Kinetics of phase separation in polymer-solvent mixtures

We investigate the kinetics of phase separation in systems with a strong asymmetry in the mobility. This simple model system mimics the segregation kinetics of polymer-solvent mixtures, where the polymer-rich phase forms a low-mobility gel. We obtain detailed numerical results for this model, both without and with thermal noise. In the absence of thermal noise, we find that domain growth is slowed down drastically when the low-mobility phase percolates the system. However, thermal noise restores rapid domain growth through a Brownian coalescence mechanism.

Improved renal preservation with PB-3 flush solution during 72 h of cold storage

Previously, PB-2 flush solution has been found to be superior to Collins 2 solution (C-2) in extending renal viability in the dog. To further characterize preservation mechanisms, we studied mitochondrial oxidative function during 72 h of cold storage comparing PB-3, UW-1, and C-2 flush storage solutions. Complex 1 dependent mitochondrial oxidative phosphorylation (MOP) was found to be significantly less (P < 0.001) at 5 h and 72 h of cold storage (P < 0.001) for the C-2 compared to the other flush groups. Complex 2 dependent MOP had parallel results, having significantly less function (P < 0.002) at 5 h and 72 h (P < 0.02) of cold storage in the C-2 group compared to the other groups. PB-3 and UW-1 solutions were noted to be comparable, suggesting possible equivalent preservation efficacy. Nevertheless the components of PB-3 at the level of MOP contributed significantly to better preservation compared to C-2 solution.

Symptomatic volvulus due to mid gut malrotation in an adult

Anomalies of rotation and fixation of gut occur most commonly in the neonatal period and usually become symptomatic in infancy. We report an adult patient with symptomatic volvulus due to mid gut malrotation.

Specific roles of NMDA and AMPA receptors in direction-selective and spatial phase-selective responses in visual cortex

Cells in the superficial layers of primary visual cortex (area 17) are distinguished by feedforward input from thalamic-recipient layers and by massive recurrent excitatory connections between neighboring cells. The connections use glutamate as transmitter, and the postsynaptic cells contain both NMDA and AMPA receptors. The possible role of these receptor types in generating emergent responses of neurons in the superficial cortical layers is unknown. Here, we show that NMDA and AMPA receptors are both involved in the generation of direction-selective responses in layer 2/3 cells of area 17 in cats. NMDA receptors contribute prominently to responses in the preferred direction, and their contribution to responses in the nonpreferred direction is reduced significantly by GABAergic inhibition. AMPA receptors decrease spatial phase-selective simple cell responses and generate phase-invariant complex cell responses.

Anti-inflammatory activity of Dalbergia sissoo leaves

The possible anti-inflammatory activity of the 90% ethanolic extract of Dalbergia sissoo leaves (DSELE) was studied in different models of inflammation in rats after oral administration at doses of 100, 300 and 1000 mg/kg. DSELE significantly inhibited carrageenin, kaolin and nystatin-induced paw oedema, as well as the weight of granuloma induced by a cotton pellet. It also inhibited dye leakage in acetic acid-induced vascular permeability test in mice. DSELE was devoid of ulcerogenic effect on the gastric mucosa of rats in acute and chronic tests. In acute toxicity studies, it was found to be safe up to 10.125 g/kg, p.o. in the rat. It was concluded that the D. sissoo leaf extract possessed significant anti-inflammatory activity (in acute, sub-acute and chronic models of inflammation) without any side effect on gastric mucosa.

Adaptation-induced plasticity of orientation tuning in adult visual cortex

A key emergent property of the primary visual cortex (V1) is the orientation selectivity of its neurons. The extent to which adult visual cortical neurons can exhibit changes in orientation selectivity is unknown. Here we use single-unit recording and intrinsic signal imaging in V1 of adult cats to demonstrate systematic repulsive shifts in orientation preference following short-term exposure (adaptation) to one stimulus orientation. In contrast to the common view of adaptation as a passive process by which responses around the adapting orientation are reduced, we show that changes in orientation tuning also occur due to response increases at orientations away from the adapting stimulus. Adaptation-induced orientation plasticity is thus an active time-dependent process that involves network interactions and includes both response depression and enhancement.

