Anti-NMDA receptor encephalitis presenting with focal non-convulsive status epilepticus in a child.

A previously healthy 9-year-old girl presented to an emergency department (ED) with headache, dizziness, blurry vision, and abnormal visual perceptions. She was diagnosed with migraine, treated symptomatically, and discharged. Over the course of days, she became progressively somnolent, and returned to the ED, where she was found to have a right inferior quadrantanopsia and sixth nerve palsy. Magnetic resonance imaging (MRI) of the brain showed gyral swelling of the left parieto-occipital lobe. Continuous electroencephalogram (EEG) monitoring revealed focal non-convulsive status epilepticus (NCSE) in the left occipital region. Cerebrospinal fluid (CSF) was positive for antibodies directed against the N-methyl-d-aspartate receptor (NMDAR). This case is the first report of anti-NMDAR encephalitis presenting with focal non-convulsive status epilepticus (NCSE).

Ceramides modulate protein kinase C activity and perturb the structure of Phosphatidylcholine/Phosphatidylserine bilayers.

We studied the effects of natural ceramide and a series of ceramide analogs with different acyl chain lengths on the activity of rat brain protein kinase C (PKC) and on the structure of bovine liver phosphatidylcholine (BLPC)/dipalmitoylphosphatidylcholine (DPPC)/dipalmitoylphosphatidylserine (DPPS) (3:1:1 molar ratio) bilayers using (2)H-NMR and specific enzymatic assays in the absence or presence of 7.5 mol % diolein (DO). Only a slight activation of PKC was observed upon addition of the short-chain ceramide analogs (C(2)-, C(6)-, or C(8)-ceramide); natural ceramide or C(16)-ceramide had no effect. In the presence of 7.5 mol % DO, natural ceramide and C(16)-ceramide analog slightly attenuated DO-enhanced PKC activity. (2)H-NMR results demonstrated that natural ceramide and C(16)-ceramide induced lateral phase separation of gel-like and liquid crystalline domains in the bilayers; however, this type of membrane perturbation has no direct effect on PKC activity. The addition of both short-chain ceramide analogs and DO had a synergistic effect in activating PKC, with maximum activity observed with 20 mol % C(6)-ceramide and 15 mol % DO. Further increases in C(6)-ceramide and/or DO concentrations led to decreased PKC activity. A detailed (2)H-NMR investigation of the combined effects of C(6)-ceramide and DO on lipid bilayer structure showed a synergistic effect of these two reagents to increase membrane tendency to adopt nonbilayer structures, resulting in the actual presence of such structures in samples exceeding 20 mol % ceramide and 15 mol % DO. Thus, the increased tendency to form nonbilayer lipid phases correlates with increased PKC activity, whereas the actual presence of such phases reduced the activity of the enzyme. Moreover, the results show that short-chain ceramide analogs, widely used to study cellular effects of ceramide, have biological effects that are not exhibited by natural ceramide.

Ultrastructure of the fragile X chromosome: new observations on the fragile site.

Using a nonair-drying modification of a method for longitudinal sectioning of metaphase spreads on glass slides [Wen et al., 1997], we have studied 14 preidentified X chromosomes (10 from fragile X specimens and 4 controls) with transmission electron microscopy (TEM). Four of 10 X chromosomes from fragile X specimens exhibited lighter chromatin density in the area of and distal to the fragile site, most pronounced under dark-field TEM. A clear line of separation at the fragile site locus was also observed by TEM in an X chromosome with no visible fragile site after Q-banding. We hypothesize that these areas of lighter density, including lines of separation, precede the appearance of the fragile site that is commonly observed using light microscopy.

Ceramides perturb the structure of phosphatidylcholine bilayers and modulate the activity of phospholipase A2.

