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Biomedical subjects

E Jacobs

Publications and source records attributed to E Jacobs.

At least 91 records · Page 5Linked to original sources
PubMed1993

Recurrent attacks of unconsciousness with diffuse EEG alpha activity.

A 45-year-old patient presented with recurrent attacks of unconsciousness, which resembled sleep. However, EEG recordings during these attacks showed diffuse, frontal-dominant 10-Hz alpha activity. Both the attacks and EEG changes reversed promptly with intravenous flumazenil, but not with methylphenidate, atropine or placebo. The attacks could not be prevented with methysergide, flumazenil, clonidine, piracetam or phenytoin. Laboratory investigations revealed a temporal lobe arachnoid cyst, a distal motor and sensory polyneuropathy, abnormal auditory evoked responses during the attack, an abnormal silent period latency and abnormal melatonin regulation. Similar attacks were reported by history in two siblings and in the proband's late father. It is postulated that the attacks of unconsciousness could involve gamma-aminobutyric acid- (GABA)-mediated mechanisms.

Alpha Rhythm↗
PubMed1993

Reversible inhibition of urea exchange in rat hepatocytes.

Urea exchange is enhanced in renal collecting duct cells and erythrocytes by transporters which can be inhibited by phloretin and urea analogs such as thiourea. In this study, evidence for a comparable transporter was found in rat livers perfused with solutions which contained no red cells and in suspensions of hepatocytes. Bolus injections containing 125I-albumin (intravascular indicator), 99mTc-DTPA (extracellular indicator), 3HOH (water indicator), and [14C]urea were administered into the portal vein and fluid was collected from the hepatic vein. Under control conditions, [14C]urea and 3HOH emerged from the hepatic vein at nearly the same rate. However when the perfusate contained 2.5 mM phloretin (equivalent to 0.058 mM phloretin not bound to albumin), the amount of [14C]urea which had been recovered in the hepatic venous outflow by the time of peak 125I-albumin concentrations exceeded 3HOH recovery by a factor of 2.31 +/- 0.23 (n = 7). When the perfusate contained 200 mM thiourea, the comparable recovery of [14C]urea from the hepatic veins exceeded that of 3HOH by a factor of 3.48 +/- 0.44 (n = 7). These effects were at least partially reversible and suggested inhibition of urea transporters in hepatocytes. This conclusion was supported by studies of unloading of [14C]urea from hepatocytes which were exposed to unlabeled solutions: in the presence of phloretin, the amount of [14C]urea remaining within hepatocytes at 4 s was approximately twice that remaining in hepatocytes which had not been exposed to phloretin. Rapid transport of urea out of hepatocytes may increase urea synthesis and minimize cellular swelling due to urea accumulation.

Animals↗
PubMed1993

Comparison of bedside coagulation monitoring tests with standard laboratory tests in patients after cardiac surgery.

We compared portable bedside tests of whole blood coagulation with standard laboratory plasma coagulation tests to assess the accuracy and precision of the bedside tests in a clinical setting (postcardiac surgery). The Ciba Corning 512 Coagulation Monitor (Ciba Corning Diagnostics Corp., Medfield, MA) and the Hemochron 801 (International Technidyne Corp., Edison, NJ) were tested. One hundred forty-one patients who underwent cardiac surgery requiring cardiopulmonary bypass were evaluated upon arrival in the intensive care unit. Nine milliliters of fresh whole blood were used to obtain the prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), and the heparin-neutralized thrombin time (HNTT) that were measured by bedside coagulation monitors. TT and HNTT were only measured by the Hemochron method. Blood from the same sample was also sent to the Hospital Stat Laboratory for simultaneous comparison of bedside results and standard coagulation tests. For PT and aPTT testing, an accuracy of +/- 10% and a precision of +/- 25% were considered clinically acceptable. Both of the PT tests met the dual criteria for clinical acceptability, but the aPTT tests did not meet either criterion. The difference between Hemochron TT and Hemochron HNTT correlated weakly, but significantly, with laboratory aPTT ratio (r = 0.52, P < 0.001). The slope of the regression line indicated that a TT-HNTT difference > 30 s correlated with an aPTT > 1.5 x control. We conclude that, in the postoperative cardiac surgical patient, PT was both accurate and precise in two commercially available tests, but aPTT was not.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation↗
PubMed1993

More than loose change: household health spending in the United States and Canada.

A key point of comparison between U.S. and Canadian health spending is what amount citizens spend for health coverage, given their respective health systems. A comparison of household spending surveys in the two countries shows that Canadian households pay about half of what American households pay for health coverage, but their personal tax burden is almost twice that of Americans. Net personal consumption thus is quite similar between the two countries. Total household health spending in the United States amounted to $215.6 billion in 1989--one-third of the total spent on health that year.

