Cell-type and subcellular compartment-specific APEX2 proximity labeling reveals activity-dependent nuclear proteome dynamics in the striatum

The vertebrate brain consists of diverse neuronal types, classified by distinct anatomy and function, along with divergent transcriptomes and proteomes. Defining the cell-type specific neuroproteomes is important for understanding the development and functional organization of neural circuits. This task remains challenging in complex tissue, due to suboptimal protein isolation techniques that often result in loss of cell-type specific information and incomplete capture of subcellular compartments. Here, we develop a genetically targeted proximity labeling approach to identify cell-type specific subcellular proteomes in the mouse brain, confirmed by imaging, electron microscopy, and mass spectrometry. We virally express subcellular-localized APEX2 to map the proteome of direct and indirect pathway spiny projection neurons in the striatum. The workflow provides sufficient depth to uncover changes in the proteome of striatal neurons following chemogenetic activation of Gα_q-coupled signaling cascades. This method enables flexible, cell-type specific quantitative profiling of subcellular proteome snapshots in the mouse brain.

Mapping neuronal proteomes with genetic, subcellular, and temporal specificity is a challenging task. This study uncovers proteome dynamics in two classes of striatal spiny projection neurons in the mouse brain using a genetically targeted APEX2-based proximity labeling approach.

[Lidocaine in oncological surgery: the role of blocking in voltage-gated sodium channels. A narrative review]

BACKGROUND

The current evidence suggests that oncological surgery, which is a therapy used in the treatment of solid tumors, increases the risk of metastasis. In this regard, a wide range of tumor cells express Voltage-Gated Sodium Channels (VGSC), whose biological roles are not related to the generation of action potentials. In epithelial tumor cells, VGSC are part of cellular structures named invadopodia, involved in cell proliferation, migration, and metastasis. Recent studies showed that lidocaine could decrease cancer recurrence through its direct effects on tumor cells and immunomodulatory properties on the stress response.

OBJECTIVE

The aim of this narrative review is to highlight the role of VGSC in tumor cells, and to describe the potential antiproliferative effect of lidocaine during the pathogenesis of metastasis.

CONTENTS

A critical review of literature from April 2017 to April 2019 was performed. Articles found on PubMed (2000-2019) were considered. A free text and MeSH-lidocaine; voltage-gated sodium channels; tumor cells; invadopodia; surgical stress; cell proliferation; metastasis; cancer recurrence-for articles in English, Spanish and Portuguese language-was used. A total of 62 were selected.

CONCLUSION

In animal studies, lidocaine acts by blocking VGSC and other receptors, decreasing migration, invasion, and metastasis. These studies need to be replicated in humans in the context of oncological surgery.

Lidocaine in oncological surgery

Background

The current evidence suggests that oncological surgery, which is a therapy used in the treatment of solid tumors, increases the risk of metastasis. In this regard, a wide range of tumor cells express Voltage-Gated Sodium Channels (VGSC), whose biological roles are not related to the generation of action potentials. In epithelial tumor cells, VGSC are part of cellular structures named invadopodia, involved in cell proliferation, migration, and metastasis. Recent studies showed that lidocaine could decrease cancer recurrence through its direct effects on tumor cells and immunomodulatory properties on the stress response.

Objective

The aim of this narrative review is to highlight the role of VGSC in tumor cells, and to describe the potential antiproliferative effect of lidocaine during the pathogenesis of metastasis.

Contents

A critical review of literature from April 2017 to April 2019 was performed. Articles found on PubMed (2000–2019) were considered. A free text and MeSH-lidocaine; voltage-gated sodium channels; tumor cells; invadopodia; surgical stress; cell proliferation; metastasis; cancer recurrence – for articles in English, Spanish and Portuguese language – was used. A total of 62 were selected.

Conclusion

In animal studies, lidocaine acts by blocking VGSC and other receptors, decreasing migration, invasion, and metastasis. These studies need to be replicated in humans in the context of oncological surgery.

Anesthesia Options and the Recurrence of Cancer: What We Know so Far?

Surgery is a critical period in the survival of patients with cancer. While resective surgery of primary tumors has shown to prolong the life of these patients, it can also promote mechanisms associated with metastatic progression. During surgery, patients require general and sometimes local anesthetics that also modulate mechanisms that can favor or reduce metastasis. In this narrative review, we summarized the evidence about the impact of local, regional and general anesthesia on metastatic mechanisms and the survival of patients. The available evidence suggests that cancer recurrence is not significantly impacted by neither regional anesthesia nor volatile or total intravenous anesthesia.

The 1918-1920 influenza pandemic in Peru

BACKGROUND

Increasing our knowledge of past influenza pandemic patterns in different regions of the world is crucial to guide preparedness plans against future influenza pandemics. Here, we undertook extensive archival collection efforts from three representative cities of Peru-Lima in the central coast, Iquitos in the northeastern Amazon region, Ica in the southern coast-to characterize the temporal, age and geographic patterns of the 1918-1920 influenza pandemic in this country.