The effects of a series of ceramide analogs with acyl chain lengths of 2, 6, 8 and 16 on the structure of diapalmitoylphosphatidylcholine (DPPC) bilayers and cobra venom phospholipase A2 (PL-A2) activity were studied using 2H-NMR and specific enzymatic assays. C2-ceramide did not induce a significant effect on the structure of DPPC bilayers and did not alter PL-A2 activity. C6- and C8-ceramides increased the ordering of the DPPC acyl chains, correlating with the inhibition of PL-A2 activity which was probably due to the increased lateral surface pressure. The long-chain C16-ceramide induced lateral phase separation of the bilayers into gel and liquid crystalline domains and activated PL-A2, as does natural ceramide (Huang et al. 1996). Taken together, the results strongly suggest a correlation between membrane defects induced by ceramide analogs and their effects on phospholipase A2 activity. Furthermore, the effects of short-chain ceramides on PL-A2 are different from those of natural ceramide, indicating that the cell-permeable short-chain ceramide analogs, widely used to study the shpingomyelin-dependent cellular signal transduction pathway, may not completely mimic the natural product.

Synergistic effects of diacylglycerols and fatty acids on membrane structure and protein kinase C activity.

The synergistic effects of diacylglycerol (DAG) and fatty acid (FA) in activating protein kinase C have been investigated by correlating their individual and combined effects on enzymatic activity and on membrane structure in phosphatidylcholine/phosphatidylserine (4:1) lipid mixtures using a combination of specific enzymatic assays and 31P and 2H NMR. Addition of DAGs and unsaturated FAs to the bilayers synergistically increased the tendency of the lipids to form nonbilayer phases with a concomitant increase in PKC activity until a maximum was achieved. Further increases in the DAG/FA concentration led to the formation of the nonbilayer lipid phases under the conditions of the PKC activity assays and correlated with decreased activity. The nonbilayer lipid phases still supported PKC activity, although with less than 50% efficiency as compared with the bilayer lipids. Long-chain saturated FA increased DAG-induced PKC activity by causing a lateral phase separation of gel (Lbeta) and liquid-crystalline (Lalpha) domains. Due to the preferential partitioning of DAGs into liquid-crystalline domains, the local DAG concentration increased in these domains, leading to an increase in PKC activity. Because a wide range of lipophilic compounds is capable of altering curvature stress, and therefore the tendency for nonbilayer phase formation in cellular membranes, these compounds would be expected to modulate PKC activity and the activities of a number of other membrane-associated enzymes that are sensitive to biophysical properties of lipid membranes.

Effects of histone and diolein on the structure of phosphatidylcholine/phosphatidylserine or phosphatidylcholine/phosphatidylglycerol bilayers.

The effects of the PKC substrate histone 1 and the PKC activator diolein (Ole2Gro) on the structure of phosphatidylcholine (PtdCho)/phosphatidylserine (PtdSer), or PtdCho/phosphatidylglycerol (PtdGro) bilayers were studied using 2H-NMR. The results showed that in PtdCho/PtdSer bilayers, histone preferentially increased order parameters of the acyl chains of the PtdSer, but not the PtdCho lipid component. This effect was additive with the effect of Ole2Gro, which equally increased the ordering of the acyl chains of both PtdCho and PtdSer. The histone-induced change in the conformation of the PtdCho headgroups in PtdCho/PtdSer bilayers indicated that positively charged residues of the bound histone are located above the lipid-water interface and their location was altered by the presence of Ole2Gro. A different picture was observed in the case of PtdCho/PtdGro bilayers; although the effect of Ole2Gro on both the PtdCho or the PtdGro components was similar to the case of the PtdCho/PtdSer bilayers, histone did not significantly affect the order parameters of PtdCho or PtdGro in either the absence or presence of Ole2Gro. The results indicate that histone 1 induces clustering of PtdSer in PtdCho bilayers which may contribute to PKC activation. Moreover, the observed differences in the interactions of histone with PtdCho/PtdSer compared with PtdCho/PtdGro bilayers may explain the higher efficiency of PtdSer in activating PKC.

Effects of dipalmitoylglycerol and fatty acids on membrane structure and protein kinase C activity.