I-cell disease (Mucolipidosis II)

I-cell disease (Mucolipidosis II) is one of the lysosomal storage diseases which presents in the neonatal period, and within six months will phenotypically resemble the severe forms of the group of disorders called the "mucopolysaccharidoses" but without mucopolysacchariduria. In Mucolipidosis II, fibrocytes exhibit "abnormal lysosomes". Activities of several lysosomal enzymes are low in fibroblast cultures but high in mucolipidosis II serum. We present a patient with I-cell disease diagnosed on the basis of clinical, radiological and biochemical features. The mother of this child was pregnant and the fetus was also found to be affected.

Induction of visual orientation modules in auditory cortex

Modules of neurons sharing a common property are a basic organizational feature of mammalian sensory cortex. Primary visual cortex (V1) is characterized by orientation modules--groups of cells that share a preferred stimulus orientation--which are organized into a highly ordered orientation map. Here we show that in ferrets in which retinal projections are routed into the auditory pathway, visually responsive neurons in 'rewired' primary auditory cortex are also organized into orientation modules. The orientation tuning of neurons within these modules is comparable to the tuning of cells in V1 but the orientation map is less orderly. Horizontal connections in rewired cortex are more patchy and periodic than connections in normal auditory cortex, but less so than connections in V1. These data show that afferent activity has a profound influence on diverse components of cortical circuitry, including thalamocortical and local intracortical connections, which are involved in the generation of orientation tuning, and long-range horizontal connections, which are important in creating an orientation map.

Anomalous colloidal stability of protein coated polystyrene latex beads studied by small angle light scattering

Results of small angle laser light scattering experiments carried out on polystyrene latex beads coated with lysate of Plasmodium falciparum (Pf) antigen (Ag) and human seropositive sera (10:1 ratio) are reported for various NaCl concentrations (0-300 mM). The protein coated beads showed time-dependent coagulation. The normalised intensity of scattered light I(s)(t)/I(0) showed I(s)(t)/I(0)=1+(Gammat)(delta) behaviour with the coagulation rate, Gamma and exponent, delta showing anomalous dependence on NaCl concentration. The coagulation rate exhibited strong increase up to NaCl concentration of 50 mM, above this and up to 300 mM the coagulation rate was found to remain independent of NaCl concentration yielding non-DLVO behaviour. The same was true for delta which increased from 1.04+/-0.06 to 6.94+/-0.07 as NaCl concentration was raised from 0 to 50 mM. Above 50 mM it remained constant with delta=6.94+/-0.07. Results are discussed through Smoluchowski aggregation kinetics and theoretical construction of interparticle interaction potentials relevant to our problem.

Rewiring cortex: the role of patterned activity in development and plasticity of neocortical circuits

Visually driven activity is not required for the establishment of ocular dominance columns, orientation columns, and long-range horizontal connections in visual cortex, although spontaneous activity appears to be necessary. The role of activity may be instructive or simply permissive; evidence for an instructive role requires inquiry into the role of the pattern of activity in shaping cortical circuits. The few experiments that have probed the role of patterned activity include the effects of artificial strabismus, artificial stimulation of the optic nerve, and rewiring visual projections from the retina to the auditory thalamus and cortex. These experiments demonstrate that patterned activity is vital for the maintenance of thalamocortical, local intracortical, and long-range horizontal connections in cortex.

Heterotopic ossification in moyamoya disease: a case report

Moyamoya disease is a rare disorder of cerebrovascular circulation. A review of the literature failed to reveal the association of heterotopic ossification in patients with this disease; such a case is now presented. The patient described had atraumatic intracranial hemorrhage, was in a coma for a period of time, underwent ventriculostomy and shunt placement, and was left with residual spastic hemiparesis. Evidence of heterotopic ossification around the hemiparetic shoulder and hip was subsequently noted on radiographic studies and was managed conservatively. Heterotopic ossification may be a rare complication of the neurological deficits associated with moyamoya disease and needs careful consideration when joint stiffness persists, despite usual conservative measures.