MATERIALS AND METHODS

We analyzed historical documents describing the 1918-1920 influenza pandemic in Peru and retrieved individual mortality records from local provincial archives for quantitative analysis. We applied seasonal excess mortality models to daily and monthly respiratory mortality rates for 1917-1920 and quantified transmissibility estimates based on the daily growth rate in respiratory deaths.

RESULTS

A total of 52,739 individual mortality records were inspected from local provincial archives. We found evidence for an initial mild pandemic wave during July-September 1918 in Lima, identified a synchronized severe pandemic wave of respiratory mortality in all three locations during November 1918-February 1919, and a severe pandemic wave during January 1920-March 1920 in Lima and July-October 1920 in Ica. There was no recrudescent pandemic wave in 1920 in Iquitos. Remarkably, Lima experienced the brunt of the 1918-1920 excess mortality impact during the 1920 recrudescent wave, with all age groups experiencing an increase in all cause excess mortality from 1918-1919 to 1920. Middle age groups experienced the highest excess mortality impact, relative to baseline levels, in the 1918-1919 and 1920 pandemic waves. Cumulative excess mortality rates for the 1918-1920 pandemic period were higher in Iquitos (2.9%) than Lima (1.6%). The mean reproduction number for Lima was estimated in the range 1.3-1.5.

CONCLUSIONS

We identified synchronized pandemic waves of intense excess respiratory mortality during November 1918-February 1919 in Lima, Iquitos, Ica, followed by asynchronous recrudescent waves in 1920. Cumulative data from quantitative studies of the 1918 influenza pandemic in Latin American settings have confirmed the high mortality impact associated with this pandemic. Further historical studies in lesser studied regions of Latin America, Africa, and Asia are warranted for a full understanding of the global impact of the 1918 pandemic virus.

Immunohistochemically proven cytomegalovirus end-organ disease in solid organ transplant patients: clinical features and usefulness of conventional diagnostic tests

We studied the main clinical features, outcome, and laboratory parameters in a group of solid organ transplant (SOT) patients with immunohistochemically proven cytomegalovirus (CMV) disease. Confirmed CMV cases were obtained through databases. Demographics, clinical data, transplantation type, immunosuppressive regimens, donor and recipient CMV serostatus, therapy, outcome and laboratory results, pp65 antigenemia, and qualitative polymerase chain reaction (PCR) for CMV were analyzed. From 1995 to 2004, 31 cases with complete medical records were identified. Disease appeared between 24 and 2538 days after transplantation but most cases presented in the first 100 days. Gastrointestinal CMV disease was the most frequent form (71%), while thrombocytopenia was present in 50% of cases, and leukopenia was less common (35.5%). CMV pp65 antigenemia was positive in 58% of patients, but its sensitivity increased to 71% if performed during the first 6 months. A qualitative CMV PCR technique gave similar results during this period (71.4%). Most patients were treated with intravenous ganciclovir (n=25; 80.6%). In 4 cases (19.4%), use of foscarnet alone or a sequential regimen with ganciclovir-foscarnet was deemed necessary. Surgical procedures were necessary in 5 patients (16%). The death rate reached 13%. CMV end-organ disease can be a life-threatening infection in SOT patients. Gastrointestinal disease was the most frequent end-organ disease. CMV antigen detection is best suited for the early period after transplantation.

Analysis of nucleotide diversity of NAT2 coding region reveals homogeneity across Native American populations and high intra-population diversity

N-acetyltransferase 2 (NAT2), an important enzyme in clinical pharmacology, metabolizes antibiotics such as isoniazid and sulfamethoxazole, and catalyzes the transformation of aromatic and heterocyclic amines from the environment and diet into carcinogenic intermediates. Polymorphisms in NAT2 account for variability in the acetylator phenotype and the pharmacokinetics of metabolized drugs. Native Americans, settled in rural areas and large cities of Latin America, are under-represented in pharmacogenetics studies; therefore, we sequenced the coding region of NAT2 in 456 chromosomes from 13 populations from the Americas, and two from Siberia, detecting nine substitutions and 11 haplotypes. Variants *4 (37%), *5B (23%) and *7B (24%) showed high frequencies. Average frequencies of fast, intermediate and slow acetylators across Native Americans were 18, 56 and 25%, respectively. NAT2 intra-population genetic diversity for Native Americans is higher than East Asians and similar to the rest of the world, and NAT2 variants are homogeneously distributed across native populations of the continent.

Bacteremia and septic shock after solid-organ transplantation

BACKGROUND

Bacteremia and septic shock remain important causes of morbidity and mortality after solid-organ transplantation. The aim of this study was to assess the characteristics and risk factors for mortality among patients with bloodstream infections and shock.

METHODS

From January 1991 to December 2000, all episodes of bloodstream infection were prospectively examined, considering bacteremia or fungemia as significant according to the CDC criteria. Septic shock was diagnosed in a patient with systemic inflammatory response syndrome and persistent dysfunction of at least one organ caused by hypoperfusion despite hemodynamic support.

