foramen magnum craniectomy. The patient had a good recovery.

Effects of microgravity on brain neurotransmitter receptors

Neurotransmitter receptor binding and Na+, K+-ATPase activity were examined in the brains of six rats exposed to 7 days of microgravity during the flight of Spacelab 3. The same variables were examined in a group of six ground control rats. 5-HT1 receptor number in the hippocampus was significantly elevated by exposure to the microgravity environment, and cortical sodium-potassium pump activity was significantly depressed. A marginal depression in dopamine D-2 binding in the striatum was noted. Dopamine and 5-HT binding in a wide variety of other central regions, in addition to GABAA, muscarinic acetylcholine, adenosine A1, and opiate receptor binding, and adrenoceptor binding, was unaffected by microgravity exposure.

Hypothermia and severe head injury

Two patients who were deeply unconscious (GCS = 4) following head injuries, sustained whilst intoxicated with alcohol, became hypothermic due to cold exposure. Despite negative prognostic factors both underwent craniotomy and evacuation of large acute subdural haematoma. After intensive postoperative management and rehabilitation both have made satisfactory recoveries. The contribution of hypothermia to their unpredicted favourable outcome is discussed, and the importance of recording temperature in head-injured patients is emphasized.

Cardiovascular effects of fentanyl reversal by naloxone at varying arterial carbon dioxide tensions in dogs

Clinical reports, as well as animal studies, have described cardiovascular and sympathetic stimulation after the administration of naloxone (NX) to reverse opioid-induced respiratory depression. This investigation examines the effect of PaCO2 on hemodynamic and adrenergic responses to NX, by means of 24 experiments carried out in six dogs. Each dog underwent NX reversal of fentanyl (FEN) at three different PaCO2 levels: 20, 35, and 60 mm Hg. In a final series of six experiments, the dogs were exposed to increasing PaCO2 after autonomic block by total spinal anesthesia and vagotomy. During enflurane anesthesia, 50 micrograms/kg FEN decreased mean arterial blood pressure (MAP), heart rate (HR), and plasma concentrations of norepinephrine (NE) and epinephrine (EPI) significantly. NX 0.4 mg promptly returned HR and MAP to baseline or above in all experiments; catecholamine (CA) levels increased only in hypercapnic dogs. Increases in HR were the same in all series. MAP, EPI, and NE levels were significantly greater than pre-FEN baseline values only in hypercapnic dogs 1 minute after NX and were also significantly higher in hypercapnic than in hypocapnic dogs at this time. NE levels were greater in hypercapnic dogs at all time periods after NX. In blocked dogs, neither F nor NX had any effects on hemodynamic functions or plasma CA levels; the institution of hypercapnia caused significant decreases in HR, MAP, and systemic vascular resistance. This direct circulatory depressant action of an elevated PCO2 may have attenuated the indirectly mediated excitatory hemodynamic effects of NX in intact dogs, thus explaining the relatively greater effect of hypercapnia on adrenergic than on hemodynamic responses to reversal.(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated cerebellar glucose metabolism in microvascular white matter disease: normal aging and Alzheimer's disease

Young normal, elderly, and clinically diagnosed Alzheimer disease subjects who had undergone positron emission tomography (PET) and computed tomography (CT) examinations were studied to determine the effect of periventricular white matter lesions on cerebellar glucose metabolic rates. PET-determined cerebellar metabolic rates were elevated in subjects with periventricular white matter lesions. These results suggest the cautious use of cortical-to-cerebellar ratios in future PET or single-photon-emission CT (SPECT) studies.