Adult↗
PubMed1993

Mycoplasma pneumoniae infections in schoolchildren of a tropical community.

Information about Mycoplasma pneumoniae infections in tropical countries is scarce. This study reports the prevalence of anti-M. pneumoniae antibodies among schoolchildren from the tropical community of Palmares, Costa Rica. The serum samples were collected in July 1983 from 2021 children who represented 99% of the county's schoolchildren. Immunofluorescence (IFA) and in some cases ELISA serological methods were applied. IFA seropositivity was high (53%) and ranged from 22% to 79% depending on the district. Marked differences in the prevalence of antibodies in children attending schools of neighboring communities, suggest that the school may be epidemiologically important as a focus to spread mycoplasma infections among children. The presence of a low percentage of antibodies (IgG, IgM and IgA) against the 168 kd- M. pneumoniae antigen suggested that there were few cases of active or recent infections.

Child↗
PubMed1993

HemoCue beta-glucose photometer evaluated for use in a neonatal intensive care unit.

We evaluated the HemoCue beta-Glucose Photometer system for use in our neonatal intensive care unit by assaying 178 heparinized whole-blood samples obtained by heel stick. The required sample size is 5 microL. Plasma glucose was analysed by a glucose oxidase/oxygen electrode methodology. Across the glucose range of 1.28-21.87 mmol/L, the regression slope was 0.976 (r = 0.976, Sy/x = 0.475). For samples with hematocrit < or = 0.30, the regression slope was 0.981 (r = 0.950, Sy/x = 0.415); for hematocrit of 0.31-0.49, the regression slope was 0.984 (r = 0.972, Sy/x = 0.508); and for hematocrit > or = 0.50, the regression slope was 0.959 (r = 0.988, Sy/x = 0.394). Human whole blood, bovine whole blood, and bovine serum-based quality-control materials were studied. Except for assays of the low-concentration human control material, the total CV was < 3.5%. The accuracy and precision of the HemoCue system were comparable with those of conventional laboratory instrumentation.

Biosensing Techniques↗
PubMed1993

Performance of Gem Premier blood gas/electrolyte analyzer evaluated.

We evaluated a new analyzer designed for point-of-care testing of blood gases, sodium, potassium, ionized calcium, and hematocrit. The Gem Premier (Mallinckrodt) system has two components: the analyzer and a disposable cartridge. Analysis takes place in the cartridge, which contains the electrochemical sensors, the calibrants, the reagents, the sampling stylus, and the waste container. The system was evaluated for imprecision and accuracy. With aqueous control materials, total imprecision (CV) was: pH, 0.10-0.18%; PCO2, 3.16-5.78%; PO2, 2.92-4.85%; sodium, 0.82-1.44%; potassium, 1.35-1.48%; ionized calcium, 0.75-1.45%; and hematocrit, 1.13-1.83%. Accuracy of the system was assessed by split-sample comparison with the Radiometer ABL 330 blood gas analyzer for pH and blood gases, the Nova Stat Profile 5 for whole-blood electrolyte and hematocrit analysis, and the IL Phoenix for plasma electrolyte analysis. After outlier correction, regression statistics were excellent for all analytes except sodium, which demonstrated Sy[x values between 1.80 and 2.30 mmol/L and 0.85 < or = r < 0.90.

Blood Gas Analysis↗
PubMed1993

Analytical evaluation of i-STAT Portable Clinical Analyzer and use by nonlaboratory health-care professionals.

We evaluated the performance of the i-STAT Portable Clinical Analyzer, a hand-held instrument that, with its current cartridge, analyzes for electrolytes, urea nitrogen, glucose, and hematocrit in approximately 60 microL of whole blood in approximately 90 s. Accuracy, imprecision, and linearity studies were performed with aqueous controls and standards and by split-sample analysis. Intrarun imprecision (CV) ranged from 0.34% to 3.97%. Total imprecision over a 2-month period ranged from 0.42% to 4.83%, with urea nitrogen and glucose analyses generating the higher values. Patients' results from the Portable Clinical Analyzer correlated well with those obtained for whole blood or plasma by the Nova Stat Profile 5, the Beckman Synchron CX3, or the Technicon H1 Hematology Analyzer, with Sylx values < 0.2 mmol/L for potassium; < 1.5 mmol/L for sodium, glucose, and urea nitrogen; < 2.4 mmol/L for chloride, and < 2.4% for hematocrit. We also ascertained imprecision and accuracy of the system placed in a cardiothoracic intensive-care unit and operated by nurses. There were no significant differences in either the imprecision or accuracy of the system in this setting. We conclude that operator technique is not a factor in the analytical performance of the system and that it can be used by nonlaboratorians with a high degree of confidence that reliable results will be obtained.