Isolation and characterization of monomeric and dimeric CP47-reaction center photosystem II complexes

Using the detergents n-dodecyl beta-D-maltoside and heptyl thioglycopyranoside, a subcore complex of photosystem II (PSII) has been isolated that contains the chlorophyll-binding protein, CP47, and the reaction center components, D1, D2, and cytochrome b559. We have found, by using sucrose density centrifugation, that the resulting preparation consisted of a mixture of dimeric and monomeric forms of the CP47 reaction center (RC) complex, having molecular masses of 410 +/- 30 and 200 +/- 28 kDa, respectively, as estimated by size exclusion chromatography. The level of the dimer in the preparation is significantly higher than the monomeric form. Both the monomer and dimer contain the proteins CP47, D1, and D2 and the alpha- and beta-subunits of cytochrome b559. Analyses by mass spectrometry and N-terminal sequencing showed that both forms of the CP47-RC complex contain the products of the psbI, psbTc (chloroplast gene), and psbW with molecular masses of 4195.5, 3849.6, and 5927.4 Da, respectively. In contrast to the monomeric form, the CP47-RC dimer contained two extra proteins with low molecular weights, identified as the products of the psbL and psbK genes having molecular masses of 4365.5 and 4292.1, respectively. It was also found that the dimer contained slightly more molecules of chlorophyll a (21 +/- 2.5) than the monomer (18 +/- 1.5), a characteristic also observed in the room temperature absorption spectrum by comparing the ratio of absorption at 416 and 435 nm. Of particular note was the finding that the dimer, but not the monomer, contained plastoquinone-9 (estimated to be 1.5 +/- 0.3 molecules per RC). The results indicate that the CP47-RC monomer is derived from the dimeric form of the complex, and therefore the latter is likely to represent an in vivo conformation. The PsbTc as well as the PsbI and PsbW proteins are identified as being intimately associated with the D1 and D2 proteins, and in the case of the dimer, importance is placed on the PsbL and PsbK proteins in sustaining plastoquinone binding and maintenance of the dimeric organization. Assuming only one copy of the alpha- and beta-subunits of cytochrome b559, the monomeric and dimeric forms of the complex would be expected to contain 21 and 23 x 2 transmembrane helices, respectively.

Purification and determination of intact molecular mass by electrospray ionization mass spectrometry of the photosystem II reaction center subunits

A reverse phase high pressure liquid chromatography purification system for the rapid separation of photosystem II reaction center proteins free of salts and detergents is described. This procedure results in the isolation of the three small subunits: alpha- and beta-subunits of cytochrome b559 and PsbI protein, with near base-line resolution between each peak, although the D1 and D2 proteins were partially deconvoluted. The molecular masses obtained by electrospray ionization mass spectrometry for the purified beta-subunit of cytochrome b559, alpha-subunit of cytochrome b559, and the PsbI protein, 4,394.8 +/- 0.4, 9,283.7 +/- 0.8, and 4,209.5 +/- 0.4 Da, respectively, are in excellent agreement with values obtained from previous characterization studies (Sharma, J., Panico, M., Barber, J., and Morris, H. R. (1997) J. Biol. Chem. 272, 3935-3943). Direct electrospray analysis of the D1 and D2 proteins suggests that these components exist in heterogeneous forms. The molecular mass ascribed to a predominant form of the D1 protein, 38, 040.9 +/- 6.5 Da, and the D2 protein, 39,456.1 +/- 7.7, are also in agreement with those expected for the mature nonphosphorylated states of these subunits.

Primary structure characterization of the photosystem II D1 and D2 subunits

Mass spectrometry techniques have been applied in a protein mapping strategy to elucidate the majority of the primary structures of the D1 and D2 proteins present in the photosystem II reaction center. Evidence verifying the post-translational processing of the initiating methionine residue and acetylation of the free amino group, similar to those reported for other higher plant species, are presented for the two subunits from pea plants (Pisum sativum L.). Further covalent modifications observed on the D1 protein include the COOH-terminal processing with a loss of nine amino acids and phosphorylation of Thr2. In addition, the studies reported in this paper provide the first definitive characterization of oxidations on specific amino acids of the D1 and D2 proteins. We believe that these oxidations, and to a much lesser extent the phosphorylations, are major contributors to the heterogeneity observed during the electrospray analysis of the intact subunits reported in the accompanying paper (Sharma, J., Panico, M., Barber, J., and Morris, H. R. (1997) J. Biol. Chem. 272, 33153-33157). Significantly, all of the regions that have been identified as those particularly susceptible to oxidation are anticipated (from current models) to be in close proximity to the redox active components of the photosystem II complex.