Transfusion therapy in emergency medicine

Volume replacement is critical to the resuscitation of the hemorrhaging patient, but this usually can be accomplished quickly and safely with crystalloid and/or colloid solutions. Red cells should be used in addition to asanguinous fluids in the treatment of tissue hypoxia due to anemia. The need for whole blood as opposed to packed red blood cells is controversial. However, plasma should not be used as a volume expander, and its use to supplement coagulation factors during the massive transfusion of red cells should be guided by laboratory tests that document a coagulopathy. Similarly, platelet transfusions are indicated to correct documented thrombocytopenia or platelet dysfunction, and routine prophylaxis after fixed volumes of red cells results is unwarranted. Many anticipated complications of massive transfusions, including hemostatic abnormalities, acid-base imbalances, hyperkalemia, and hypocalcemia, are uncommon or of limited clinical significance. The risks of immune hemolysis and transfusion-transmitted diseases, on the other hand, are significant, and argue for judicious use of blood components. In emergencies in which blood is required immediately before compatibility testing can be completed, O-negative uncrossmatched blood can be requested. Careful blood specimen collection and patient identification prior to transfusion are critical. Practices that emphasize blood conservation, including the use of autologous salvaged blood, are always to the patient's advantage.

Gas gangrene occurring soon after compound depressed skull fracture

Two cases of Clostridium perfringens infection occurring less than 24 hours after compound depressed skull fracture are reported. The infection was principally intracranial in the first and extracranial in the second; both required surgical debridement and antibiotic treatment. Attention is drawn to the rapidity with which a potentially life-threatening infection can develop in civilian head injury and to the implications for acute management of patients with compound depressed fractures.

Information explosion in radiology

We studied the increase in the number of articles in the radiologic literature in the years 1970, 1978, and 1985 using the Medlars program which provides reproducibility, a recognized bibliographic pool, and a wide coverage of the medical literature. A dramatic increase in the number of articles was found; the increase has both positive and negative implications for the profession. A similar analysis of monographs using the Catline file and the same subject headings also showed a significant increase in the volume of material relating to certain radiologic subspecialties. The problems arising from the attempt to identify and extract relevant information from this overwhelming mass of radiological data should be addressed.

Pharmacokinetic fate of 14C-labeled deoxynivalenol in swine

The pharmacokinetics of the trichothecene mycotoxin deoxynivalenol (DON) was investigated in swine following intravenous (0.30 mg, 0.35 microCi/kg) and intragastric (0.60 mg, 0.60 microCi/kg) administration of the 14C-labeled toxin. After iv dosing, plasma concentration data favored a three-compartment open model with half-life values for the rapid distribution (alpha), slower distribution (beta), and terminal elimination (gamma) phases of 5.8, 96.7, and 510.0 min, respectively. The apparent volume of distribution (V'd) was 1.34 liter/kg, the volume of the central compartment (Vc) was 0.166 liter/kg, and the plasma clearance was 1.81 ml/min/kg. DON was rapidly cleared essentially unchanged (greater than 95%), and was excreted primarily in urine (86-104%), with minor elimination in bile (3-5%). Following intragastric dosing DON was very rapidly absorbed, reaching near peak plasma levels within 15-30 min. Levels remained elevated (63-325 ng/ml) for approximately 9 hr, and began declining slowly (t1/2 beta = 7.1 hr) thereafter. The calculated systemic bioavailability (F) was between 48 and 65%, although urinary and biliary recoveries indicated marginally greater absorption actually occurred (54-85%). Overall, although DON was eliminated rapidly and completely within 24 hr following a single iv or intragastric dose, data suggest that residues may undergo temporary sequestration in a tissue depot.

Positron emission tomography with the deoxyglucose technique and the diagnosis of Alzheimer's disease

Riege and Metter provide a useful review of the application of PET in the evaluation of Alzheimer's disease (AD). We share their enthusiasm for continued support and development of tools to image metabolic processes. Our commentary focuses on neuroimaging and the diagnosis of AD and introduces some new data that directly impacts on the interpretation of PET-2-deoxyglucose (2DG) data.