RESULTS

There were 466 episodes of bacteremia in 382 patients, with 66 of them developing septic shock. Risk factors for developing shock were age >50 (P = .006), liver transplant (P = .029), nosocomial infection (P = .034), pulmonary focus (P = .0001), P. aeruginosa infection (P = .001), and polymicrobial etiology (P = .039). On multivariate analysis, only age, nosocomial infection, and pulmonary source were significant. Among 66 shock patients, bacteremia was due to gram-negative bacteria in 53%, gram-positive bacteria in 24%, fungal in 7.5%, and polymicrobial in 12% of patients. The most frequent source was the lung (26%). Empiric antimicrobial therapy was correctly chosen in 79%; however, 36 patients died (54%), including 27 despite correct therapy. Urinary tract infections had less mortality than other foci.

CONCLUSIONS

Risk factors for developing septic shock in bacteremia were age more than 50 years, nosocomial acquisition, and pulmonary focus. Despite adequate empiric antibiotic therapy, the mortality remained high.

Removal of chromium hexavalent from rinsing chromating waters electrochemical reduction in a laboratory pilot plant

In this work, experiments in a 16 L operating volume laboratory pilot plant with ring iron rotary electrodes were performed, obtaining an overall kinetic equation rate of hexavalent chromium reduction concentration and current density-dependent. Other scale-up criteria such as Reynolds' number were also evaluated to ensure a completely stirred reactor at low energy expenditure. A dimensionless N(E) is a relationship between liquid properties and the electric charge supplied to the system. The number, which depends on the rotation iron ring electrode speed number and the current density, is proposed to be used as scale-up criterion. It was found that at N(Re) = 42,179 (130 rpm rotation electrodes rate) and at N(E) = 9.8 x 10(5) (current density of 113 A/m2), complete mixing was reached at minimum energy spent and the process becomes more efficient. In addition, it was found that the higher the current density, the less treatment time and less energy spent on agitation. After the electrochemical treatment the Cr(VI) concentration in the rinsing wastewater was less than 0.5 mg/L.

Effect of intermittent hypoxia on cardiovascular function, adrenoceptors and muscarinic receptors in Wistar rats

The usual model of intermittent hypoxia (sleep apnoea) corresponds to repeated episodes of hypoxia from a few seconds to a few hours interspersed with episodes of normoxia. The aim of this study was to evaluate in rats the effect of two periods of intermittent exposure for 2 months to hypoxia (IHX1, 24 h in hypoxia (428 Torr), 24 h in normoxia; IHX2, 48 h in hypoxia (428 Torr), 24 h in normoxia) as a new model of hypoxia simulating intermittent exposure to high altitude experienced by Andean miners. We assessed the haematological parameters, time course of resting heart rate and systolic blood pressure. We also evaluated the expression of adrenergic and muscarinic receptors. IHX1 and IHX2 produced an increase in haematocrit, haemoglobin concentration and mean corpuscular volume as previously seen in most hypoxic models. IHX1 and IHX2 induced a similar sustained elevation of systolic blood pressure (132 +/- 2 and 135 +/- 3 mmHg, respectively, vs. the control level of 121 +/- 16 mmHg) after 10 days of exposure without change in heart rate. Right ventricular (RV) hypertrophy (225 +/- 13 and 268 +/- 15 mg g(-1), vs. 178 +/- 7 mg g(-1) and downregulation of alpha1-adrenoceptor (RV: 127 +/- 21 and 94 +/- 16 fmol mg(-1) vs. 157 +/- 8 fmol mg(-1); left ventricle (LV): 141 +/- 5 and 126 +/- 9 fmol mg(-1) vs. 152 +/- 5 fmol mg(-1)) have been found in both groups, with right ventricular hypertrophy being greater and alpha1-adrenoceptor density being lower in IHX2 than in HX1 groups. These data indicate that both parameters are related to the time of exposure to hypoxia. IHX1 and IHX2 produced the same magnitude of upregulation of muscarinic receptors (LV, 60%; RV, 40%), and no change in beta-adrenoceptors. In conclusion, exposure to intermittent hypoxia led to polycythaemia and RV hypertrophy as observed in other types of hypoxia. A specific cardiovascular response was seen, that is an increase in blood pressure without change in heart rate, which was different from the one observed in episodic and chronic hypoxia. Furthermore, this model involved specific modifications of alpha1-adrenergic and muscarinic expression.