Aortic stenosis in hypoplastic right heart syndrome, associated with interstitial deletion of chromosome 2

This report describes a rare case of moderate to severe valvular aortic stenosis in the setting of severe tricuspid stenosis, pulmonary atresia with intact interventricular septum and right ventricular dependent coronary circulation. We discuss the clinical, hemodynamic, echocardiographic and angiocardiographic findings on this rare case and comment on accompanied malformations, with its possible association observed to the interstitial deletion of band q22 or q24 of the long arm of chromosome 2.

Characterization of the low molecular weight photosystem II reaction center subunits and their light-induced modifications by mass spectrometry

A sensitive and simple reverse phase HPLC purification scheme was developed for the rapid separation of the small protein subunits from photosystem II reaction center preparations. The precise molecular masses of the alpha- and beta-subunits of cytochrome b559 and the psbI gene product from pea plants, found to be 4394.6 +/- 0. 6, 9283.6 +/- 0.7, and 4209.5 +/- 0.5 Da, respectively, were then successfully determined for the first time by electrospray- and fast atom bombardment-mass spectrometry. Discrepancies between the molecular weights assigned and those calculated from the respective DNA sequences were observed for alpha- and beta-subunits of cytochrome b559. Currently, the nucleotide sequence of the psbI gene product from pea plants is not available. Application of novel mapping and sequencing strategies has assured the elucidation of full primary structures of all of the purified subunits. The modifications identified here include the post-translational processing of the initiating methionine on both subunits of cytochrome b559, NH2-terminal acetylation and an mRNA editing site at residue 26 (Ser --> Phe) on the beta-subunit, and retention of the NH2-terminal formyl-Met on the psbI gene product. In addition, specific oxidation of a single amino acid residue was identified on the psbI gene product and the beta-subunit purified from light-treated reaction center preparations. Overall, these studies provide the first detailed primary structural characterization of the small subunits of the reaction center complex and their associated light-induced modifications.

Orientation maps of subjective contours in visual cortex

Responses to subjective contours in visual cortical areas V1 and V2 in adult cats were investigated by optical imaging of intrinsic signals and single-unit recording. Both V1 and V2 contain maps of the orientation of subjective gratings that have their basis in specific kinds of neuronal responses to subjective orientations. A greater proportion of neurons in V2 than in V1 show a robust response to subjective edges. Through the use of subjective stimuli in which the orientation of the luminance component is invariant, an unmasked V1 response to subjective edges alone can be demonstrated. The data indicate that the processing of subjective contours begins as early as V1 and continues progressively in higher cortical areas.

Sequence and unusual 3' flanking region of the rat tRNA[Ser]Sec gene

The single rat selenocysteine tRNA (tRNA[Ser]Sec) locus, including flanking sequence, was isolated by molecular cloning and its nucleotide (nt) sequence determined. In addition to the identification of likely regulatory elements 5' of this gene, this analysis also revealed a novel 3' repeat element consisting of three and a half repetitions of a 34-nt unit.

Correlative histochemical and biochemical studies on acetylcholinesterase activity during ovulation in the rat

A correlative histochemical and biochemical study has been made of the changes in acetylcholinesterase (AChE)-positive sites during ovulation induced in immature female albino rats with exogenous gonadotrophins. Acetylcholinesterase is the marker for cholinergic innervation. In histochemical observations, AChE+ve sites were localized in typical perivascular position and the intensity and number of enzyme-positive sites around the Graafian follicle gradually increased during follicular maturation and ovulation but stromal AChE-activity did not show any appreciable change. Biochemical estimation of the enzyme supports these observations. The electronmicroscopic and histological observations of the structural changes in nerves accompanying ovulation have also been enumerated and the role of cholinergic nerves in neuromuscular control of ovulation is discussed.

