Early decompressive hemicraniectomy in fulminant herpes simplex encephalitis

Herpes encephalitis can be a life-threatening condition, despite early instauration of acyclovir treatment. In particular patients may succumb to rapidly progressive cerebral oedema. We report a 66-year patient with a Glasgow Coma Score (GCS) of 6 and incipient uncus herniation of the right temporal lobe on the third day. Decompressive hemicraniectomy was immediately performed. The long-term outcome was satisfactory with unassisted gait and a Barthel Index score of 70 after 9 months.

Decreased hephaestin expression and activity leads to decreased iron efflux from differentiated Caco2 cells

Iron is transported across intestinal brush border cells into the circulation in at least two distinct steps. Iron can enter the enterocyte via the apical surface through several paths. However, iron egress from the basolateral side of enterocytes converges on a single export pathway requiring the iron transporter, ferroportin1, and hephaestin, a ferroxidase. Copper deficiency leads to reduced hephaestin protein expression and activity in mouse enterocytes and intestinal cell lines. We tested the effect of copper deficiency on differentiated Caco2 cells grown in transwells and found decreased hephaestin protein expression and activity as well as reduced ferroportin1 protein levels. Furthermore, the decrease in hephaestin levels correlates with a decrease of (55)Fe release from the basolateral side of Caco2 cells. Presence of ceruloplasmin, apo-transferrin or holo-transferrin did not significantly alter the results observed. Repletion of copper in Caco2 cells leads to reconstitution of hephaestin protein expression, activity, and transepithelial iron transport.

Early decompressive hemicraniectomy in fulminant herpes simplex encephalitis

Herpes encephalitis can be a life-threatening condition, despite early instauration of acyclovir treatment. In particular patients may succumb to rapidly progressive cerebral oedema. We report a 66-year patient with a Glasgow Coma Score (GCS) of 6 and incipient uncus herniation of the right temporal lobe on the third day. Decompressive hemicraniectomy was immediately performed. The long-term outcome was satisfactory with unassisted gait and a Barthel Index score of 70 after 9 months.

The role of Notch3 signaling pathway in pancreatic cancer

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Background: Given the extremely poor prognosis of patients diagnosed with pancreatic cancer, identifying new targets for therapeutic intervention is crucial in improving clinical outcome. Existing data support a role for Notch3 pathway in human cancer, pancreas cancer in specific and in normal pancreas development. Method: We developed a pancreatic tissue array. An antibody targeting the extracellular domain of Notch3 was used to evaluate expression levels, grading from 0 to 4+ to determine the prevalence of Notch3 in pancreatic cancer. Notch3 expression was used to correlate with clinical data (IRB approved). Using small interfering RNA (siRNA) we tested the downstream effects of Notch3 in pancreatic cancer cell line BxP3 in vitro. Furthermore, to study pharmacologic inhibition of Notch3 processing and activation we exposed Panc-1, HPAF II and BxP3 pancreas cancer cell lines to γ-secretase inhibitors (previously demonstrated to block upstream of Notch3 thereby inhibiting Notch3). Results: Strong staining (+2 or greater) for Notch3 was seen in 50 of 72 (69%) resected specimens. No correlation with survival or tumor grade was seen. Using siRNA, we demonstrated that inhibiting Notch3 downregulated the antiapoptotic protein Bcl-xL but not Bcl-2. When γ-secretase inhibitors (GSI and L-685,458) were used, the previously mentioned pancreatic cell lines demonstrated reduction in proliferation rates. Conclusion: Notch3 overexpression is common in pancreas cancer. While Notch 3 expression does not clearly correlate with survival, our in vitro data suggest that Notch3 affects apoptotic pathways and may represent a potential target for intervention in patients with pancreatic cancer.

No significant financial relationships to disclose.

Single Agent Irinotecan for the Treatment of Metastatic or Recurrent Squamous Carcinoma of the Head and Neck (SCCHN)

Background

Patients with recurrent or metastatic head and neck cancer (HNC) have a poor response and survival with currently available chemotherapy agents. Thus new agents are needed. We report the results of a phase II trial of irinotecan in patients with metastatic or recurrent HNC.

Patients and Methods

Chemonaive patients were treated with irinotecan 125 mg/m2 on a weekly schedule for four weeks, followed by a two week rest. However, due to excessive toxicity, the dose and schedule of irinotecan was changed to 75 mg/m2 on days 1 and 8 of a 21 day cycle. All previously treated patients received 75 mg/m2 on days 1 and 8 of a 21 day cycle.

Results

Forty-nine patients were enrolled on study. The response rate was 20% in the chemonaive patients treated at the 125 mg/m2 dose. The response rate decreased to 12.5% at the 75 mg/m2 dose. In the previously treated cohort, the response rate was 20%. Median survival for the chemonaive and previously treated cohorts were 6.7 months and 5.0 months, respectively.

