Altered neuronal sensitivity of lateral geniculate neurones to noradrenaline and 5-HT following exposure to continuous lighting

Rats were housed in either continuous lighting (LL), an extended photoperiod of 18 h light-6 h dark (LD 18:6) or a 12 h light-12 h dark (LD 12:12) lighting cycle. The effects of these various lighting regimens on the sensitivity of dorsal lateral geniculate neurones to iontophoresed noradrenaline and serotonin (5-HT) was examined. Exposure to either continuous lighting or to an extended photoperiod (LD 18:6) resulted in the development of an enhanced responsiveness to iontophoresed noradrenaline (alpha 1-adrenoceptor) and 5-HT. The development of light-induced noradrenaline and 5-HT supersensitivity resembles the changes obtained with antidepressant treatments.

Studies on the mechanism of histamine-induced release of noradrenaline and 5-hydroxytryptamine from slices of rat cerebral cortex

The effect of histamine on the release of endogenous noradrenaline and 5-hydroxytryptamine (5-HT) has been examined in slices of rat cerebral cortex. Histamine was found to produce a marked release of both amines from rat cerebral cortex at concentrations between 0.1 and 1 mM. This response to histamine was relatively resistant to removal of calcium ions from the incubation medium when compared to the release evoked by depolarising potassium stimuli. The response to 1 mM histamine was not, however, significantly inhibited by the H1-antagonist mepyramine (1 microM) or the H2-antagonist cimetidine (100 microM). Furthermore, impromidine which is both a potent H2-agonist and a potent H3-antagonist was without effect on the basal and histamine-stimulated release of endogenous noradrenaline and 5-HT. The response to histamine was, however, significantly attenuated by nisoxetine, fluoxetine and imipramine which are inhibitors of the amine uptake systems. The results of this study show that high concentrations (0.1 to 1 mM) of histamine can produce a marked increase in the release of endogenous 5-HT and noradrenaline from rat cerebral cortex, apparently via a non-receptor mechanism. This effect will need to be borne in mind in interpreting biochemical and behavioral responses to histamine in this concentration range.

Sequential endoscopy and biopsy of intact rat stomach. A new simple technique

This paper describes the technique of sequential endoscopy and biopsy of the intact rat stomach. It is recommended that this procedure be performed on fasted animals with access to water only, when a mortality of only 4% can be achieved.

Class II molecules on rat alveolar type II epithelial cells

Class II (Ia) molecules of the major histocompatibility complex are important in the presentation of antigen to T cells and in the regulation of the immune response. Recent studies have suggested that many epithelial cell types can express class II molecules. We examined rat alveolar type II epithelial cells, a cell which can synthesize and secrete pulmonary surface-active material, for the expression of class II antigens. Using an indirect immunofluorescent technique with a mouse anti-rat class II monoclonal antibody (OX-4), the majority of type II cells isolated from pathogen-free Sprague-Dawley rats expressed Ia antigens as determined by fluorescent microscopy and cell sorter analysis. In culture, the Ia expression was lost from type II cells. The addition of recombinant interferon-gamma to cultures of type II cells induced the expression of class II antigens. These findings suggest that class II antigen expression on type II cells may have relevance to immune responses occurring in the lung.

Spectrum and mode of action of azithromycin (CP-62,993), a new 15-membered-ring macrolide with improved potency against gram-negative organisms

The macrolide antibiotic azithromycin (CP-62,993; 9-deoxo-9a-methyl-9a-aza-9a-homoerythromycin A; also designated XZ-450 [Pliva Pharmaceuticals, Zagreb, Yugoslavia]) showed a significant improvement in potency against gram-negative organisms compared with erythromycin while retaining the classic erythromycin spectrum. It was up to four times more potent than erythromycin against Haemophilus influenzae and Neisseria gonorrhoeae and twofold more potent against Branhamella catarrhalis, Campylobacter species, and Legionella species. It had activity similar to that of erythromycin against Chlamydia spp. Azithromycin was significantly more potent versus many genera of the family Enterobacteriaceae; its MIC for 90% of strains of Escherichia, Salmonella, Shigella, and Yersinia was less than or equal to 4 micrograms/ml, compared with 16 to 128 micrograms/ml for erythromycin. Azithromycin inhibited the majority of gram-positive organisms at less than or equal to 1 micrograms/ml. It displayed cross-resistance to erythromycin-resistant Staphylococcus and Streptococcus isolates. It had moderate activity against Bacteroides fragilis and was comparable to erythromycin against other anaerobic species. Azithromycin also demonstrated improved bactericidal activity in comparison with erythromycin. The mechanism of action of azithromycin was similar to that of erythromycin since azithromycin competed effectively for [14C]erythromycin ribosomebinding sites.