[Pediatric lung resection. A case series and evaluation of postoperative lung function]

The most common causes of pulmonary lobectomy in children are congenital lung malformations (CLM) and bronchiectasias. Our aim was to present the causes and clinical course and lung function of lobectomized patients. Between 1990 and July 1999 27 lobectomies were performed on patients whose ages ranged from newborn to 14 years. Lobectomies were performed to correct CLM in 124 cases and for acquired pulmonary disease (APD) in 13. Among CLM cases, half (n = 7) had cystic adenomatoid malformation. Among the APD patients, 10 had bronchiectasias, with etiological confirmation in 6 cases (3 secondary to serious adenovirus infection). Mean hospital stay was 4.6 days among those who experienced no postoperative complications. Symptoms resolved after surgery for most symptomatic patients. Lung function tests could be carried out with 8 patients over 6 years old whose operations had taken place 7 to 78 months earlier (x = 35 months) and whose age at the time of surgery was a mean 7 years 6 months (range 60 to 144 months). Spirometry showed normal forced vital capacity for 7 of 8 patients (87 to 143% of theoretical value). Arterial oxygen saturation measured during and after a 6-minute walking test was normal for 7 of 8 patients. Chest films showed reduced lung volume on the affected side in 5 of 8 patients. In summary, lobectomy is a procedure with few complications. It requires a short hospital stay and has good postoperative prognosis. Function and x-ray studies show adequate lung growth and development, with normal lung function in those who could be so examined because they were old enough to cooperate.

Ozonation of 1,2-dihydroxybenzene in the presence of activated carbon

This work aims at obtaining experimental data on ozonation of 1,2-dihydroxybenzene (DHB) in the presence of activated carbon, with a view to assessing possible changes in its surface chemical structure and adsorption capacity. Experiments were conducted in a 0.5 L reactor, loaded with 2 g Filtrasorb 400 granular activated carbon, and 1-5 mM DHB aqueous solution at pH 2-8. Ozone gas was generated with an Ozocav generator, and fed into the reactor for a given exposure time, in the range 0.5-240 min, at 25 degrees C and 1 atm. After each run, liquid and activated carbon samples were taken for chemical assays. Soluble organic groups present on the active carbon surface were desorbed and analysed by GC-MS and HPLC. Activated carbon chemical surface properties were analysed using TPD, FT-IR, and XPS techniques. Reactions between ozone and adsorbed DHB were shown to be fast, leading to formation of C-6, C-4 and C-2 by-products. Oxygenated surface groups, particularly, COOH and C = O, increased as a result of ozonation.

Kinetics and toxicity of direct reaction between ozone and 1,2-dihydrobenzene in dilute aqueous solution

The presence of toxic aromatic organic compounds in industrial wastewater affects the efficiency of conventional biological treatment. The oxidizing power of ozone represents an interesting pretreatment to reduce toxicity and increase biodegradability. At low pH, ozone is known to attack electron-rich structures by direct electrophilic reactions which open aromatic rings, and generate smaller oxidized compounds. This paper reports experimental results on kinetic and toxicity aspects of ozone direct reactions with 1,2-dihydrobenzene. This toxic compound is frequently found in cellulose bleaching effluents. Although the reaction pathway is rather complex, 4-carbon compounds, such as maleic acid, are readily formed during the first stage of ozonation. These 4-carbon compounds are further oxidized to form smaller molecules (mostly 2-carbon, such as oxalic acid). The apparent kinetics of 1,2-dihydrobenzene follows a second order law, with a rate constant around 0.36 (dm3 mmol-1s-1), at pH 2 and 20 degrees C. Results show that the BOD:COD ratio increase five-fold as ozonation progresses. Furthermore, the mutagenicity of 1,2-dihydrobenzene totally disappears as the aromatic compound is destroyed by ozonation.

Strategies to enhance the biodegradation of toxic compounds using discontinuous processes

This study presents two strategies used to enhance the biological degradation of phenolic wastewaters. In the first one the operation of a sequencing batch biofilter added with granular activated carbon (SBB-AC) was studied. The second strategy presents the results of the automation of a sequencing batch reactor in order to optimize the reaction phase. In this case, the dissolved oxygen was employed to monitor and control the reactor. The results of the SBB-AC system, based on the configuration of the reactor, type and size of activated carbon and size of the packing material, are discussed. The system biodegraded efficiently (total phenol removals as high as 97%) high concentrations (600 mg/l) of a mixture of phenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol. Maximal eliminated loads of 4.33 kg COD/m3-d were achieved. For the second strategy, the applicability of an optimal control for a SBR using the dissolved oxygen as the measured variable was demonstrated. When the reactor was operated under the time-optimal control strategy, the degradation time of 4-chlorophenol was reduced. A very satisfactory operation of the reactor was observed, since the removal efficiencies were around 99%.

A multicenter, randomized, double-blind clinical trial examining the effect of oral human recombinant epidermal growth factor on the healing of duodenal ulcers

BACKGROUND

Our aim was to study the efficacy of oral human recombinant epidermal growth factor (EGF) in the treatment of duodenal ulcers, on the basis of its repairing actions in the gastrointestinal tract.

METHODS

A placebo-controlled, multicenter, randomized, and double-blind study was conducted. Treatment groups were A) placebo solution, B) 10 microg/ml of human recombinant (hr)-EGF, and C) 50 microg/ml of hr-EGF, three times daily during 6 weeks. Patients, 15-65 years old, with a duodenal ulcer >4 mm, who gave their written informed consent to participate were eligible. Exclusion criteria were gastric ulcer and more than one duodenal ulcer, ulcer-related complications, and previous treatment with oral EGF or other specific anti-ulcer drugs in the previous 2 weeks. The main outcome variable was ulcer healing, evaluated by endoscopy after the 2nd, 4th, and 6th week.