Prognostic significance of insulin-like growth factor-binding protein expression in axillary lymph node-negative breast cancer

BACKGROUND

Cellular proliferation, as measured by S-phase fraction, is an important predictor of breast cancer prognosis. The insulin-like growth factors (IGFs) have been shown to regulate proliferation in both normal and neoplastic cells by interacting with specific cell surface receptors. In addition to these receptors, high-affinity extracellular binding proteins also modulate IGF action. These insulin-like growth factor-binding proteins (IGFBPs) could influence breast cancer growth and, like other biological parameters of proliferation, could be related to prognosis.

PURPOSE

To test whether IGFBP expression was related to other biological parameters and disease-free survival, we measured IGFBP expression in 238 lymph node-negative primary breast cancer specimens.

METHODS

Proteins were extracted from breast cancer specimens and analyzed by semiquantitative IGF-I ligand blotting for IGFBP expression. IGFBP expression levels were compared to tumor size, age, S-phase fraction, DNA ploidy, and estrogen and progesterone receptor expression by Spearman correlation.

RESULTS

Binding protein (BP)-2, BP-3, BP-4, and BP-5 were identified in breast cancer extracts. Estrogen receptor expression was positively correlated with BP-2 (Spearman correlation coefficient, rs = .262; P = .0001), BP-4 (rs = .313; P = .0001), and BP-5 (rs = .242; P = .0002). Similar correlations between progesterone receptor and BP-2, BP-4, and BP-5 were also found. BP-3 was inversely correlated with age (rs = -.251, P = .0001). BP-4 was weakly inversely correlated with tumor size (rs = -.141; P = .0295) and S-phase fraction (rs = -.216; P = .0025). Since tumor size and S-phase fraction are powerful predictors of prognosis in node-negative breast cancer, we examined the value of BP-4 as a predictor of disease-free survival. When stratified by tumor size, patients with large (> 2 cm) tumors that expressed low levels of BP-4 had improved survival when compared with patients with large tumors and high BP-4 levels (P = .001).

CONCLUSIONS

IGFBPs can be detected in breast cancer specimens, and their level of expression correlates with other known biological parameters of breast cancer. Large tumors with low levels of BP-4 have relatively favorable prognoses.

IMPLICATIONS

These data suggest that the IGFBPs may play a role in breast cancer biology and that BP-4 levels, analyzed in conjunction with tumor size, may have prognostic significance.

Use of N,N'-polymethylenebis(iodoacetamide) derivatives as probes for the detection of conformational differences in tubulin isotypes

Mammalian brain tubulin is an alpha beta heterodimer; both alpha and beta exist in 6-7 isotypic forms which differ in their amino acid sequences. By the use of isotype-specific monoclonal antibodies, we have previously shown that we can purify the alpha beta II, alpha beta III, and alpha beta IV tubulin dimers from bovine brain. We have also observed that these isotypes differ in their distribution in vivo and their polymerization and drug-binding properties in vitro. We have now explored the question of whether the isotypically purified dimers differ in their overall conformation using as probes compounds of the N,N'-polymethylenebis (iodoacetamide) series which are known to form discrete intrachain cross-links in beta-tubulin. These compounds have the structure ICH2CONH(CH2)nNHCOCH2I. One of these cross-links, designated beta s, is between cys12 and either cys201 or cys211. The other, designated beta*, is between cys239 and cys354. The beta* cross-link forms in alpha beta II and alpha beta IV but not in alpha beta III; this is not surprising in view of the fact that alpha beta III has serine at position 239 instead of cysteine. However, alpha beta III is also unable to form the beta s cross-link, although it appears to have all three cysteines which may be involved in the cross-link. This suggests that at least one of the sulfhydryls involved in the cross-link may be inaccessible in alpha beta III. Although both alpha beta II and alpha beta IV can form the beta s cross-link, the dependence on cross-linker chain length is different. alpha beta II forms beta s with derivatives in which n = 2, 4, 5, 6, and 7 but not with those in which n = 3 or 10. In contrast, alpha beta IV forms beta s with derivatives in which n = 2, 3, 4, 5, 6, 7, and 10. These results imply that the beta s sulfhydryls are slightly more accessible in alpha beta IV and are therefore less dependent on the conformation of the cross-linker to react with it. It appears, therefore, that the alpha beta II, alpha beta III, and alpha beta IV dimers each have unique conformations. This may help to explain the different assembly and drug-binding properties of these dimers.