Electrophysiological responses of hamster suprachiasmatic neurones to neuropeptide Y in the hypothalamic slice preparation

The rate and pattern of neuronal discharge in the hamster suprachiasmatic nucleus (SCN) was studied using an in vitro hypothalamic slice preparation. The firing rate of hamster SCN neurones (n = 183 cells) exhibited a circadian variation similar to that reported in the rat. SCN neurones tested for responses to pressure ejection of neuropeptide Y (NPY) (n = 49) were either tonically excited (65%) or unresponsive (35%). There was a tendency for more NPY-responsive cells to be recorded during the light phase of the circadian light-dark cycle.

Isapirone is a partial agonist at 5-hydroxytryptamine 1A (5-HT1A) receptors in the rat hippocampus: electrophysiological evidence

Using iontophoretic techniques we observed that in vivo isapirone (TVX Q 7821), a selective ligand for the 5-HT1A binding site, at low ejection currents (5-30 nA) antagonised 5-HT and 8-hydroxy-2-(di-n-propylamino) tetralin (DPAT)-induced suppression of hippocampal unit activity, with little effect on baseline firing rate itself. At higher ejection currents (20-100 nA) or following prolonged application, isapirone inhibited unit firing. Responses to GABA were unaffected by isapirone. These data demonstrate that isapirone is a 5-HT1A receptor antagonist with partial agonist properties on 5-HT sensitive neurones in the rat hippocampus.

Circadian variation in sensitivity of suprachiasmatic and lateral geniculate neurones to 5-hydroxytryptamine in the rat

Extracellular single-unit recordings were obtained from neurones in the suprachiasmatic nuclei (s.c.n.) of the rat (a putative circadian pace-maker), the ventral lateral geniculate nucleus (v.l.g.n.) and the hippocampus. These areas receive a 5-hydroxytryptamine (5-HT) innervation from the raphe nuclei. Recording of neuronal activity in the s.c.n., v.l.g.n. and the hippocampus revealed a diurnal variation in the response to the ionophoresis of 5-HT. This variation was manifest as a 2-3-fold increase in post-synaptic sensitivity to 5-HT during the subjective dark (active) phase of the circadian cycle. In contrast there was no apparent circadian variation in the sensitivity of s.c.n., v.l.g.n. or hippocampal neurones to ionophoresed gamma-aminobutyric acid (GABA). Neuronal activity recorded in the s.c.n., v.l.g.n. and hippocampus also exhibited a circadian variation in the recovery from 5-HT-induced suppression of firing. This may reflect reuptake processes as recovery can be prolonged by ionophoresis of uptake blockers (imipramine or fluoxetine). Rats (n = 15) expressing circadian arrhythmicity in their rest-activity behaviour induced by long-term continuous illumination (150-200 lx) showed no apparent circadian variation in 5-HT sensitivity. This loss was accompanied by either the development of a 5-6-fold subsensitivity to ionophoresed 5-HT (eleven out of fifteen rats) or a 2-3-fold supersensitivity to ionophoresed 5-HT (four out of fifteen rats). A similar loss of circadian variation and the development of a subsensitivity to ionophoresed 5-HT was also found in three rats sustaining complete electrolytic lesions of the s.c.n. These changes were not found in rats (n = 4) with partial s.c.n. lesions. These results implicate the s.c.n., or fibres passing through it, in the circadian modulation of 5-HT sensitivity in neurones both intrinsic to the s.c.n. circadian pace-maker itself and in the hippocampus and lateral geniculate nucleus (regions remote from the s.c.n.).