Autoanalysis↗
PubMed1992

An idiotypic replica of carcinoembryonic antigen inducing cellular and humoral responses directed against human colorectal tumours.

A monoclonal anti-idiotypic antibody (anti-Id MAb) 708 (IgG2b), which inhibited the binding of NCRC23 (IgG1) MAb to CEA and prevented radiolabelled CEA from binding to MAb NCRC23, was produced. No recognition of 3 other anti-CEA antibodies, 3 other IgG1 or 2 IgM MAbs was observed with this anti-idiotypic antibody. When an immunoblotting technique was used, 708 anti-Id MAb failed to bind to isolated heavy or light chains of MAb NCRC23, whereas binding was observed with intact antibody. Mouse, rat and human lymphocytes (in vitro) were immunized with 708 anti-Id MAb and the resultant Ab3 antibodies all inhibited binding of labelled 708 anti-Id MAb to MAb NCRC23 and also reacted with CEA, showing that 708 anti-Id MAb induced anti-CEA antibody responses. Similarly, mice immunized with 708 anti-Id MAb could be restimulated in vitro with either CEA or tumour cells expressing CEA which induced specific T-cell proliferative responses. Human tumour-infiltrating lymphocytes isolated from colorectal tumours or peripheral blood T cells from cancer patients were stimulated in vitro with 708 anti-Id MAb or an irrelevant IgG2b antibody. Six days later both sets of lymphocytes were restimulated with CEA, and lymphocytes primed to 708 anti-Id MAb proliferated in response to CEA. These results suggest that 708 anti-Id MAb can act as an idiotypic replica of CEA and stimulate cellular and humoral anti-CEA immune responses. It is therefore of great interest as an idiotypic vaccine against colorectal cancer.

Animals↗
PubMed1992

Elevated risk of Helicobacter pylori infection in submarine crews.

In a prospective study designed to elucidate the route of transmission of Helicobacter pylori, the seroprevalence and incidence of Helicobacter pylori infection was determined in the following branches of the armed forces presumed to be at increased risk of acquiring transmissible diseases by the fecal-oral or oral-oral route: German submarine crews (n = 64, mean age 26.2 years) and regular officers of the French infantry (n = 51, mean age 26.5 years) who had served for a minimum of three years. The submarine crews were compared with air force staff (n = 74, mean age 23.7 years), and the French officers with French infantry recruits (n = 135, mean age 20.5 years) who started their service at the beginning of the study. The frequency of IgG and IgA antibody responses to the 120, 88, 86 and 82 kDa proteins was determined by the immunoblot method. The frequency of a positive antibody response was strongly dependent on age (p less than 0.001). When results were controlled for age by the logistic regression analysis, the submarine crews revealed significantly increased frequencies of the IgG and IgA responses compared to air force staff. The antibody responses of French officers and recruits were not significantly different. It is concluded that submarine crews serving during their missions in an overcrowded space with extremely limited sanitary facilities must be considered a high-risk group for Helicobacter pylori infection. These results strongly suggest person-to-person transmission of Helicobacter pylori, by either the oral-oral or the fecal-oral route.

Adult↗
PubMed1992

Simultaneous use of two retroviral vectors in human gene marking trials: feasibility and potential applications.

Two Moloney murine leukemia virus (Mo-MLV)-based neoR retroviral vectors--LNL6 and G1Na--were used to transduce various human tumor-infiltrating lymphocytes (TIL) populations. These groups included bulk CD(8+)- and CD(4+)-enriched TIL from human renal cell carcinomas and melanomas. Transduction efficiencies averaged 5% for single 4-hr supernatant infections. Integrated provirus could be detected for up to 4 weeks of in vitro culture. LNL6 provirus could be distinguished from G1Na provirus using specific polymerase chain reaction (PCR) primers. A single neomycin phosphotransferase (neoR) gene copy could be detected in 10(5) TIL. Using quantitative PCR, the relative ratio of LNL6 to G1Na copies in the same sample could be determined even at low copy numbers. These preclinical studies demonstrate the feasibility of using two retroviral marking vectors in human gene therapy efforts.

Base Sequence↗
PubMed1992

Adherence epitopes of Mycoplasma genitalium adhesin.