Conclusions

Irinotecan has modest activity in chemonaive and previously treated HNC, thus it merits further study in this advanced disease population.

EEG and the variance of motor evoked potential amplitude

The motor threshold is an important parameter in selecting the treatment intensity of patients undergoing transcranial magnetic stimulation. The large variance in magnitude of motor evoked responses has forced clinicians to perform many trials and average the results to find a repeatable value for motor threshold. Our objective is to investigate the source of the variance in amplitude. Four clinically healthy adult males participated in an EEG and EMG during transcranial magnetic stimulation of the left motor cortex, 100% motor threshold, 0.1 Hz. Per our hypothesis, a significant negative correlation of .22 was found between the amplitude of the motor evoked potential and the power in the high alpha frequency band during the pre-stimulus period (p < .001). In addition, a significant positive correlation of .17 was found between the motor evoked potential (MEP) amplitude and the gamma band (p < .001). The strongest correlation of .27 (p < .001) was found between the MEP amplitude and the ratio of the power in the low gamma to high alpha band. We conclude that the gamma to alpha power ratio may be a useful indicator of cortical excitability.

IFN-gamma-dependent and -independent initiation of switch recombination by NK cells

We have examined the effect of IL-2-propagated NK or NK-T cells on each of the steps required for B cell switch recombination leading to IgG2a production. The results indicate that NK cells, on their own and in the absence of IFN-gamma, can induce germline transcription in resting, IgG(-) B lymphocytes from the gamma2a locus as well as mRNA for activation-induced cytidine deaminase (AID) via a process that requires cell-cell interactions. The results also show that, in contrast to induction by T cells, activation by NK cells does not involve CD40-CD40 ligand interactions and does not extend to the induction of Igamma1 transcription. Furthermore, in contrast to stimulation by LPS and IFN-gamma or by T cells, the activation events initiated by NK cells do not result in significant synthesis of functional gamma2a mRNA in resting B lymphocytes even in the presence of IFN-gamma. Thus, induction of germline and AID transcripts are necessary but not sufficient events for functional switching to IgG2a. These experiments, showing that NK cells themselves cannot induce IgG2a production but can polyclonally program B lymphocytes so that they preferentially switch to this isotype may explain how activated NK cells can skew the Ag-specific immune response toward IgG2a. The findings also provide further demonstration of the definitive yet limited extent of how a non-Ag-specific component of the innate system can modulate the direction of the adaptive immune response.

Inappropriate expression of IgD from a transgene inhibits the function of antigen-specific memory B cells

IgD expression has been shown to be downmodulated upon mitogenic or antigenic activation of B cells. To investigate whether this decrease is of functional significance we studied a mouse strain that expresses transgenic IgD on all B cells. The rearranged gene encoding the heavy chain of this IgD requires endogenous gene rearrangement before it can be expressed; therefore, normal B cell development is not affected. As a result, both transgenic IgD and endogenous IgM and IgD are expressed on all peripheral B cells. We show that the presence of extraneous IgD does not affect normal B cell activation by polyclonal stimulators, nor does it affect the primary IgM or IgG responses to TI or TD antigens. However, the secondary memory response is significantly diminished. The decrease is not attributable to a defective generation of memory B cells; instead the activation of memory cells appears to be compromised. Since the depressed response can be overcome by prior aggregation of the transgenic IgD with allotype-specific anti-IgD antibodies, it appears that persistence of the transgenic IgD on memory cells may influence their ability to be activated. Thus, the decrease in IgD expression on normal B cells after activation may be necessary for optimal activation of memory cells.

Development and evaluation of an epidural injection simulator with force feedback for medical training

Performing epidural injections is a complex task that demands a high level of skill and precision from the physician, since an improperly performed procedure can result in serious complications for the patient. The objective of our project is to create an epidural injection simulator for medical training and education that provides the user with realistic feel encountered during an actual procedure. We have used a Phantom haptic interface by SensAble Technologies, which is capable of three-dimensional force feedback, to simulate interactions between the needle and bones or tissues. An additional degree-of-freedom through an actual syringe was incorporated to simulate the "loss of resistance" effect, commonly considered to be the most reliable method for identifying the epidural space during an injection procedure. The simulator also includes a new training feature called "Haptic Guidance" that allows the user to follow a previously recorded expert procedure and feel the encountered forces. Evaluations of the simulator by experienced professionals indicate that the simulation system has considerable potential to become a useful aid in medical training.