Time course of the binding of platinum to subfractions of the kidney cytosol in the cisplatin-treated rat

In male rats treated with cis-dichlorodiammine platinum II (cisplatin, 5 mg/kg, s.c.), the accumulation of Pt in the kidneys occurred in two phases. Total renal Pt content peaked after 15 min and decreased rapidly, then increased to a second peak after 48 hr and thereafter decreased slowly during the next 6 days. Sephadex G-50 chromatography showed that in the kidney cytosol Pt was located in three subfractions; a high molecular weight (HMW) fraction (relative elution volume, Vr = 0.9-1.2), a heterogeneous low molecular weight (LMW) Pt-binding fraction (Vr = 1.2-2.2) and a LMW complex fraction (Vr = 2.2-2.7). Initially, most of the Pt was located in the HMW- and LMW complex fractions and the initial loss of Pt from the cytosol occurred from the latter fraction. In contrast, during the second phase much of the additional Pt accumulated in the LMW Pt-binding fraction, the Pt content of which paralleled that in the whole kidney. It is suggested that the LMW Pt-binding fraction may play a significant role in the accumulation and retention of Pt and may provide a site of detoxification during the second phase of influx of Pt into the kidneys.

Erythrocyte morphology in women with severe preeclampsia and eclampsia. Preliminary observations with scanning electron microscopy

Scanning electron microscopy was used to study the morphologic characteristics of erythrocytes in women with preeclampsia and eclampsia. In nine nulliparous women with eclampsia, the proportion of abnormal red cells (schistocytes, echinocytes, and spherocytes) was significantly greater than in 12 normally pregnant control women (p less than 0.001). Likewise, the proportion of these abnormal erythrocyte forms was significantly greater in 12 nulliparous women with preeclampsia than in 25 normally pregnant control women (p = 0.009). Six women with mild pregnancy-induced hypertension without proteinuria were studied before and after magnesium sulfate therapy had been given, and no differences in the proportion of abnormal erythrocyte forms were found. Evidence for microangiopathic hemolysis, manifest by reticulocytosis and thrombocytopenia, was apparent with eclampsia, although only reticulocytosis was identified in women with preeclampsia. There was evidence for hepatic dysfunction in more than half of the women with eclampsia, and in nearly one third of those with preeclampsia. We speculate that compositional changes in the membrane, induced by plasma/erythrocyte lipid interchanges, which are predisposed by normal pregnancy and amplified by severe preeclampsia, especially in the presence of liver dysfunction, may have participated in the genesis of the red cell abnormalities observed. Furthermore, these abnormalities in the cell membrane may increase erythrocyte susceptibility to microangiopathic hemolysis.

Small male body size in garter snake depends on testes

In the red-sided garter snake (Thamnophis sirtalis parietalis) adult females are larger than adult males; this difference is apparent within 3 wk of birth, a time coinciding with high circulating levels of androgens. To study the ontogeny and regulation of this sexual dimorphism, male neonates were either castrated, castrated and given Silastic capsules containing testosterone or estradiol, or given a sham operation at 8, 9, or 10 wk of age. Female neonates were either given a Silastic capsule containing testosterone or dihydrotestosterone or given a sham operation at 8, 9, 10, or 14 wk of age. The sex difference in body size and growth rate in neonates was abolished by castration; the pattern of growth of castrated males was similar to sham-operated females. Androgens in the amounts administered failed to reverse the effects of castration, because castrated male and female neonates receiving exogenous androgens grew at the same rate as did sham-operated females. Males castrated as adults grow larger than adult males given a sham operation, indicating the inhibitory role of the testes on body size exists after sexual maturity. Treatment of adult males with testosterone, however, prevented the increase in body size after castration, suggesting that the mechanism regulating weight gain in the garter snake depends on gonadal androgen.

Development of gallstone pancreatitis. The role of the common channel

Whether bile reflux through a common channel into the pancreatic duct is a causative factor in the development of gallstone pancreatitis is controversial. To address this issue, we have reviewed a consecutive series of cholecystectomies performed with intraoperative cholangiograms. The cholangiograms and the patients' charts were reviewed independently to determine the incidence of a common channel in patients both with and without pancreatitis and to analyze their clinical courses. The group of patients who had pancreatitis showed a common channel in 19 (90%) of 20 cases, while those patients who did not have pancreatitis showed a common channel in 23 (35%) of 66 cases. The patients who had pancreatitis were less likely to have choledocholithiasis than were those patients who did not have pancreatitis, and these patients were less likely to require exploration of the common bile duct.