Recombinant insulin-like growth factor binding protein-1 inhibits IGF-I, serum, and estrogen-dependent growth of MCF-7 human breast cancer cells

The insulin-like growth factors (IGFs) are potent mitogens for breast cancer cells and their activity is modulated by high affinity binding proteins (IGFBPs). We have recently shown that IGFBP-1 purified from human amniotic fluid neutralizes IGF-I-dependent growth of MCF-7 cells. In this study we examined the effects of recombinant IGFBP-1 (rBP-1) on IGF-I, estradiol (E2), and serum-induced monolayer and anchorage independent growth (AIG) of MCF-7 cells. Under serum-free conditions, rBP-1 had no effect on MCF-7 basal monolayer growth. However, 40 nM rBP-1 completely blocked the mitogenic action of both IGF-I and 5% charcoal stripped serum (CSS). This concentration of rBP-1 partially inhibited E2-induced growth, while 80 nM rBP-1 completely abolished E2 mitogenicity. The addition of either excess IGF-I or 5 nM [Arg3]IGF-I, a species that does not bind IGFBPs, neutralized rBP-1 inhibitory effects. In AIG assays, 80 nM rBP-1 reduced colony number by at least 70% and decreased colony size in all treatment groups compared to control. We examined rBP-1 effects on both IGF-I binding to MCF-7 membranes and activation of type I IGF receptor (IGFR1) and found that 80 nM rBP-1 reduced IGF-I receptor binding to levels of nonspecific binding and completely abolished ligand-dependent IGFR1 phosphorylation. However, neither treatment with 5% CSS nor exposure to E2 resulted in IGFR1 phosphorylation suggesting that different mechanism(s) are responsible for rBP-1 inhibitory action under this condition. Our data suggest rBP-1 may serve as an antagonist of human breast cancer growth by interfering with growth factor-mediated cell proliferation.

Solitary rectal ulcer syndrome and colitis cystica profunda--a clinico-pathological review

Twenty cases of solitary rectal ulcer syndrome (SRUS) and three cases of colitis cystica profunda (CCP) diagnosed between 1985 to 1990 were studied retrospectively. Clinical features, sigmoidoscopic findings and histopathology of the above lesions were reviewed. Haematoxylin and Eosin, Masson's Trichome, and high iron diamine Alcian blue staining was done in all the cases. Histopathologic examination helps in diagnosing the benign condition of the rectum viz. SRUS and CCP which are considered malignant clinically. Since an overlap of histopathological features were seen in SRUS and CCP, both can be considered as one entity, which has been highlighted in our study. Fibromuscular obliteration of lamina propria is the hallmark of the lesion.

Treatment of prolonged ventricular fibrillation. Immediate countershock versus high-dose epinephrine and CPR preceding countershock

BACKGROUND

Early countershock of ventricular fibrillation has been shown to improve immediate and long-term outcome of cardiac arrest. However, a number of investigations in the laboratory and in the clinical population indicate that immediate countershock of prolonged ventricular fibrillation most commonly is followed by asystole or a nonperfusing spontaneous cardiac rhythm, neither of which rarely respond to current therapy. The use of epinephrine in doses greater than those currently recommended has recently been shown to improve both cerebral and myocardial perfusion during cardiopulmonary resuscitation (CPR). The purpose of this study was to compare cardiac resuscitation outcome between immediate countershock of prolonged ventricular fibrillation with high-dose epinephrine therapy and conventional CPR before countershock of prolonged ventricular fibrillation in a canine model.