Epidermal growth factor binding in intracranial neoplasms: preliminary biochemical and clinicopathological findings

The binding capacity for epidermal growth factor (EGF) was determined in 34 intracranial neoplasms (14 glioblastoma, seven low-grade gliomas, six meningiomas, and seven others) and four specimens of normal brain by using [I125]EGF. EGF binding and binding affinity of the sites in the tumour and brain samples were compared to placenta and rat liver. All specimens of normal brain were negative. Ten of 14 glioblastoma specimens contained EGF binding (level range 10-39,660 fmol/mg protein), however, ligand binding affinity was high in only three tumours. Only one of nine low-grade gliomas contained EGF binding activity. Five of six meningiomas contained EGF binding sites (level range 49-776 fmol/mg protein) and binding affinity was high in two. When present EGF binding activity was found in all cellular fractions except the cytosol. There were no clinical or histopathological features within major tumour groups that were predictive of either high or specific EGF binding activity. These preliminary studies have confirmed that EGF receptor-like activity is present in the particulate fractions of intracranial neoplasms of both mesenchymal and neuroctodermal origin. In a large proportion of these tumours the EGF binding affinity is low, suggesting either a less specific or truncated EGF binding site.

Longitudinal CT study of parenchymal brain changes in glioma survivors

We reviewed the serial CT studies obtained between 1974 and 1986 of 31 patients with malignant glioma who survived for 2 to 11 years after surgical removal of their tumors. In all cases surgery was followed by radiation therapy to the head (6000 rad) and chemotherapy. Patients were divided into two age groups: those under age 40 (n = 13) and those over age 40 (n = 18). By 2 years all patients in the older group developed evidence of leukoencephalopathy characterized by periventricular zones of decreased attenuation. Only 58% of the younger group showed evidence of white matter changes at this point. All patients from both age groups who survived for 4 years developed leukoencephalopathy. The severity of leukoencephalopathy from 6 months after surgery and beyond was always greater in the older group. All patients developed cerebral atrophy as evidenced by sulcal dilatation and ventricular enlargement. Atrophy was progressive beginning with the first postirradiation scan, and was always more severe in the older patients. A significant difference was found in the clinical status of the two age groups as determined by the mental status score and the Karnofsky scale. Despite progressive brain changes, survivors under age 40 maintained a nearly normal mental status and Karnofsky scores until their death, whereas survivors over age 40 showed progressive clinical decline.

Reactions of patients with focal cerebral lesions to success or failure

Multiple measures were used to investigate emotional reactions to card sorting in patients with focal cerebral lesions and in matched non-brain-injured controls. Spontaneous facial expressions of patients with anterior lesions were impoverished, relative to the posterior group, on a quantitative index of facial movement. This deficit did not appear to be attributable to group differences on lesion variables, or degree of cognitive deficit. There were also indications that a "non-emotional" facial-motor deficit was not the primary cause. The marked anterior deficit for facial movement was not, however, associated with equally pronounced deficits on qualitative, self-report and heart rate indices of emotional response. Right hemisphere patients differed from left hemisphere patients on only one qualitative measure of emotional reaction, but this may have been due to the stronger negative reactions of dysphasic patients. Left unilateral neglect was not associated with reduced emotional response.

Response to heavy nitrogen applications in fertilizer experiments in British forests

Increasing concern over the level of nitrogen inputs to forests in polluted rain has led to a number of suggestions of possible adverse consequences under the general heading of nitrogen saturation. A saturated ecosystem may be one (a) in which the trees show no growth response to the addition of further nitrogen, (b) in which addition of further nitrogen leads to growth disturbances or reduction, or (c) in which elevated nitrogen inputs lead to increased losses of nitrate in streamwater. Experience gained from forest fertilizer experiments is used to examine each of these suggestions. A definition involving a lack of growth response (a) is shown to be based on a lack of understanding of the continuing changing patterns of nitrogen demand and mineralization in even-aged forests. Similarly, using growth disturbances (b) is unsatisfactory because, it is suggested, these are either secondary deficiencies that appear once growth accelerates with added nitrogen or are a consequence of changing growth with increasing size. A definition based on increased loss of nitrate is, by analogy with the situation for sulphate, at least superficially attractive. However, the fact that nitrate retention is predominantly biological, rather than chemical, makes for difficulties and the limited evidence available suggests that many exceptions and variations may exist. Whilst experience with forest fertilizers might not be entirely apposite, for example foliar uptake from polluted rain may be a factor, it is urged that at least any hypothesis put forward should be compatible with information gained from fertilizer trials.