Interaction of platinum with metallothionein-like ligands in the rat kidney after administration of cis-dichlorodiammine platinum II

After the administration of the anticancer drug cis-dichlorodiammine platinum II (cisplatin) to male rats, the Pt in the soluble fraction of the kidney is isolated, by gel filtration, in association with a high molecular weight component and a low molecular weight fraction. At 24 h, Pt is also recovered in a metallothionein-like fraction which elutes from Sephadex G-50 with a lower apparent molecular weight than endogenous (Cu, Zn)-thionein or Cd-thionein isolated from the kidneys of Cd2+-treated rats. None of these low molecular weight metal-binding fractions binds to Octyl Sepharose CL-4B. On DE-52 ion exchange chromatography, Cd-thionein is resolved into two isometallothioneins whereas the low molecular weight Pt-binding fraction is only partially purified and contains at least six components which elute at higher gradient concentrations than metallothionein. Pretreatment with Cd2+ which stimulates the synthesis of renal and hepatic metallothionein has no effect on the uptake and subcellular distribution of Pt in the liver and kidneys. Cisplatin treatment reduces the concentration of Cu and Zn in the renal metallothionein and other soluble protein fractions in the kidney. When administered to Cd2+-pretreated rats, cisplatin promotes the loss of Zn from the soluble protein fractions but causes the redistribution of Cd from the metallothionein to the high molecular weight fraction and fails to inhibit the Cd2+-induced accumulation of Cu in the kidneys and the binding of Cu to the soluble protein fractions. It is suggested that metallothionein probably does not have a significant role in the renal metabolism of Pt following the administration of cisplatin to rats.

Hormonal independence of courtship behavior in the male garter snake

Garter snakes exhibit a dissociated reproductive tactic in which gonadal activity is minimal at the time of mating, increasing only after the breeding season has ended. Experiments are presented demonstrating that neither short-term nor longterm castration affects courtship behavior in adult male red-sided garter snakes (Thamnophis sirtalis parietalis). So long as males have passed through a low-temperature dormancy period (hibernation), castration either shortly after emergence in the spring, or before entering winter dormancy in the fall, does not prevent the display of intense courtship behavior on emergence. Similarly, males castrated during mating activity the previous spring prior to the annual testicular growth phase actively courted females on emergence from hibernation. Males adrenalectomized and castrated during low-temperature dormancy also courted females on emergence. Hypophysectomy during or before low-temperature dormancy did not prevent males from displaying high-intensity courtship behavior on emergence from hibernation. Treatment with sex steroid hormones, as well as hypothalamic and pituitary hormones, and a variety of neural and metabolic affectors also fails to elicit courtship behavior in noncourting males during the summer. It was concluded that causal mechanisms controlling courtship behavior in the red-sided garter snake are fundamentally different, at least at the physiological level, from those mechanisms described for many laboratory and domesticated species.

Pregnancy and sickle cell hemoglobinopathies: results with and without prophylactic transfusions

Maternal morbidity and perinatal outcome in 108 pregnancies complicated by sickle cell anemia (hemoglobin SS disease), sickle cell-hemoglobin C disease (hemoglobin SC disease), or sickle cell-beta-thalassemia disease were analyzed. Women given prophylactic red cell transfusions (1973-1982) during pregnancy were matched with historic controls whose care was almost identical except that blood was not given unless indicated (1955 to 1972). In women with hemoglobin SS disease who received prophylactic red cell transfusions, there was a sevenfold reduction in perinatal mortality and negligible maternal morbidity. In pregnancies complicated by hemoglobin SC disease during which transfusions were given, there were no perinatal losses, whereas there were in 18% of women not given transfusions. Maternal morbidity in women given transfusions was negligible; however, half of those not transfused experienced morbidity and, importantly, pulmonary complications were common. Transfusion-related complications included hepatitis and alloimmunization. From these experiences the authors conclude that prophylactic red cell transfusions reduce maternal morbidity and perinatal mortality appreciably, although perinatal morbidity is not eliminated. Transfusion therapy is justifiably started early in pregnancy for women with hemoglobin SS disease; however, transfusions may be withheld until the end of the second trimester for women with hemoglobin SC or sickle cell-beta-thalassemia disease.

Electrical and pharmacological properties of the suprachiasmatic nuclei

The suprachiasmatic nuclei (SCN) of the mammalian hypothalamus are in important circadian pacemaker. The electrical activity of these nuclei exhibits an intrinsic circadian rhythm. The rhythmicity of the SCN is also reflected in cyclic glucose consumption and serotonin metabolism. These rhythms are entrained to the light-dark cycle via the retinohypothalamic projection. This pathway, possibly together with a visual projection via the ventral lateral geniculate nuclei, innervates light-responsive SCN cells, which exhibit the functional properties of luminance detectors. The SCN contain various peptides, acetylcholine, and serotonin either intrinsically or in terminals of afferent projections. For acetylcholine it has been demonstrated that the SCN mediate the process of photic entrainment and light suppression of pineal synthetic activity. In the case of serotonin and vasopressin it seems certain that the SCN do not depend on their presence for generating circadian rhythms or for entrainment. Both substances may modulate the intrinsic pacemaker frequency through mechanisms that remain to be established.