Immunohistochemical evidence for the Na+/Ca2+ exchanger in squid olfactory neurons

The olfactory organs from the squid Lolliguncula brevis are composed of a pseudostratified epithelium containing five morphological subtypes of chemosensory neurons and ciliated support cells. Physiological recordings have been made from two of the subtypes and only the type 4 neuron has been studied in detail. Odour-stimulated increases in intracellular calcium and rapid activation of an electrogenic Na+/Ca2+ exchanger current in type 4 neurons suggest that the exchanger proteins are localized very close to the transduction machinery. Electrophysiological studies have shown that olfactory signal transduction takes place in the apical ciliary regions of olfactory neurons. Using polyclonal antiserum against squid Na+/Ca2+ proteins, we observed specific staining in the ciliary region of cells that resemble type 2, 3, 4 and 5 neurons. Staining was also observed in axon bundles, and in muscle tissue. Collectively, these data support the model that Na+/Ca2+ exchanger proteins are localized to transduction machinery in cilia of type 4 neurons and suggest that the other olfactory subtypes also use Ca2+ during chemosensory responses.

Site-directed mutagenesis of squalene-hopene cyclase: altered substrate specificity and product distribution

BACKGROUND

Two regions of squalene-hopene cyclase (SHC) were examined to define roles for motifs posited to be responsible for initiation and termination of the enzyme-catalyzed polyolefinic cyclizations. Specifically, we first examined the triple mutant of the DDTAVV motif, a region deeply buried in the catalytic cavity and thought to be responsible for the initiation of squalene cyclization. Next, four mutants were prepared for Glu45, a residue close to the substrate entrance channel proposed to be involved in the termination of the cyclization of squalene.

RESULTS

The DDTAVV motif in SHC was changed to DCTAEA, the corresponding conserved region of eukaryotic oxidosqualene cyclase (OSC), by the triple mutation of D377C/V380E/V381A; selected single mutants were also examined. The triple mutant showed no detectable cyclization of squalene, but effectively cyclized 2,3-oxidosqualene to give mono- and pentacyclic triterpene products. Of the Glu45 mutants, E45A and E45D showed reduced activity, E45Q showed slightly increased activity, and E45K was inactive. A normal yield of pentacyclic products was produced, but the ratio of hopene 2 to hopanol 3 was significantly changed in the less active mutants.

CONCLUSIONS

Initiation and substrate selectivity may be determined by the interaction of the DDTAVV motif with the isopropylidene of squalene (for SHC) and of the DCTAEA motif with the epoxide of oxidosqualene (for OSC). This is the first report of a substrate switch determined by a central catalytic motif in a triterpenoid cyclase. At the termination of cyclization, the product ratio may be largely controlled by Glu45 at the entrance channel to the active site.

Adenovirus-mediated combination suicide and cytokine gene therapy for bladder cancer

BACKGROUND

The present study tests the hypothesis that adenovirus-mediated transfer of murine IL-2 (ADV/RSV-mIL-2) alone or in combination with HSV-tk + GCV will improve antitumorigenic response in the murine MBT-2 model.

MATERIALS AND METHODS

mIL-2 production and toxicity were determined in vitro using an ELISA and a cell proliferation assay. Tumor-bearing animals were randomly assigned into four treatment groups and directly injected with combinations of ADV/RSV-tk and ADV/RSV-mIL-2. In a separate experiment, the above-mentioned groups were followed by two subsequent treatments with ADV/RSV-mIL-2.

RESULTS

Transduced MBT-2 cells were able to express mIL-2 in a time and dose dependent fashion. We could not demonstrate any improvement in antitumorigenic response with mIL-2 gene therapy alone or in combination with HSV-tk-suicide gene therapy over HSV-tk suicide gene therapy alone.

CONCLUSIONS

Although ADV/RSV-mIL-2 transduced MBT-2 cells were able to produce large amounts of mIL-2 in vitro, we could not demonstrate significant tumor growth inhibition by adding mIL-2 gene therapy to suicide gene therapy. The growth inhibitory effects of sequential suicide and cytokine gene therapy were transient and not superior to single dose suicide and cytokine gene therapy.

Characterization of ripening-regulated cDNAs and their expression in ethylene-suppressed charentais melon fruit