The individual and combined effects of the saturated diacylglycerol (DAG) dipalmitin (DP) and saturated or polyunsaturated unesterified fatty acids (PUFAs) on both the structure of phosphatidylcholine/phosphatidylserine (PC/PS; 4:1 mol/mol) bilayers and on protein kinase C (PKC) activity were studied using 2H nuclear magnetic resonance (NMR) and enzyme activity assays. In the absence of DP, PUFAs only slightly activated PKC whereas palmitic acid had no effect. In the absence of fatty acids, DP induced lateral phase separation of the bilayer into liquid-crystalline and gel phases. Under these conditions virtually all DP was sequestered into the gel phase and no activation of PKC was observed. The addition of polyunsaturated arachidonic or docosahexaenoic acids to the DP-containing bilayers significantly increased the relative amounts of DP and other lipid components in the liquid-crystalline phase, correlating with a dramatic increase in PKC activity. Furthermore, the effect was greater with PS, resulting in an enrichment of PS in the liquid-crystalline domains. In the presence of DP, palmitic acid did not decrease the amount of gel phase lipid and had no effect on PKC activity. The results explain the observed lack of PKC-activating capacity of long-chain saturated DAGs as due to the sequestration of DAG into gel domains wherein it is complexed with phospholipids and thus not available for the required interaction with the enzyme.

Ceramide induces structural defects into phosphatidylcholine bilayers and activates phospholipase A2.

We studied the effects of bovine brain ceramide on the structure of dipalmitoylphosphatidylcholine (DPPC) bilayers and cobra venom phospholipase A2, (PL-A2) activity using 2H NMR and specific enzymatic assays. Addition of ceramide to DPPC at 45 degrees C induces lateral phase separation of the bilayers into regions of gel and liquid crystalline phases. The order parameters of the DPPC acyl chains in the liquid crystalline phase are only slightly affected by the presence of ceramide, indicating that the latter is largely partitioned in the gel phase of DPPC, whereas at 60 degrees C the presence of ceramide induced a large increase of the order parameters of DPPC side chains. The observed structural effects of ceramide correlated with ceramide-induced activation of cobra venom phospholipase A2 (PL-A2). Ceramide activated PL-A2 in a concentration-dependent manner, with a significant effect observed at 5 mol% ceramide, which caused an approximately 3-fold increase in PL-A2 activity. The results showing activation of PL-A2 by ceramide illustrate an additional feature of the biological effects of this second messenger and suggest the possibility of cross-talk between the sphingomyelinase and PL-A2 signal transduction pathways.

Effects of diacylglycerols on conformation of phosphatidylcholine headgroups in phosphatidylcholine/phosphatidylserine bilayers.

The effects of five diacylglycerols (DAGs), diolein, 1-stearoyl,2-arachidonoyl-sn-glycerol, dioctanoylglycerol, 1-oleoyl,2-sn-acetylglycerol, and dipalmitin (DP), on the structure of lipid bilayers composed of mixtures of phosphatidylcholine and phosphatidylserine (4:1 mol/mol) were examined by 2H nuclear magnetic resonance (NMR). Dipalmitoylphosphatidylcholine deuterated at the alpha- and beta-positions of the choline moiety was used to probe the surface region of the membranes. Addition of each DAG except DP caused a continuous decrease in the beta-deuteron quadrupole splittings and a concomitant increase in the alpha-deuteron splittings indicating that DAGs induce a conformational change in the phosphatidylcholine headgroup. Additional evidence of conformational change was found at high DAG concentrations (> or = 20 mol%) where the alpha-deuteron peaks became doublets indicating that the two alpha-deuterons were not equivalent. The changes induced by DP were consistent with the lateral phase separation of the bilayers into gel-like and fluid-like domains with the phosphatidylcholine headgroups in the latter phase being virtually unaffected by DP. The DAG-induced changes in alpha-deuteron splittings were found to correlate with DAG-enhanced protein kinase C (PK-C) activity, suggesting that the DAG-induced conformational changes of the phosphatidylcholine headgroups are either directly or indirectly related to a mechanism of PK-C activation. 2H NMR relaxation measurements showed significant increase of the spin-lattice relaxation times for the region of the phosphatidylcholine headgroups, induced by all DAGs except DP. However, this effect of DAGs did not correlate with the DAG-induced activation of PK-C.

Effects of diacylglycerols and Ca2+ on structure of phosphatidylcholine/phosphatidylserine bilayers.