Profound hypocalcaemia associated with oestrogen treatment of carcinoma of the prostate

A case of profound hypocalcaemia which occurred in a patient with osteoblastic metastatic carcinoma of the prostate after treatment with oestrogens is reported. Although there may have been other contributory factors, it was felt that the administration of oestrogens was the most important causative element. Treatment with high doses of oestrogens in patients with osteoblastic metastatic carcinoma of the prostate should be accompanied by frequent measurements of plasma calcium levels.

SV-40 virus-induced neoplastic transformation of hamster brain cells in vitro. Studies with scanning and transmission electron microscopy

Neoplastic transformation of one-day-old hamster brain cells was produced by infection with SV-40 virus and verified by phase contrast microscopy, growth in semisolid media, and intracranial tumor production after inoculation of the cells into other one-day-old hamsters. Transformed cells were studied by transmission and scanning electron microscopy. The numerous alterations in cell surface structure and in nuclear and cytoplasmic organization suggest a marked increase in cell metabolism and in the rate of mitosis and cell division. Cilia with a nine-to-zero pattern of microtubule doublets were present in cells with intermediate size filaments which stained for glial fibrillary acidic protein. The findings indicate that infection of one-day-old hamster brain cells in culture by SV-40 virus results in their transformation to a neoplastic state and the transformed cells are differentiating neoplastic astrocytes.

Rat cardiac muscle single cell automaticity responses to alpha- and beta-adrenergic agonists and antagonists

Isolated cardiac muscle cells from neonatal rat ventricular myocardium have both alpha- and beta-adrenergic, positive chronotropic responses, with sensitivity to applied adrenergic agents more than 100 times greater than the intact neonatal heart. These highly sensitive isolated single cells and small groups of cells also reveal partial agonist activity of the alpha-adrenergic antagonist, phentolamine, and the beta-adrenergic antagonist, propranolol. The most likely explanation for the high sensitivity is the lack of a desensitization process that could involve both a desensitization substance and changes in receptors. These experiments suggest that all adrenergic antagonists could possibly show partial agonist activity.

Isolated popliteal versus distal bypasses for limb salvage

The results of 54 bypass procedures--22 to an isolated popliteal segment and 32 to an infrapopliteal major calf vessel for limb salvage--were evaluated. After a distal bypass, the elevation of systolic pressure at the ankle was greater than that observed following a bypass to an isolated popliteal segment. However, healing times for ischemic lesions of the foot were comparable for each procedure. Patency and limb salvage rates for saphenous vein and polytetrafluoroethylene isolated popliteal segment bypasses were similar to those obtained with vein bypass grafts to infrapopliteal major calf vessels. In contrast, when polytetrafluoroethylene was used for a distal bypass below the popliteal artery, the failure rate was higher in the first year, with subsequent limb loss. These data suggest that, when a bypass operation is undertaken in the lower extremity for limb salvage, a bypass to an isolated popliteal segment, using either saphenous vein or polytetrafluoroethylene, is preferable to a polytetrafluoroethylene infrapopliteal bypass.

Metabolism of cadmium in the neonate: effect of hepatic zinc, copper and metallothionein concentrations on the uptake of cadmium in the rat liver

The accumulation and subcellular distribution of Cd2+ (1 mg/kg body wt, i.p.) in the liver of the neonatal rat is age-dependent. At 4 hr after treatment the liver Cd2+ contents in the 12-day-old, 20-day-old and adult rat are similar and greater than in the 2-day-old animal. The differences in hepatic Cd2+ concentration in the older age groups are consistent with the nonlinear weight gain of the liver in the developing animal. In the hepatic cytosol Cd2+ is incorporated into a high molecular weight and metallothionein fractions and transferred from the former to the latter. This process occurs less rapidly with increasing age. The uptake of Cd2+ by the whole liver and th hepatic metallothionein is not related to the total liver concentration of Zn2+ or copper and is not significantly influenced by the concentration of pre-existing metallothionein or the concentration of thionein-bound Zn2+ or copper. The results are discussed in relation to the possible effects of Cd2+ on the liver metabolism and tissue distribution of Zn2+ and copper in the developing animal.

