Amacrine cells,bipolar cells and ganglion cells of the cat retina: A Golgi study

Neuronal types contributing to the inner plexiform layer of the cat retina are described based primarily on light microscopy of Golgi-impregnated retinal whole-mounts. Cells have been characterized on morphological criteria that include dendritic branching patterns, dendritic tree sizes, cell body sizes and stratification of processes in the inner plexiform layer. Nine different types of bipolar cell, 22 different types of amacrine cell and 23 different types of ganglion cell can be distinguished using one or more of these morphological criteria. The significance of the different morphological types of cells is discussed, particularly in relationship to the functional bisublamination of the cat inner plexiform layer.     

Evaluation of studies of the relationship between blood lead and air lead

Summary An evaluation of the major studies of the effects of airborne lead on blood lead levels of male and female adult and child populations is presented. Analysis of these studies shows that the blood lead-air lead slope for adults is approximately 1.0 for both men and women. This implies that an exposure to an additional 1 g Pb/m³ of air can result in an increase of approximately 1 g Pb/100 ml of blood. The precision of the slope for adults is rarely better than ±0.5 to ±0.7 and can be as large as ±1.0. A large portion of this uncertainty in the calculated slope is due to blood lead measurement error. The slope of the blood lead-air lead response for children ranges from 0.7 to 1.4 and is approximately the same as that for adults. The accuracy of this number is less clear for children than adults due to the small data base. Many of the studies of children have been on populations living in the vicinity of smelters. It is questioned whether these data are representative of the air lead exposure of children living in urban and suburban communities.     

Motor effects following application of putative excitatory amino acid antagonists to the region of the mesencephalic dopamine cell bodies in the rat

Summary The excitatory amino acid antagonists 2-amino-5-phosphonovalerate and -D-glutamylglycine have been applied focally to the ventral tegmental area and both the pars compacta and pars reticulata of the substantia nigra of the rat. The injections were performed under halothane anaesthesia so that behavioural effects could be observed 5 min afterwards. Bilateral application of either antagonist to the ventral tegmental area and the pars compacta of the substantia nigra induced enhanced locomotor activity in an open field. This effect was blocked by pretreatment of the animals with a low dose of the dopamine receptor antagonist fluphenazine. Bilateral application of either antagonist to the pars reticulata of the substantia nigra produced sedation and a reduction in locomotor activity. Unilateral injection of either of the excitatory amino acid antagonists into the pars reticulata or pars compacta of the substantia nigra both resulted in contraversive circling behaviour The effect of intranigral (both pars compacta and reticulata) 2-APV and -DGG was accompanied by a significant increase in concentrations of both 3,4-dihydroxyphenylacetic acid (to 158–160% of control following injection into pars compacta, and 134–146% of control injected into pars reticulata) and homovanillic acid (to 161–166% of control following injection into pars compacta, and 186–210% of control injected into pars reticulata) in the ipsilateral, striatum. Pretreatment of these animals with fluphenazine (0.3 mg/kg) antagonized this circling behaviour.These results indicate that antagonism, of excitatory amino acid receptors in the region of the midbrain of the rat leads to specific behavioural effects, which may in part be mediated through the ascending dopaminergic projections.Abbreviations used 2-APV 2-amino-5-phosphonovaleric acid - -DGG -D-glutamylglycine - SN substantia nigra - VTA ventral tegmental area - HVA homovanillic acid - DOPAC 3,4-dihydroxyphenylacetic acid A preliminary communication of this work was presented to the British Pharmacological Society in Bradford, April 1981     

Dynamics of formation and resolution of vasogenic brain Oedema

Summary Six patients with recently ruptured intracranial aneurysms were treated preoperatively with tranexamic acid (AMCA). Two patients received 6 g daily in i.v. infusion, two had 6 g daily by i.v. injection, and two patients were given AMCA 9 g daily by mouth during the first week after bleeding. Serial assays of AMCA and fibrin/fibrinogen degradation products (FDP) in cerebrospinal fluid (CSF) were performed during 6–13 days after the initial subarachnoid haemorrhage (SAH). Judged from the decline in CSF-FDP, an assumed therapeutic level of 1 mg/l of AMCA in CSF was reached within 24–36 hours after the first dose when the drug was administered intravenously and within 48 hours when the drug was given orally.     