The combined effects of the diacylglycerols (DAGs) with the various acyl chains and Ca2+ on the structure of phosphatidylcholine/phosphatidylserine (4:1 mole/mole) bilayers were studied using 2H- and 31P NMR. The following DAG- and Ca(2+)-induced bilayer perturbations were identified. 1) Increased tendency to form nonbilayer lipid phases was induced by diolein or stearoylarachidonoylglycerol, and was synergistically enhanced by the addition of Ca2+. 2) "Transverse" bilayer perturbation was induced by dioctanoylglycerol. The addition of this DAG caused increased ordering of the phospholipid acyl side chains in the region adjacent to the headgroup, with the concomitant decrease of the order toward the bilayer interior. 3) Separation of the phosphatidylcholine and phosphatidylserine bilayer components was induced by combinations of relatively high (1:5 mole/mole to phosphatidylserine) Ca2+ and 25 mol% (to the phospholipids) of diolein, stearoylarachidonoylglycerol, or oleoylacetylglycerol. 4) Lateral phase separation of the bilayers on the regions of different fluidities was induced by dipalmitin. These physicochemical effects were correlated with the effects of these DAGs and Ca2+ on the activity of protein kinase C. The increased tendency to form nonbilayer lipid phases and the transverse bilayer perturbations correlated with the increased protein kinase C activity, whereas the actual presence of the nonbilayer lipid phases, as well as the separation of the phosphatidylcholine and phosphatidylserine components, was associated with the decrease in the protein kinase C activity. The lateral phase separation of the bilayer on gel-like and liquid crystalline regions did not have an effect on the activity of the enzyme. These results demonstrate the importance of the physicochemical properties of the membranes in the process of activation of protein kinase C.

The thoracic vent. Clinical experience with a new device for treating simple pneumothorax.

We report recent experience with a new device, the thoracic vent, in the management of simple pneumothorax. There were 16 patients aged 19 to 73 years who suffered pneumothorax due to spontaneous (4), traumatic (3), or iatrogenic (9) causes. Ease of insertion, patient tolerance, and the presence of a unique signal diaphragm all contributed to patient and physician acceptance of the device. Average time to pneumothorax resolution was 2.5 days, and time to thoracic vent removal averaged 3.2 days. There were no immediate recurrences or significant complications. We conclude that the thoracic vent is an effective device for initial and definitive therapy of simple pneumothorax.

Comparison of serum CA 19-9 and CEA levels in a population at high risk for colorectal cancer.

The sera of 563 patients who underwent colonoscopy were assayed for glycolipid antigen CA 19-9 and CEA. These patients represented a broad spectrum of clinical diseases ranging from advanced metastatic cancer of the colon, pancreas, or stomach to those with negative colonoscopic examination. Sensitivity and specificity for CA 19-9 and CEA were calculated using the following clinical definitions. Malignant or pre-malignant disease was defined as colon, pancreatic or stomach carcinoma, stomach dysplasia, atypical adenomatous polyp, atypical villous adenoma, carcinoma in situ and carcinoma in an adenomatous polyp. When the normal group included patients with adenomatous polyp, hyperplastic adenoma, inflammatory disease and patients with no disease apparent, the sensitivity and specificity for CA 19-9 was 23% and 96%, and for CEA, 23% and 95%, respectively. When adenomatous polyp patients were placed in the malignant or pre-malignant disease group, the sensitivity and specificity for CA 19-9 was 8% and 96%, and for CEA, 11% and 95%, respectively. When comparing CA 19-9 and CEA in colorectal carcinoma, the percent positivity of the CEA assay was equal to, or better than, CA 19-9 in all Dukes' stages. In pancreatic carcinomas CA 19-9 showed better diagnostic performance than CEA.

"Bad law" argument in Morgentaler v. The Queen.

The issues raised by the Crown on appeal in Morgentaler v. The Queen from the acquittal of the accused were rendered moot when the Supreme Court of Canada declared the abortion statute (section 251 of the Criminal Code) to be unconstitutional. There was no need for the Court to discuss either the issue of the use of the "defence of necessity" or defence counsel's "bad law" argument. Nevertheless, Chief Justice Dickson found the "bad law" argument of defence counsel, Morris Manning, Q.C., "so troubling," he felt "compelled to comment" on it. Mr. Manning argued that, although the jury was to take its instructions in the law from the judge, it had a right not to apply the law in the case to the facts because the abortion statute was "bad law." In his decision, Chief Justice Dickson reiterated that it is the duty of the judge to instruct the jury in the law and the function of the jury to apply the facts to the law, and that Mr. Manning was wrong to tell the jury otherwise. Among other things, the Chief Justice used a "racist jury" example to demonstrate Mr. Manning's error. The author argues in this comment that the Chief Justice's example was ill-conceived and inapposite, and concludes that the jury and Mr. Manning should be commended for helping to rid Canada of an oppressive abortion law.