Monoclonal antimacrophage antibodies: human pulmonary macrophages express HLA-DR (Ia-like) antigens in culture

Study of human macrophages and their role in disease has been hampered by lack of well-characterized tissue macrophages. We describe a simple procedure to obtain viable adherent cells in good yield from resected lung, characterize the cells as greater than 95% macrophage by standard criteria, and document expression of marker properties previously described in rodent macrophages. Human pulmonary macrophages were used to produce monoclonal antibodies and to study expression of HLA-A,B,C, HLA-DR, and related antigens. A new monoclonal mouse antibody, 18, showed restricted binding to macrophages from human lung or blood and to B lymphoid cells, but did not bind to closely related cells. With antibody 18 and other monoclonal antibodies of known specificity, DA2 and Genox 3.53, we showed that a remarkably high proportion of human pulmonary macrophages express HLA-DR framework and DC1 polymorphic determinants in culture. Although the macrophages differed in source and in their state of activation, single cell analysis revealed no heterogeneity in antigen expression.

Norepinephrine sensitivity and desensitization of cultured single vascular muscle cells

Isolated single vascular muscle cells were used for studies of the inherent norepinephrine sensitivity and the conditions important for detecting highest norepinephrine sensitivity. Rat vascular muscle cell contractions were quantitated from spontaneous contractions during pulse applications of the drugs, with a time course designed to simulate norepinephrine release in situ. Isolated vascular muscle cells showed a sensitivity to norepinephrine two orders of magnitude greater than those found from isolated intact blood vessels. Associated with the high sensitivity, there was a marked reduction in the response to a second application of norepinephrine or phenylephrine. The reduced second response appears to result from desensitization that is more pronounced in cells that have been exposed to only trace concentrations of catecholamines. These data appear to suggest that there might be continuous suppression of transmitter sensitivity that occurs as a result of transmitter exposure, and possibly cell-to-cell associations. Desensitization would at first severely limit the response to norepinephrine by reducing or eliminating the response to prolonged exposure or a second dose. Thereafter, a lessening of the desensitization process on continuous exposure to catecholamines would be the result, in part, of lowered sensitivity and, in part, of a smaller desensitization response. This process would continuously modulate norepinephrine sensitivity, based on the frequency and extent of stimulation, and we have called it the theory of physiological desensitization.

Noninvasive evaluation of venous function in chronic venous disease

Measurements of calf volume changes during treadmill ambulation were taken using mercury-in-Silastic (silicone rubber) strain gauges for noninvasive study of venous function in patients with chronic venous disease. Seventy-four limbs were evaluated: 24 with postphlebitic changes, 26 with superficial varicosities, and 24 normal. Calf volume changes as measured by mercury-in-Silastic strain-gauge plethysmography (MISSGP) during ambulation correlated well (r = 0.8) with simultaneously obtained direct venous pressure measurements. The refill time as measured by MISSGP also correlated with the pressure restoration time (r = 0.8). Patients with moderate-to-severe obstructive patterns as shown by contrast venography were found to decrease their calf volume with MISSGP significantly less (P less than 0.001) than did those patients with minimal or no obstruction of venous outflow as depicted by venography. MISSGP is shown to be a useful method of quantitatively evaluating the efficiency of the calf venous pump, the degree of reflux, and the severity of venous obstruction.

Cortico-recipient and tecto-recipient visual zones in the rat's lateral posterior (pulvinar) nucleus: an anatomical study

Afferents to the lateral posterior (pulvinar) nucleus in the rat were studied anatomically using retrograde tracing with fluorescent and horseradish peroxidase techniques. Layer V pyramidal cells in cortical areas 17 and 18a were found to project to the rostral portion of the lateral posterior nucleus (LTP) (the cortico-recipient zone). Cells in the deep superficial grey of the superior colliculus projected to the caudal portion of the LTP (the tecto-recipient zone), the posterior pole of which also received input from cortical area 36. These findings agree with the notion that the rat's LTP is functionally equivalent to regions of the feline and primate pulvinar-complex.