The adherence-mediating sites of the 153 kDa adhesin of Mycoplasma genitalium (MgPa-protein) were characterized at the amino acid sequence level using six monoclonal anti-MgPa antibodies which showed adherence-inhibiting activity. For characterization of the regions to which antibody bound, three segments of the adhesin (N-terminal region, a D1-domain located approximately in the middle of the molecule and a D2-domain located near to the C-terminus) were synthesized as overlapping octapeptides. These regions were chosen in analogy to the three domains of Mycoplasma pneumoniae that are involved in the adhesion process. Whereas two monoclonal antibodies (mAb 5B11 and mAb 6F3) bound exclusively to an epitope in the N-region, mAb 3B7 and mAb 6A2 reacted with two distinct epitopes of the D2-domain only. Binding to short synthetic peptides of different regions was analysed for mAb 3A12 (N-region and D1-region) and mAb 2B6 (N-region and D2-region). Close proximity of the N-region and the D2-region in the native MgPa-protein of M. genitalium was indicated in a competitive ELISA test, using freshly harvested M. genitalium cells. Epitope mapping and competition experiments with monoclonal anti-MgPa antibodies revealed interesting differences in the adherence-mediating sites of MgPa and the adhesin (P1-protein) of M. pneumoniae. Whereas a three-dimensional arrangement of protein loops is suggested for both native adhesins, the MgPa-protein and the P1-protein adherence-mediating epitopes are located in non-homologous regions of these two related proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesins, Bacterial↗
PubMed1992

[Diagnosis of chlamydia and mycoplasma infections of the respiratory tract].

Chlamydia- and mycoplasma diseases are nowadays still confirmed by serology. Since during the acute phase the serological results are often negative, the conformation of an atypical pneumonia due to M. pneumoniae or chlamydia species must be based on more rapid tests, i.e. direct antigen or hybridisation approaches.

Chlamydia Infections↗
PubMed1991

Simultaneous expression of the S and L surface antigens of hepatitis B, and formation of mixed particles in the methylotrophic yeast, Hansenula polymorpha.

An expression system has been developed for the methylotrophic yeast Hansenula polymorpha and used to co-express both the L (preS1-S2-S) and S hepatitis B surface antigens (HBsAg) under the control of strong methanol-inducible promoters derived from the methanol oxidase and from the formate dehydrogenase genes. A unique feature of this H. polymorpha expression system is the possibility of integrating up to 100 copies of an expression cassette via a multimeric integration mechanism. Several multimeric integrants containing various numbers of L and S expression cassettes were constructed to give a spectrum of strains characterized by different L to S ratios. The expression level of S antigen was 5-8% of the total soluble cell protein. Analysis by sucrose and CsCl density gradient centrifugation and by particle-specific immunoassays demonstrated that the synthesized HBsAg spontaneously assembled into composite subviral particles containing both S and L proteins. Only a minor portion of the L protein was found to be glycosylated. These H polymorpha-derived composite particles can be used for the production of a hepatitis B virus vaccine with the potential for improved immunogenicity due to the presence of a wider spectrum of epitopes and negligible glycosylation.

Base Sequence↗
PubMed1991

Cyst of the gallbladder.

A cyst of the gallbladder is a very rare lesion. The possible causes of such an anomaly are reviewed. It may be acquired or congenital. The latter is particularly exceptional. A case of congenital cyst is reported and illustrated by various imaging techniques.

Cysts↗
PubMed1991

Comparison of host responses after intranasal infection of guinea-pigs with Mycoplasma genitalium or with Mycoplasma pneumoniae.

Guinea-pigs were infected intranasally with Mycoplasma genitalium or Mycoplasma pneumoniae. The lung lesions produced by the two mycoplasmas were comparable in extent and histological pattern. Sera of both animal groups taken 2 weeks after infection reacted strongly in the complement fixation test with the M. pneumoniae glycolipid extract. In an ELISA using the respective adherence proteins (P1-protein of M. pneumoniae and MgPa of M. genitalium), strong specific activity, but also considerable cross-reactions were found. Epitope analysis by using overlapping octapeptides of a P1-region immunologically active in human M. pneumoniae infections and of the corresponding MgPa-region revealed six common epitopes but also one M. genitalium and two M. pneumoniae specific determinants. For analysis of a possible pathogenicity of M. genitalium in the human respiratory tract species-specific tests have to be developed.

Administration, Intranasal↗
PubMed1991

The mature MgPa-adhesin of Mycoplasma genitalium.

A high molecular weight protein of Mycoplasma genitalium (MgPa-protein) was isolated by fractionated solubilization with 1% CHAPS, followed by subsequent extraction with 2% octylglucoside and size exclusion chromatography. The comparison of the N-terminal sequence reported here with published nucleotide sequence data revealed the existence of a signal sequence; the molecular weight of the mature MgPa-protein was calculated to be 153, 134 dalton. The protein shares antigenic determinants with the adhesin of Mycoplasma pneumoniae (P1-protein). Therefore the amino acid sequence of the MgPa-protein was matched to the P1-protein sequence. Five of seven computer predicted hydrophobic regions of both amino acid sequences were located in corresponding regions.

Adhesins, Bacterial↗