METHODS AND RESULTS

After sedation, intubation, induction of anesthesia, and instrumentation, ventricular fibrillation was electrically induced in 28 dogs. After 7.5 minutes of ventricular fibrillation, animals were randomly allocated to two treatment groups: group 1, immediate countershock followed by recommended advanced cardiac life support (ACLS) interventions, or group 2, 0.08 mg/kg epinephrine and manual closed-chest CPR before countershock and ACLS. In both groups, ACLS was continued until a spontaneous perfusing rhythm was restored or for 20 minutes (total arrest time, 27.5 minutes). A spontaneous perfusing rhythm was restored in three of 14 group 1 animals and in nine of 14 group 2 animals (p = 0.014 by sequential analysis method of Whitehead). Coronary perfusion pressure (aortic minus right atrial pressure during CPR diastole) before countershock was significantly greater in group 2 (21 +/- 7 mm Hg) when compared with mean circulatory pressure in group 1 (9 +/- 8, p less than 0.01).

CONCLUSIONS

The findings of this study suggest that a brief period of myocardial perfusion before countershock improves cardiac resuscitation outcome from prolonged ventricular fibrillation.

Ionized hypocalcemia during prolonged cardiac arrest and closed-chest CPR in a canine model

STUDY BACKGROUND

Free or ionized calcium (Ca+2) is known to play a critical role in normal cardiovascular function, and Ca+2 administration in the setting of ionized hypocalcemia has been shown to improve indexes of cardiac function. The value of Ca+2 administration in the setting of cardiac arrest and resuscitation is unproven and controversial, in large part because ionized Ca+2 levels during cardiac arrest and resuscitation have not been adequately studied and exogenous calcium therapy may worsen ischemic cellular injury.

STUDY PURPOSE

To measure free calcium during prolonged cardiac arrest and CPR in a canine model.

METHODS AND MEASUREMENTS

Central arterial and venous catheters were positioned in nine dogs, and ventricular fibrillation (VF) was induced electrically. After seven and one-half minutes of VF, countershocks were administered, and CPR was initiated and performed in accordance with current recommendations for 20 minutes. At five-minute intervals during resuscitation efforts, arterial pH, ionized Ca+2, and lactate as well as aortic pressure were measured.

RESULTS

During resuscitation, average systolic arterial pressure was 50 mm Hg. Within five minutes of instituting CPR, ionized Ca+2 significantly decreased from control values (5.1 +/- 0.1 at control to 4.0 +/- 0.1 mg/dL); after 20 minutes of attempted resuscitation, it averaged 3.2 +/- 0.2 mg/dL (P less than .05 vs control). There was no change in total Ca+2 during the arrest period (9.2 +/- 0.5 at control to 8.6 +/- 0.8 mg/dL at 27.5 minutes). Arterial lactate significantly increased throughout the arrest and resuscitation period (1.9 +/- 0.2 at control to 7.5 +/- 0.4 mM/L at 27.5 minutes). A significant correlation was demonstrated between ionized Ca+2 and lactate concentrations (r = -.72, P less than .001) but not between ionized calcium and pH (r = -.22, P greater than .20).

CONCLUSION

Ionized hypocalcemia occurs during prolonged cardiac arrest and resuscitation, and ionized hypocalcemia during prolonged arrest and resuscitation may be due to binding by lactate, as has been demonstrated in vitro.

Non invasive continuous anterior fontanel tension monitoring in neonates

Anterior fontanel tension (AFT) has been shown to reflect the intracranial pressure (ICP). A new transducer was designed for AFT measurement which overcomes the problems of replacement in subsequent use. Using the transducer AFT was monitored noninvasively over extended periods in about 200 normal and sick neonates. The results indicate that the technique can be used to identify elevated pressure due to different disease conditions and it has a potential to help in understanding physiological and pathological mechanisms causing alterations in the normal cerebrospinal dynamics. Further studies are underway to establish the full potentials of the technique.

Internal fixation in 50 cases of Galeazzi fracture

Fifty Galeazzi fracture dislocations were treated by early open reduction, internal fixation, and cancellous bone grafting. After 1 year, 40 cases were good, 8 fair, and 2 poor. We conclude that early open reduction and rigid internal fixation reestablishes the normal relationship of the fractured fragments and the distal radioulnar joint without repair of the ligaments.