Differential responsiveness of cells in the visual zones of the cat's LP-pulvinar complex to visual stimuli

Multiple visual field representations are contained within the feline LP-pulvinar complex; regions differentiated by their afferent and efferent connectivity patterns as the striate-, tecto- and retino-recipient zones. Cell responses from these visuotopic zones were investigated in immobilized cats under N2O/O2 supplemented with pentobarbitone or Althesin, using spot, bar and textured stimuli. Response fields recorded within the LP-pulvinar complex were classified as diffuse, concentric, movement-, direction- or orientation-sensitive. Concentric receptive fields were further classified as sustained (X), transient (Y) or tonic/phasic W-cells. Direction- and movement-sensitive cells predominated in the striate- and tecto-recipient zones, respectively. Motion of noise fields, or noise bars against an identical stationary noise background elicited vigorous responses from cells in the striate zone, many showing a preference for noise stimuli. In contrast, cells from the tectal zone and other divisions of the LP-pulvinar complex were insensitive to noise. The retino-recipient zone at the lateral margin of the pulvinar nucleus was characterized by cells with concentric receptive fields, the majority exhibiting properties similar to W-cells in the LGNd. The evidence supports the notion of functional subdivision within the LP-pulvinar complex corresponding to the visuotopically organized regions defined by their connectivity patterns. Consideration of the retino-recipient zone as an extension of the LGNd-MIN complex is discussed.

Enhancement of plasma alpha-fetoprotein, as measured by sandwich-type radioimmunoassay, and induction of gamma-glutamyl transpeptidase-positive hepatic cell foci in rats fed benzo[a]pyrene

Male Fischer rats were fed semipurified diets containing 0, 1, 100, and 1000 ppm benzo[a]pyrene (BaP) for 6 or 13 wk. Plasma samples were assayed for alpha-fetoprotein (AFP) by a new sandwich-type radioimmunoassay (RIA) utilizing a special controlled porous-glass solid phase. This procedure is described in detail. Significant AFP elevation (p less than or equal to 0.01) was observed in the highest BaP treatment group after 5 wk of treatment. The 1 and 100 ppm Bap groups exhibited no AFP elevation throughout the study. Liver sections from the 1000 ppm groups had discrete gamma-glutamyl transpeptidase (GGT)-positive foci 10-20 cells in diameter by the 6th wk. GGT-positive foci were not evident in liver sections from the other treatment groups. Thus a high level of dietary BaP appears to rapidly alter rat liver cells, indicating hepatic neoplasia.

Metabolism of zinc and copper in the neonate: accumulation of Cu in the gastrointestinal tract of the newborn rat

1. The concentration of copper in the rat intestine was found to increase rapidly after birth to a maximum greater than 140 microgram/g wet weight at 2 d of age and then to decline, at first slowly to 90 microgram/g wet weight on day thirteen and then rapidly to 40 microgram/g and 3 . 4 microgram/g wet weight on the 15th and 19th day respectively. The intestinal concentration of Zn, which doubled between 1 d prepartum and 2 d post partum, also fell slowly until 10 d of age, but thereafter remained constant. 2. From the 2nd to the 15th day post partum approximately 60% of the total Cu and 50% of the total zinc in the intestine was located in the soluble fraction of the tissue. Most of the Zn in this fraction was bound by proteins of molecular weights greater than 13700 daltons, whereas most of the Cu was present as an extremely polydisperse complex of lower molecular weight. This complex in the intestine of the 5-d-old rat, in contrast with the soluble proteins of higher molecular weight, did not incorporate either 3H or 35S within 4 h of the administration of L-[4,5-3H]leucine and L-[35S]cystine. 3. The loss of Cu from the intestine between the 13th and 15th day of post-natal age occurred mainly from this complex and was accompanied by the transient appearance of Cu in a fraction of low molecular weight. 4. At 21 d of age the soluble fraction of the intestine contained only a small amount of Cu. This was distributed between two protein fractions, one of which contained Zn and appeared to be a metallothionein. 5. The results are discussed in relation to the control of Zn and Cu absorption.

Metabolism of zinc and copper in the neonate: accumulation and function of (Zn, Cu)-metallothionein in the liver of the newborn rat