Charentais melons (Cucumis melo cv Reticulatus) are climacteric and undergo extremely rapid ripening. Sixteen cDNAs corresponding to mRNAs whose abundance is ripening regulated were isolated to characterize the changes in gene expression that accompany this very rapid ripening process. Sequence comparisons indicated that eight of these cDNA clones encoded proteins that have been previously characterized, with one corresponding to ACC (1-aminocyclopropane-1-carboxylic acid) oxidase, three to proteins associated with pathogen responses, two to proteins involved in sulfur amino acid biosynthesis, and two having significant homology to a seed storage protein or a yeast secretory protein. The remaining eight cDNA sequences did not reveal significant sequence similarities to previously characterized proteins. The majority of the 16 ripening-regulated cDNAs corresponded to mRNAs that were fruit specific, although three were expressed at low levels in vegetative tissues. When examined in transgenic antisense ACC oxidase melon fruit, three distinct patterns of mRNA accumulation were observed. One group of cDNAs corresponded to mRNAs whose abundance was reduced in transgenic fruit but inducible by ethylene treatment, indicating that these genes are directly regulated by ethylene. A second group of mRNAs was not significantly altered in the transgenic fruit and was unaffected by treatment with ethylene, indicating that these genes are regulated by ethylene-independent developmental cues. The third and largest group of cDNAs showed an unexpected pattern of expression, with levels of mRNA reduced in transgenic fruit and remaining low after exposure to ethylene. Regulation of this third group of genes thus appears to ethylene independent, but may be regulated by developmental cues that require ethylene at a certain stage in fruit development. The results confirm that both ethylene-dependent and ethylene-independent pathways of gene regulation coexist in climacteric fruit.

The binding site for an inhibitor of squalene:hopene cyclase determined using photoaffinity labeling and molecular modeling

BACKGROUND

The squalene:hopene cyclases (SHCs) are bacterial enzymes that convert squalene into hopanoids, a function analogous to the action of oxidosqualene cyclases (OSCs) in eukaryotic steroid and triterpenoid biosynthesis. We have identified the binding site for a selective, potent, photoactivatable inhibitor of an SHC.

RESULTS

SHC from Alicyclobacillus acidocaldarius was specifically labeled by [3H]Ro48-8071, a benzophenone-containing hypocholesteremic drug. Edman degradation of a peptide fragment of covalently modified SHC confirmed that Ala44 was specifically modified. Molecular modeling, using X-ray-derived protein coordinates and a single point constraint for the inhibitor, suggested several geometries by which Ro48-8071 could occupy the active site.

CONCLUSIONS

A covalent complex of a potent inhibitor with a squalene cyclase has been characterized. The amino acid modification and molecular modeling suggest that Ro48-8071 binds at the junction between the central cavity and substrate entry channel, therefore inhibiting access of the substrate to the active site.

On the control of oocyte meiotic maturation and ovulation in Caenorhabditis elegans

Prior to fertilization, oocytes undergo meiotic maturation (cell cycle progression) and ovulation (expulsion from the ovary). To begin the study of these processes in Caenorhabditis elegans, we have defined a time line of germline and somatic events by video microscopy. As the oocyte matures, its nuclear envelope breaks down and its cell cortex rearranges. Immediately thereafter, the oocyte is ovulated by increasing contraction of the myoepithelial gonadal sheath and relaxation of the distal spermatheca. By systematically altering the germ cell contents of the hermaphrodite using mutant strains, we have uncovered evidence of four cell-cell interactions that regulate maturation and ovulation. (1) Both spermatids and spermatozoa induce oocyte maturation. In animals with a feminized germline, maturation is inhibited and oocytes arrest in diakinesis. The introduction of sperm by mating restores maturation. (2) Sperm also directly promote sheath contraction. In animals with a feminized or tumorous germline, contractions are infrequent, whereas in animals with a masculinized germline or with sperm introduced by mating, contractions are frequent. (3 and 4) The maturing oocyte both induces spermathecal dilation and modulates sheath contractions at ovulation; dilation of the distal spermatheca and sharp increases in sheath contraction rates are only observed in the presence of a maturing oocyte.

Synthesis and biological activity of a novel methylamine-bridged enkephalin analogue (MABE): a new route to cyclic peptides and peptidomimetics

The synthesis and biological activity of a methylamine-bridged enkephalin analogue (MABE) is presented. The key step in the synthesis of the target compound involves the ring opening of Cbz-d-serine beta-lactone with Boc-Phe-NHCH2CH2NHCH3. Further synthetic elaboration of the resulting building block yielded compound 1 (MABE, Tyr-c[(NbetaCH3)-D-A2pr-Gly-Phe-NHCH2CH2-], where A2pr is a 2,3-diaminopropionic acid residue). Utilizing a combination of NMR and molecular modeling, the structure-biological activity relationships for compound 1 were studied. Using an in vitro isolated receptor assay, MABE was found to have affinities for isolated mu delta, and kappa opioid receptors of 1.6, 2.1, and 340 nM, respectively. By an in vivo thermal escape assay, MABE was found to have an ED50 of 0.027 microg in the rat when administered intrathecally. This effect was reversed by naloxone. By comparison, DAMGO, morphine, and DPDPE were found to yield ED50 values of 0.14, 2.4, and 54 microg, respectively, in the same assay.