RESULTS

One hundred and three patients were included. The groups were comparable with regard to age, sex, toxic habits, antecedents of ulcerous disease, initial size and depth or the ulcer, initial symptoms, and positivity for Helicobacter pylori. The ulcers were healed in a larger proportion of patients treated with hr-EGF at the highest dose (70.6% in group C versus 40.0% and 35.3% in placebo and low-dose groups, respectively (P = 0.007)). The difference was significant from week 4 on. Groups A and B did not differ. Eighty-eight percent of group C patients were cured or improved versus 57% and 56% in groups A and B, respectively. No adverse reactions were reported.

CONCLUSIONS

Oral hr-EGF was effective in the treatment of duodenal ulcer at a 50-microg/ml dose every 8 h but not at 10 microg/ml.

Stereoselective synthesis of optically active beta-lactams, potential inhibitors of pilus assembly in pathogenic bacteria

[reaction: see text] Optically active beta-lactams 3 are obtained in excellent yields (up to 93%) and with complete stereoselectivity from Meldrum's acid derivatives 1 and Delta(2)-thiazolines 2. A selective reduction to aldehydes 5 (R = Ar or CH(2)Ar) was then accomplished by using DIBAL-H. This rigid framework, with stereochemistry different than that of penicillin, is designed to be a suitable scaffold for the development of compounds inhibiting pilus formation in uropathogenic Escherichia coli.

18S ribosomal DNA-based PCR for diagnosis of Trichomonas vaginalis

Trichomonas vaginalis remains the most common sexually transmitted parasite in the world and is considered a major risk factor in the transmission of the human immunodeficiency virus. A PCR technique using primers targeting a specific region of the 18S rRNA gene of T. vaginalis was developed. The PCR test was standardized using 15 reference strains, giving a single product of 312 bp in all strains. No amplification was observed when DNA from related organisms or human DNA was used as a target. The test was evaluated on 372 vaginal swab specimens and 361 urine samples from women attending infertility and obstetric clinics at two separate hospitals in Lima, Peru. Compared to T. vaginalis culture, the overall sensitivity and specificity of PCR of vaginal swab samples was 100% and 98%, respectively. The PCR of urine samples was 100% sensitive and 99.7% specific compared to culture of vaginal swab, but the sensitivity drops to 83.3% when compared to PCR of vaginal swabs. All culture-positive samples were found to be positive by PCR in either urine or vaginal secretion. None of the PCR-negative samples were positive by culture. The origin of the amplification was confirmed by digestion of PCR products with HaeIII. This PCR assay, which is easy to perform and has a high sensitivity and specificity, should be useful for routine diagnosis of T. vaginalis infection.

[Medical-surgical experience of intestinal intussusception. Experience of a university institution]

BACKGROUND

Management of intestinal intussusception in children has evolved from exclusively surgical treatments to nonoperative reduction under fluoroscopic monitoring.

AIM

To report a 10 year experience in a University Hospital in the management of intestinal intussusception.

PATIENTS AND METHODS

Seventy two patients, aged 2 to 72 months of age, with an uncomplicated intussusception, that were treated by barium or air enema, were studied.

RESULTS

The success rate was 73% with barium reductions, and 100% with air reductions. In 17 patients (24%), enema reduction was unsuccessful and were subjected to a surgical reduction.

CONCLUSIONS

Nonsurgical reduction is safe and effective as the initial treatment of uncomplicated intussusception in children.

Method to correlate 1H MRSI and 18FDG-PET

The in vivo neuronal contribution to human cerebral metabolic rate of glucose (CMRglc), measured by 18FDG-PET, is unknown. Examining the effect of 1H MRSI-derived N-acetyl aspartate (NAA) concentration on positron emission tomography (PET) measures of metabolic activity might indicate the relationship of CMRglc to neuron density. In a population of 19 demented, cognitively impaired, and control subjects, the Miller-Gartner algorithm was applied to whole-brain PET data to isolate the PET signal originating in cortical gray matter alone (GMPET). An analogous procedure applied to multislice proton MRSI data yielded the N-acetyl aspartate concentration in cortical gray matter (GMNAA). In 18 of 19 subjects, a significant linear regression (P < 0.05) resulted when GMPET was plotted against GMNAA, whereby GMPET was higher for higher GMNAA. This suggests that CMRglc rises linearly with increasing neuron density in gray matter. This method may be used to investigate the relationship of CMRglc to neurons in various conditions.