Other potential clinical uses of oral rehydration

An increasing awareness that bowel absorptive function can be maintained or returned to normal soon after trauma or abdominal injury and the formulation of glucose/electrolyte solutions specifically designed to be rapidly absorbed from the small bowel are responsible for the current trend of early oral rehydration and decreasing use of intravenous fluids in surgical patients. Much of this article is devoted to observations and results of clinical trials on surgical patients in Aberdeen Royal Infirmary and Dr Gray's Hospital, Elgin. To date, the results of early oral rehydration after surgery have been sufficiently encouraging to create changes in the routine fluid resuscitation and management protocols in several areas of surgical practice at these centres.

Multicentric glioma presenting with hemorrhage

We report a case of multicentric malignant astrocytoma occurring simultaneously in both cerebrum and cerebellum, presenting with hemorrhage into the cerebellar tumor. Hemorrhage into a cerebellar glioma in an adult is very rare. None of the cases of multicentric glioma described in the literature presented with intratumoral hemorrhage. This combination in our patient has prompted us to report this case and to reaffirm the need to consider the diagnosis of malignant glioma in patients with multiple intracranial tumors.

Head injury rehabilitation: 4 years' experience in Edinburgh

A survey was done of all cases of head injury admitted to a neurorehabilitation unit which, while mainly servicing the regional acute head injury unit, receives patients from throughout Scotland. During the 4 calendar years 1983-1986, 183 new cases of head injury were treated. The patients were predominantly young adult males the great majority of whom had suffered severe head injuries. Most were directly transferred from neurosurgical units within 6 months of injury. The length of stay in the unit varied from less than 1 month for half of the patients to as long as 10 months. Eighty-four per cent of patients were discharged home. The limitations and constraints upon the service are described and the need for a rational approach to the development of head injury rehabilitation facilities in the United Kingdom are discussed.

A new look at uterine muscle contraction

Recent progress in our understanding of uterine smooth muscle contraction is reviewed. We no longer believe that actin-myosin interaction in the myometrium occurs through activation of the thin filament; but it is triggered by calcium-dependent phosphorylation of myosin in the thick filament. Calcium is now thought to originate from both extracellular and intracellular sources. Calcium can enter the cell through either a voltage- or a hormone-controlled calcium channel. The intracellular source of calcium is the sarcoplasmic reticulum. The effect of oxytocin in human labor is no longer considered the result of increased circulating oxytocin but rather of increased oxytocin receptors. In contrast, the contractile action of some prostaglandins is related to increased prostaglandin formation at human parturition. The step between hormone binding and cellular action is mediated by second messengers. The uterine-relaxing action of cyclic adenosine monophosphate is now thought to be limited to the inhibition of myosin phosphorylation. Recently discovered second messengers for contraction of the myometrium are phosphoinositides; their turnover causes calcium release from the sarcoplasmic reticulum. Guanine nucleotides are thought to be modulators of these two second messengers.

The anti-emetic properties of 1-sulpiride in a ground-based model of space motion sickness

L-sulpiride, at a dose of 4 mg/kg, essentially abolished motion-induced emesis in a group of 6 squirrel monkeys undergoing horizontal rotation at 25 rpm, a terrestrial model of space motion sickness (SMS). Extrapyramidal side effects were not observed. In the absence of the drug, the usual emetic response returned. In comparison while typical neuroleptics were also strongly anti-emetic, they produced a considerable degree of rigidity and akinesia.