Buffers and H2O2 reduce neuronal death and/or enhance differentiation of neurons and astrocytes in dissociated mouse brain cultures

Tissue of the mammalian central nervous system (CNS) undergoes complex and uncoordinated pathological responses upon injury. Efforts to develop pharmacological approaches to achieve functionally meaningful regeneration largely have been unsuccessful. Assuming that anoxia and drop in tissue H are initiating factors in most pathological sequences consequent to CNS injury, we studied the effects of increasing the buffering and oxygenating capacities of the medium on dissociated embryo brain cultures. The presence of H2O2 in the medium led to greatly enhanced neuronal survival and/or differentiation. Increased buffering capacity favored enhanced neurite outgrowth with remarkable elongation of fibers. A combination of the two gave a synergistic effect in which both of the above responses were seen. Both buffers and H2O2 enhanced astrocytic differentiation and extension of processes while reducing DNA synthesis. The results favor the view that attempts to encourage self-repair in CNS tissue or to enhance repair of CNS damage with potential therapeutic agents or procedures should be carried out in the context of a near optimal environment in which, at the least, pH and pO2 values are stably maintained within normal operational limits.

Dehydroepiandrosterone and its sulfated derivative reduce neuronal death and enhance astrocytic differentiation in brain cell cultures

Human studies of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEA-S) have shown age-related changes in serum levels of these two sex hormone precursors. The levels of both DHEA and DHEA-S are characterized by monotonic decreases after puberty in females and after 20-24 yr of age in males. Further studies have shown that DHEA and DHEA-S levels are significantly low or close to minimal at ages when the incidence of senile dementia of Alzheimer's type (SDAT) begins to increase. We propose that DHEA and DHEA-S play a significant role in normal function of neuronal cells and that supplementation with them may prevent neuronal loss and/or damage. In the present study, using methods of immunocytochemistry, autoradiography, and scanning electron microscopy, we show that a supplement of as little as 10(-8) M DHEA or DHEA-S greatly increases neuronal survival and differentiation and reduces astroglial proliferation rates in mouse brain cells in cultures. These results suggest that correcting the DHEA and the DHEA-S deficit may prevent and/or improve the SDAT condition in humans.

Numbers of myelinated and unmyelinated axons in the dorsal, lateral, and ventral funiculi of the white matter of the S2 segment of cat spinal cord

The present work determines the numbers of myelinated and unmyelinated axons in the dorsal, lateral, and ventral funiculi of the S2 segment of the cat spinal cord. The major finding is that unmyelinated axons are almost as numerous as myelinated axons in these pathways. The myelinated axons tend to be distributed uniformly, although there is a slight concentration of these fibers in the dorsal part of the lateral funiculus. By contrast, the unmyelinated fibers, although found in significant numbers in all parts of these funiculi, concentrate in the dorsal part of the lateral funiculus and in the dorsal funiculus. Of particular note are the unmyelinated fibers in the dorsal funiculus, because it is highly likely that some of these are sensory. The findings in this study will serve as a basis for experimental studies to determine the numbers, locations, and types of unmyelinated fibers in the white matter of the mammalian cord.

Infectious complications of vasectomy: a study of 200 cases

Semen and urine were cultured prior to vasectomy. Infectious complications only occurred in patients with positive semen and urine cultures and the offending organism was the same as that found in the semen and urine cultures. This evidence for an endogenous cause of postoperative vasectomy infection suggests that semen and urine cultures should be obtained prior to vasectomy. In this manner, the correct antimicrobial agent can be applied as an aid to rapid solution of a postvasectomy infection.

Cyatholaimidae (Nematoda) from the Canadian Pacific coast

Four species of Cyatholaimidae, represented in a study of free-living marine nematodes from Vancouver, Canada, are discussed. This paper includes the description of Marylynnia hopperi sp. nov., Paracyatholaimus vancouverensis sp. nov., and Propomponema websteri sp. nov., as well as the redescription of Paracyatholaimus pugettensis Wieser and Hopper, 1967.