Development of pilus organelle subassemblies in vitro depends on chaperone uncapping of a beta zipper

The major subassemblies of virulence-associated P pili, the pilus rod (comprised of PapA) and tip fibrillum (comprised of PapE), were reconstituted from purified chaperone-subunit complexes in vitro. Subunits are held in assembly-competent conformations in chaperone-subunit complexes prior to their assembly into mature pili. The PapD chaperone binds, in part, to a conserved motif present at the C terminus of the subunits via a beta zippering interaction. Amino acid residues in this conserved motif were also found to be essential for subunit-subunit interactions necessary for the formation of pili, thus revealing a molecular mechanism whereby the PapD chaperone may prevent premature subunit-subunit interactions in the periplasm. Uncapping of the chaperone-protected C terminus of PapA and PapE was mimicked in vitro by freeze-thaw techniques and resulted in the formation of pilus rods and tip fibrillae, respectively. A mutation in the leading edge of the beta zipper of PapA produces pilus rods with an altered helical symmetry and azimuthal disorder. This change in the number of subunits per turn of the helix most likely reflects involvement of the leading edge of the beta zipper in forming a right-handed helical cylinder. Organelle development is a fundamental process in all living cells, and these studies shed new light on how immunoglobulin-like chaperones govern the formation of virulence-associated organelles in pathogenic bacteria.

A role for hepatocyte growth factor/scatter factor in fetal mesenchyme-induced pancreatic beta-cell growth

We have investigated the role of hepatocyte growth factor/scatter factor (HGF/SF) in the growth and/or differentiation of pancreatic islet beta-cells. We found that in the human fetal pancreas immunoreactive HGF/SF receptor (c-met proto-oncogene product) is preferentially associated with the developing beta-cells. In the adult pancreas, c-met messenger RNA is highly enriched in the islets and the immunoreactive protein is also restricted to the islet beta-cells. HGF/SF messenger RNA content of fetal pancreas-derived fibroblasts is more than 10-fold higher than that of adult fibroblasts. Culture of human fetal pancreatic epithelial cells in conditioned medium from the fetal pancreatic fibroblasts caused a 2.4-fold stimulation of the formation of islet-like cell clusters that was due to both mitogenic and morphogenic effects. Beta-cell proliferation in the cell clusters was stimulated 3.5-fold by the conditioned medium, and this was associated with a marked decrease in insulin content. All of the effects of the conditioned medium were blocked by anti-HGF/SF antibody. Specificity was confirmed by overriding the blocking effect of the antibody with excess recombinant HGF/SF. Conditioned medium from adult pancreatic fibroblasts stimulated islet-like cell cluster formation only slightly, and did not affect beta-cell replication. These results suggest that HGF/SF secreted by fetal fibroblasts is mitogenic to beta-cells. Taken together, our findings indicate an important role for HGF/SF in fetal mesenchyme-induced pancreatic beta-cell growth.

Oral human recombinant epidermal growth factor in the treatment of patients with duodenal ulcer

The epidermal growth factor has been shown to be mucoprotective and to accelerate healing of gastroduodenal ulcers in animals. A prospective, positively controlled clinical trial was conducted. Seventy five patients with duodenal ulcer were randomly distributed in three groups to receive oral human recombinant epidermal growth factor in 1% carboxymethyl cellulose at two different doses (450 mg or 600 mg/day), or cimetidine. Treatment was administered up to a maximum of 6 weeks. The most important assessment criteria was the proportion of patients healed after 2, 4 and 6 weeks of treatment determined by endoscopy. Treatment with both doses of epidermal growth factor showed a long-term healing effect in 76.5% at 6 weeks vs 92.5% with cimetidine (p = N.S.). The evolution of the clinical symptoms was similar in the three groups. Adverse reactions were not detected in any of the patients included in this study. To our knowledge, this is the first report on the oral use of epidermal growth factor in humans.

Ontogeny and tissue distribution of human GAD expression

One of the major beta-cell autoantigens associated with IDDM is GAD. Although GAD expression has been detected in adult islets, transcriptional expression of the GAD genes has not been reported during human pancreatic ontogeny. We therefore analyzed patterns of GAD gene transcription by quantitating the mRNAs encoding both the 65- and 67-kDa isoforms (GAD65 and GAD67, respectively) in human fetal, postnatal, and adult pancreases, as well as in isolated adult islets, and examined their tissue-specific expression. Significant levels of pancreatic GAD65 transcripts were already detected at 13 weeks of gestation and were expressed at higher levels in the fetal and infantile pancreas than in the adult pancreas. Isolated adult pancreatic islets were highly enriched in GAD65 mRNA. In contrast, GAD67 transcripts were not detectable in fetal and postnatal pancreases. In addition to the pancreas, marked GAD expression was detected in the brain, whereas other tissues examined contained either low or undetectable GAD transcripts. Triple immunofluorescent staining of fetal and adult pancreases revealed colocalization of GAD65 with alpha- and beta-cells. In the fetal pancreas, strong immunoreactivity for GAD65 was also evident in epithelial cells, which lacked expression of insulin or glucagon, some of which were present in the ductal epithelium, suggesting that GAD65 expression might correlate with endocrine determination. In summary, 1) this is the first demonstration of GAD65 expression in the human fetal pancreas, implicating a potential role during islet development, and 2) GAD65 may be a useful marker for the identification of primitive islet cells.