1. Measurements were made of the hepatic concentrations and contents of total and thionein-bound zinc and copper in late foetal and newborn rats and of the distribution of these metals between the particulate and soluble components of the liver. 2. The decrease in the hepatic concentration of thionein-bound Zn, which occurred with age after birth, was proportional to the increase in liver weight until the 16th day post partum; thereafter it was greater. 3. Throughout the period from birth to 25 d of age the Zn concentration remained constant in the cytosolic non-thionein fraction (i.e. total cytoplasmic Zn--thionein-bound Zn), but decreased in other compartments of the liver. 4. The same constant concentration of cytoplasmic non-thionein-bound Zn also was observed in animals with reduced total hepatic Zn contents, but normal body-weights, and in 20-d-old Zn-deficient pups. 5. The concentration of thionein-bound Cu increased significantly only between the 6th and 14th day post partum. The age-related variations in Cu contents of the particulate components closely paralleled those in the whole liver, whereas the Cu contents of the cytosolic thionein and non-thionein fractions did not increase appreciably until after the 10th day. 7. It is concluded that the cytosolic non-thionein fraction of newborn rat liver may contain particularly important metabolic sites that require Zn and a major function of Zn-thionein is to regulate the supply of the metal to these sites. As, from birth to 26 d of age, the sum of the concentrations of thionein-bound Zn and Cu was correlated with whole liver Zn, the accumulation of Cu as a soluble metallothionein seems to be a secondary event, dependent on the hepatic Zn concentration.

The crystal structure of solvated Pt[CH3C(CH2PPh2)3][P(C6H4F)3]

The molecular structure of the compound Pt(tripod)P(C6H4F)3½C4H8O where tripod = CH3C- (CH2PPh2)3, has been determined by single-crystal X-ray diffraction methods at 295 K. Crystals are triclinic, space group P1. Z 2, a 13.497(1), b 14.803(2), c 13.898(2) A, α 91.914(7), β 102.304(6), γ 97.319(6)°. Diffractometry (Mo Kα) has provided significant [I ≥ 3σ(I)] Bragg intensities for 9528 independent reflections within 0 < (sin θ;)/λ ≤ 0.705 Ǻ-1.The structure has been refined by least-squares methods to R 0.040. The coordination of the zero-valent platinum atom is distorted tetrahedral with three Pt-P bonds, of lengths 2.292(1), 2.297(1), 2.303(1) Ǻ, to phosphorus atoms of the tripod ligand, and a fourth Pt-P(C6H4F)3 bond of length 2.261(1) Ǻ. The P-Pt-P bond angles involving the phosphorus atom of the monodentate ligand are large [118.23(5), 127.18(6), 122.20(5)°], whereas the steric constraints related to the tripod ligand are reflected in the other P-Pt-P bond angles, none of which are very different from 90° [91.26(5), 99.56(5), 90.79(5)°]. We suggest that the short Pt-P(C6H4F), bond is qualitatively explained by greater 's' electron character in the metal σ orbital used in bonding with the monodentate ligand, and conversely more 'p' electron character in the platinum σ orbitals used in bonding with the tripod ligand. We discuss the lack of significant evidence for platinum to phosphorus π-bonding effects in the observed Pt-P bond lengths.

Speech considerations with maxillary advancement procedures

Advancement of the maxilla has the potential to cause hypernasal speech, especially in patients with repaired cleft palates. Findings in three patients whose speech was at risk with maxillary advancement procedures are discussed, as well as their management. Diagnostic guidelines for identifying patients whose speech may be adversely affected by maxillary advancement are also presented.

Fatal myeloencephalopathy caused by intrathecal vincristine

Vincristine sulfate was inadvertently given intrathecally to a woman with lymphoma, producing ascending sensory and motor dysfunction followed by encephalopathy and death. Pathologically, neurons were swollen by aggregates of neurofilaments similar to the neurofilaments described in experimental models of vincristine neurotoxicity.

Percutaneous extraction of retained gallstones via the T-tube track-British experience of 131 cases

Twenty-six hospitals replied to a questionnaire asking for experience in the technique for percutaneous extraction of retained gallstones via the T-tube track. One hundred and thirty-one patients were treated. The overall success rate (complete clearance of residual stones) was 70% and a marked improvement in success rates with increasing operator experience has been demonstrated. The complication rate remains acceptably low during the learning phase. There was no mortality. There were 12 complications (9.2%): pancreatitis (one case), fever (seven cases) and track perforation (four cases). One patient required surgery for complication (track perforation). Variations in technique and management are described.

Congenital neurosyphilis and juvenile paresis: a forgotten entity?

Juvenile neurosyphilis is rare and may be arrested or modified in the early stage by antibiotic treatment for intercurrent infections. Inadequate treatment may weaken the signs and symptoms of neurosyphilis so much that a high index of clinical suspicion is required for early and correct diagnosis. It should be remembered, however, that benzathine penicillin does not constitute adequate treatment for neurosyphilis.