Detection of a circulating gastrointestinal cancer antigen in sera of patients with gastrointestinal malignancies by a double determinant immunoassay with monoclonal antibodies against human blood group determinants.

Monoclonal antibodies (MoAbs) produced against determinants A and B of the human ABO blood group system and against the Lea and Leb determinants of the Lewis (Le) blood group system detected these determinants on molecules released by cultured cells of human colorectal, gastric and/or pancreatic carcinoma (Ca) but not by a variety of other cells maintained in culture. Circulating Le antigen could be demonstrated in sera of patients by inhibiting the binding of MoAbs to a target preparation. A double determinant radioimmunoassay (DDIA) was then developed to detect the association of blood group determinants with a previously defined gastrointestinal cancer antigen (GICA). The DDIA with the anti-blood group and anti-GICA antibody was in some cases more sensitive in detecting GICA in sera than using the anti-GICA MoAb alone. Of 55 sera from patients with primary and early recurrent colorectal carcinoma (CRC), 10 (18%) were scored positive in the DDIA using only anti-GICA MoAb. When MoAb binding to a determinant on Leb and on H, type I, was used as first antibody in DDIA followed by anti-GICA MoAb 11 additional sera were reactive, increasing the percentage of positive sera to 38. Using the same combinations of MoAbs, the sensitivity of detection of GICA was only slightly improved from 63 to 66% in sera of patients with advanced CRC. The number of false positive sera from patients with non-malignant gastrointestinal diseases or from healthy donors remained at low levels when anti-blood group determinant antibodies were used together with anti-GICA MoAb. The results indicate that DDIAs with MoAbs against different blood group determinants and tumour associated antigens can improve the detection of circulating antigens in patients with early stage cancer.

The effects of embolectomy-thrombectomy catheters on vascular architecture.

The purpose of this report is to describe the evolution of an embolectomy-thrombectomy catheter (ETC) injury over a six week period. Carotid arteries and jugular veins in six adult dogs were subjected to ETC withdrawals at a standard velocity and balloon size. Vascular segments were excised as early as one hour and as late as six weeks. The specimens were prepared for light, scanning electron and transmission electron microscopic examination. In early specimens, arteries and veins showed endothelial denudation followed by regeneration. In later specimens, the arteries showed progressive disruption of the internal elastic lamina and marked subendothelial proliferation (arteriosclerosis). By the sixth week the artery's intima was equal in thickness to the media. The veins showed only regenerating endothelium without alterations of the subendothelium. Exposure of canine vasculature to ETC procedures caused pronounced transmural damage in the arteries and only endothelial alterations in the veins.

A gas chromatographic--mass spectrometric study of profiles of volatile metabolites in hepatic encephalopathy.

Volatile organic substances present in blood plasma and cerebrospinal fluids of certain control groups of human subjects and cirrhotic patients some of whom were suffering from hepatic encephalopathy were quantitatively analysed and identified. A rapid, reproducible, direct injection capillary column gas chromatographic method was developed for the concentration and detection of such volatiles at mg/l and lower concentrations. Of at least forty volatiles detected, twenty-one were identified. The mean concentration of one of these, 3-methylbutanal, was found to be significantly elevated (p less than 0.01) in chronic encephalopathics (2.37 +/- 0.79 mg/l, n = 18), when compared to the controls (0.30 +/- 0.08 mg/l, n = 20). Furthermore, the concentration of this component increased with the clinically diagnosed severity of the encephalopathic state. The presence of 3-methylbutanal is related to leucine, a branched-chain amino acid linked with hepatic encephalopathy.

The arteriovenous fistula. Its construction in the management of hemophilia.

Arteriovenous fistulae using expanded polytetrafluorethylene (E-PTFE [Gore-Tex]) grafts were constructed in six patients with hemophilia for long-term vascular access where veins had been obliterated. The range of patency was four to 28 months, with a mean of 20 months. All patients had less than 8% level of factor VIII, which may have contributed to fistula patency. This approach was helpful in the management of these patients' conditions.