Kinetics and mechanism of the hydrolysis of depsipeptides catalyzed by the beta-lactamase of Enterobacter cloacae P99

The steady-state kinetics and mechanism of the hydrolysis and aminolysis of a series of acyclic depsipeptides, catalyzed by the class C beta-lactamase of Enterobacter cloacae P99, have been studied in order to more firmly establish the nature of the transition states involved. The class C beta-lactamase of Enterobacter cloacae P99 was employed. The depsipeptide substrates contained a constant acyl group, (phenylacetyl)glycyl, and chemically different leaving groups, m-carboxyphenoxide, m-carboxythiophenoxide, 3-carboxyl-4-nitrophenoxide, lactate, and thiolactate. Evaluation of the steady-state kinetic parameters and the effect of the alternative nucleophile methanol on these parameters and on the product distribution showed that deacylation was largely rate-determining to turnover of the aryl esters under conditions of substrate saturation, while acylation was rate-determining to the alkyl esters. The earlier conclusion [Govardhan & Pratt (1987) Biochemistry 26, 3385-3395] that acylation largely limited the turnover of the aryl esters was shown to be an artifact of phosphate buffer inhibition. The aminolysis of both the aryl the alkyl esters by D-phenylalanine was influenced by binding of the substrate at a second binding site on the acyl-enzyme intermediate. A study of inhibiton of the hydrolysis of (phenylacetyl)-glycyl-D-thiolactate by the aminolysis product (phenylacetyl)glycyl-D-phenylalanine indicated that the second binding site is also available for ligands to bind the free enzyme and to the noncovalent Michaelis complex with this substrate. It is likely that penicillin-recognizing enzymes in general, both beta-lactamases and DD-peptidases, possess an extended substrate-binding site into which a variety of small ligands may bind at any point along the reaction coordinate and, to a greater or lesser extent depending on circumstances, affect catalysis.

Transient radicular irritation followed by meningitis after spinal anesthesia

Neurotoxicity of spinally administered hyperbaric 5% lidocaine is becoming a serious concern in view of the recent literature. We report a case of probable neurotoxicity of hyperbaric 5% lidocaine, followed by an aseptic meningitis. This case report emphasizes the danger of using hyperbaric 5% lidocaine in a too high dose while performing spinal anesthesia.

[Prevalence of protozoa infections in synanthropic rodents in Valdivia City, Chile]

In order to determine the prevalence of infection by blood and intestinal protozoa in 57 synanthropic rodents from Valdivia city, a study was carried out in the period march-september 1986. The group of rodents studied was constituted by 31 Mus musculus, 19 Rattus rattus and 7 Oryzomys longicaudattus, being 42 males and 15 females. Diagnostic forms of protozoa were found in 70.2% of the investigated animals. The presence of five species of enteroprotozoa and one species of hemoflagelate was detected. The number and the corresponding percentages of infected animals were the following: Giardia muris, 21 (36.8%), Hexamita muris, 22 (38.6%), Trichomonas muris, 27 (47.4%), Entamoeba muris 9 (15.8%), Eimeria sp. 15 (26.3%) and Trypanosoma lewisi 9 (15.8%). Not significant differences were observed when considering host or sex of the species found infected. Furthermore, the yielding of fecal examination considering direct examination, sugar solution flotation and SAFS were compared. The sugar solution flotation technique showed the highest percentage diagnosis of coccidia, whereas SAFS was more efficient for detecting G. muris and E. muris.

Relative specificities of a series of beta-lactam-recognizing enzymes towards the side-chains of penicillins and of acyclic thioldepsipeptides

In an attempt to understand more of the subtle differences between bacterial beta-lactamases and DD-peptidases, comparisons have been made between the specificities of these enzymes towards the phenylacetyl side chain, generally thought to be favoured by beta-lactamases, and the NN'-diacetyl-L-lysyl side chain, widely employed in low-molecular-mass substrates of DD-peptidases. These comparisons were carried out with both a penicillin and an acyclic thioldepsipeptide reaction nucleus and employing a range of both beta-lactamases and DD-peptidases. Rather contrary to general expectations, a general preference for reaction of both groups of enzymes with penicillins rather than thioldepsipeptides was observed and for the phenylacetyl rather than the NN'-diacetyl-L-lysyl side chain. Quantitative comparisons suggested that the side chains of penicillins may be bound in relatively similar sites in all of the enzymes whereas the side chains of thioldepsipeptides are more heterogeneously bound, both with respect to each other and to the comparable side chains of penicillins.

Complete vesiculation of Golgi membranes and inhibition of protein transport by a novel sea sponge metabolite, ilimaquinone

We have identified a novel natural metabolite, ilimaquinone (IQ), from sea sponges that causes Golgi membranes to break down completely in vivo into small vesicular structures (called vesiculated Golgi membranes [VGMs]). Under these conditions, transport of newly synthesized proteins from endoplasmic reticulum (ER) to the cis-Golgi-derived VGMs is unaffected; however, further transport along the secretory pathway is blocked. Upon removal of the drug, VGMs reassemble rapidly into a Golgi complex, and protein transport is restored. By employing a cell-free system that reconstitutes vesicular transport between successive Golgi cisternae, we provide evidence that the inhibition of protein transport by IQ is specifically due to an inhibition of transport vesicle formation. In addition, like brefeldin A (BFA), IQ treatment prevents the association of beta-COP and ADP-ribosylation factor to the Golgi membranes; however, unlike BFA treatment, there is no retrograde transport of Golgi enzymes into ER.