Giant axonal neuropathy. Report of a case with normal hair.

A further case of giant axonal neuropathy is described. The diagnosis was made by sural nerve biopsy in a boy presenting signs of a progressive spinocerebellar syndrome with polyneuropathy. Ultrastructurally a severe abnormality of this peripheral nerve, with loss of thick myelinated nerve fibers and the presence of giant axonal swellings was evident. The axonal swellings appeared to be caused by an accumulation of filaments which were also present in Schwann cells, as well as in endothelial and perineurial cells, justifying the term of "generalized microfibrillar hyperplasia". It is most remarkable that the patient's hair was not unusual, in contrast to the previously reported cases who had "kinky hair".     

Biochemical investigations into the alcoholic delirium: Alterations of biogenic amines

Summary In eight male patients with alcoholic delirium concentrations of 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovannilic acid (HVA) in CSF, activity of dopamine--hydroxylase (DBH), and urinary excretion of noradrenaline (NA), adrenaline (A), and dopamine (DA) were measured during the delirium and a drug-free control period.MHPG concentration in CSF, excretion of NA and A as well as activity of serum DBH were significantly elevated during the delirium phase as compared to the control period. Urinary DA excretion and HVA in CSF did not show any constant changes. There was a positive correlation (r=0.64) between DBH activity and the intensity of the delirium (as measured on the delirium rating scale).It is hypothesized that there is a relationship between alcoholic delirium and increased central noradrenergic activity.Parts of this study were presented at the Sixth International Institute on the Prevention and treatment of Drug Dependence (Hamburg, June 28–July 2, 1976)     

Effect of occupational mercury exposure on plasma lysosomal hydrolases

Summary The activities of three plasma lysosomal hydrolases, -galactosidase, -glucuronidase and -N-acetylglucosaminidase, were studied in 20 workers exposed to metallic mercury vapor in a chlorine alkali plant and in 10 nonexposed referents. The urinary excretion and blood levels of mercury were determined on the day of study, and the history of mercury exposure was reviewed from the records of mercury concentrations in urine and blood over periods of up to 133 months. The average levels of -N-acetylglucosaminidase and -glucuronidase were higher in the plasma of exposed workers, but the difference was not significant. No significant positive correlation was seen between lyosomal enzyme activities and cumulative long-term exposure to mercury. It is concluded that measurement of plasma lysosomal hydrolase-activities is not of great value in the biological monitoring of workers exposed to low concentrations of metallic mercury vapor.In line with published data, the concentration of mercury showed a clearcut diurnal variation in nonexposed persons, persons currently exposed and persons with a history of past exposure. The excretion rate of mercury remained constant throughout the day.     

Exercise and heart disease. Epidemiology of the "exercise hypothesis"

The "exercise hypothesis" states that exercise protects against coronary heart disease. Reviewed herein is the epidemiologic evidence for and against the "exercise hypothesis." The weight of evidence supports the view that exercisers have a lower risk of coronary disease, but that vigorous exercise cannot always prevent progression of coronary atherosclerosis and does increase the risk of sudden death in persons with advanced coronary atherosclerosis. It is concluded that the "exercise hypothesis" is plausible, even likely, but still unproved.     

Acute lung response to amosite asbestos: a morphological study

The acute morphological response to amosite asbestos in the guinea pig was studied by light microscopy and by transmission, scanning, and scanning transmission electron microscopy. Fiber identification was carried out by energy dispersive X-ray analysis. Animals were studied at postinjection intervals of 2, 4, and 12 hr and 1-7 days. Three groups of test animals were studied for each time interval. These consisted of a vascularly perfused parenchymal group and a free cell lavaged group. The information obtained was compared with saline-injected and normal control animals. The acute tissue response was characterized by intraalveolar, not interstitial, events. The early phagocytic response was shared between polymorphs and macrophages, while in the longer intervals, the macrophages were the phagocytic cell type. Packaging differences within the two types of phagocytes were seen. Endothelial stability was noted, while some edematous type I pneumocytes were observed. Fibrotic involvement was limited to some intraalveolar fibrin deposits. It is suggested that the term "free asbestos fibers" refers to an extracellular event, while intracellular fibers are coated with either a membranous sheath, a siderosome, or a classical ferruginous coating.