[HIV infection. Diagnosis in the national network of laboratories in Chile]

A national network including 114 blood banks and laboratories performs screening for HIV infection on approximately 250,000 blood donors a year. This represents 100% coverage of blood transfusions performed in Chile. Up to December 1990. 4956 samples had been sent to the National Reference Center for AIDS for supplementary studies. HIV infection was confirmed in 1465 (29.6%). A prior study covering the first semester of 1989 showed a 26.9% confirmation rate for HIV infection on 845 serum samples. Technical errors including sample contamination, poor cleaning, decreasing titers of controls and erratic criteria regarding the need for supplementary studies may explain the low confirmation rate reported in this study.

[Myocardial damage following neonatal severe asphyxia]

Sixteen newborn infants with severe asphyxia were prospectively studied for evidence of secondary myocardial damage and, in that case, their clinical findings. Myocardial damage was diagnosed in three term newborn infants of adequate weight for gestational age (18.7%) by means of serial electrocardiograms taken in the first 72 hours of life. Two of them showed evidence of diffuse subendocardial ischemia and a third one showed electrocardiographic signs suggesting necrosis of the left ventricular posteroinferior wall. Neither creatine-phosphokinase serum activity nor its muscle brain MB isoenzyme were useful in the identification of myocardial damage. All three affected neonates developed respiratory distress syndrome without signs of cardiac failure and one of them died. The histopathological study of this late one showed localized hemorrhage of the papillary muscles and interventricular septum. These finding underscore the need for serial electrocardiographic recordings in newborns with severe asphyxia, since cardiac dysfunction may inadvertently occur under the appearance of respiratory distress syndrome.

[Patients with an indeterminate serological diagnosis of HIV-1 infection]

Western blot is the technique most frequently used to determine the presence of HIV-1 antibodies. However, some patients remain with an indeterminate diagnosis for HIV-1 according to the technique. We followed 8 such patients for 2 to 18 months. Immunologic studies included standard ELISA, immunofluorescence and Abbott anti-p24 ELISA. We found selective reactivity for certain viral proteins such as isolated p24, p24 plus p51 or p55, gp41 plus gp 120, p17 plus p24 and p25.

[Primary cutaneous lymphoma: experience with 10 cases]

We report 10 patients with cutaneous lymphoma along with their clinical findings, staging, histopathologic characteristics by light microscopy, and results of anti-HTLV antibody screening. The immunotype was T cell in all. Three patients were diagnosed as having Lymphomatoid papulosis: one of them evolved to Mycosis fungoides, another showed progression to Immunoblastic lymphoma and a third remains as such. Two patients had a long standing Mycosis fungoides and, finally, 5 cases had peripheral T-cell lymphoma. Of the latter, 2 progressed rapidly to death.

Regional cerebral blood flow velocity patterns in newborn infants

Using range-gated pulsed Doppler sonography, cerebral blood flow velocity (CBFV) waveforms from the anterior cerebral artery (ACA), middle cerebral artery (MCA) and circle of Willis artery (CW) were examined in a total of 34 newborn infants. We compared the pulsatility index (PI) from the three cerebral arteries sampled in 10 term and 10 preterm (29 +/- 2 weeks) newborn infants without a history of perinatal asphyxia or intracranial pathology. The Pl in the ACA ranged from 0.60 to 1.03. There were no significant differences in Pl between the three vessels by paired comparisons. The Pl of the MCA differed from that of the ACA by 0.00 +/- 0.05. The variation coefficient (CV) was 7%. For CW with ACA, the difference was 0.00 +/- 0.04 and CV was 6%. Both intra- and interexaminer variation in Pl measurements were studied in another 14 infants. The variation coefficients were 5-8% for all three cerebral arteries. We showed that CBFV waveform patterns were similar in regional cerebral arteries, with Pl being a consistent CBFV index. In normal cerebral circulation, the intervessel Pl differences were within observer variations. Deviation from this may suggest abnormal regional cerebral haemodynamics.

Focal adrenal hemorrhage: a new US appearance

The ultrasonographic (US) appearance of neonatal adrenal hemorrhage has been described as a mass obliterating the normal contour of the entire gland. In the four cases described, different US appearances were found: In three, the hemorrhage was focal with the uninvolved portion of the gland visualized adjacent to the hemorrhage; in the fourth patient, hemorrhage involved primarily the medulla. Excellent computed tomographic or pathologic correlation with the US appearance was demonstrated. These findings suggest that adrenal hemorrhage should be considered in the differential diagnosis of focal adrenal masses in the neonate.