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E Jacob

Publications and source records attributed to E Jacob.

At least 55 records · Page 3Linked to original sources
PubMed1990

Isolation of L-3-phenyllactyl-Leu-Arg-Asn-NH2 (Antho-RNamide), a sea anemone neuropeptide containing an unusual amino-terminal blocking group.

Using a radioimmunoassay for the carboxyl-terminal sequence Arg-Asn-NH2, we have purified a peptide from acetic acid extracts of the sea anemone Anthopleura elegantissima. By classical amino acid analyses, mass spectrometry, and 1H NMR spectroscopy, the structure of this peptide was determined as 3-phenyllactyl-Leu-Arg-Asn-NH2. By using reversed-phase HPLC and a chiral mobile phase, it was shown that the 3-phenyllactyl group had the L configuration. Immunocytochemical staining with antiserum against Arg-Asn-NH2 showed that L-3-phenyllactyl-Leu-Arg-Asn-NH2 (Antho-RNamide) was localized in neurons of sea anemones. The L-3-phenyllactyl group has not been found earlier in neuropeptides of vertebrates or higher invertebrates. We propose that this residue renders Antho-RNamide resistant to nonspecific aminopeptidases, thereby increasing the stability of the peptide after neuronal release.

Amino Acid Sequence↗
PubMed1990

Use of computers in quality assurance of laboratory testing.

Implementation of comprehensive internal quality control programmes and participation in external quality assessment schemes to monitor analytical performance of laboratory tests have been widely accepted as an essential and integral part of good laboratory practice. As these programmes involve a great deal of repetitive statistical calculations and graphic presentation of data on quality control materials, many laboratories and practically all organisers of inter-laboratory quality assessment schemes increasingly rely on computers to handle the burdensome processing of data and to provide timely feedback in a manner that is easily understood and readily interpreted by analytical staff. However, in spite of the best effort to ensure reliable analytical performance, spurious and misleading results can still occur as a result of non-analytical errors which are not readily detected by methods designed to monitor the quality of analytical process. The use of sophisticated computer system has enabled our laboratory to check for the existence of some of these errors. This paper describes the application of computers in a variety of internal and external quality assessment programmes and demonstrates the usefulness of retrieving patients' cumulative test results and at the same time performing delta or percentage difference checks on such data in the detection of non-analytical errors and unexpected variations in results. The role of the computer in minimising transcription errors, reducing turn-around time of testing and reporting, as well as improving the quality of laboratory reports is also mentioned.

Clinical Laboratory Information Systems↗
PubMed1989

Synthesis and secretion of plasminogen activators and plasminogen activator inhibitors in cell lines of different groups of human lung tumors.

Several human lung tumor cell lines derived from large cell, squamous cell, and small cell carcinomas, as well as from mesotheliomas of the lung have been investigated for their gene expression and secretion of urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitors 1 and 2. All bronchogenic non-small cell carcinoma-derived cell lines studied could produce either plasminogen activators, their inhibitors, or both components, whereas in small cell lung carcinoma cell lines and cell lines derived from mesothelioma of the lung, no substantial amounts of any of these substances were synthesized. In detail, a large cell carcinoma-derived cell line, LCLC 97TM1, constitutively secreted large amounts of plasminogen activator. Northern blot analysis revealed RNA specific for u-PA and t-PA. Another large cell carcinoma-derived cell line, LCLC 103H, secreted smaller amounts of plasminogen activator and, additionally, plasminogen activator inhibitor. Specific mRNAs for u-PA and plasminogen activator inhibitors 1 and 2 were found in this cell line. In contrast, squamous cell carcinoma-derived cell lines secreted plasminogen activator only after treatment with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate; enhanced levels of u-PA, t-PA, and plasminogen activator inhibitor 1 mRNAs could then be demonstrated. The different expression of the plasminogen activator enzyme system distinguishes cell lines derived of non-small cell lung carcinoma from those of small cell lung carcinoma and may also reflect significant differences in the biological behavior of these tumor types.

Autoradiography↗
PubMed1989

Hyperpolarization and short-circuiting as mechanisms of seizure prevention following febrile convulsions.

Though children with febrile convulsions only have seizures in the early stage of a febrile illness and not later, these seizures have been attributed to the fever. We studied the serum electrolyte and metabolite profiles in the later stage to see if there were fuel responses resulting in electrophysiological changes which prevented further seizure activity. On admission there was intracellular glucose starvation, as evidenced by increased ketones and lactate, and the possibility of the failure of some electrolyte pumps, as suggested by hyperuricaemia (energy crisis) and decreased serum Na+, Cl- and Ca2+. However, there was adaptive hyperglycemia and decreased serum K+. It seems likely that the hyperglycemia, induced the uptake of K+ by neurones, enabling their repolarization and hyperpolarization, which prevented further seizure activity, while Cl- influx short-circuited depolarizing currents produced by Na+ influx. Studies during recovery showed a gradual return of the metabolic and electrolyte aberrations to normality, suggesting that the provision of energy through adaptation to the stress, enabled recovery of the aforementioned pumps.

Blood Glucose↗
PubMed1989

Infection in war wounds: experience in recent military conflicts and future considerations.

War wounds are characterized by devitalized tissue, the presence of debris, and contamination by bacteria--factors that contribute to the establishment of wound infection. A review of the literature regarding the incidence of wound infection in recent military conflicts strongly suggests that infection in open war wounds occurs with relative frequency despite strict adherence to the principles of surgical debridement and administration of "prophylactic" antibiotics. Further research leading to improved methods of preventing wound sepsis is warranted in order to reduce the incidence of wound infections in the future.

Acute Disease↗
PubMed1989

Clinical biochemistry in Singapore.

During the period from 1982 to mid-1989, there has been very significant changes and improvement in the practice and application of clinical biochemistry in Singapore. This paper highlights recent developments in the repertoire of biochemical analyses, utilisation of laboratory tests, biochemical screening in preventive health care, handling and delivery of patient specimens, advances in analytical techniques, automation, computerisation, quality assurance, training of laboratory personnel, and professional activities. It also draws attention to the restructuring of the Singapore General Hospital and the government Department of Pathology which frees these government institutions from the constraints of the civil service so that they would be sufficiently flexible to respond readily to the changing needs and expectations of the patients and users of laboratory services. This is the most prominent event and policy change in the history of health care services in Singapore that is expected to result in more cost-effective utilisation of resources and greater improvement in the quality of health care.

Automation↗
PubMed1987

The effect of dapsone-pyrimethamine on immunoglobulin concentrations in malaria chemoprophylaxis.

Immunoglobulins IgG, IgM, IgA were estimated on 3 occasions in 59 male volunteers who were taking dapsone-pyrimethamine once weekly (dapsone: 100 mg + pyrimethamine: 12.5 mg) for malaria chemoprophylaxis. Immunoglobulins IgG and IgM measured at the 7th week of chemoprophylaxis were significantly lower than baseline values (using Students' t-test for paired data), but none of the values were below 700 mg% for IgG or 30 mg% for IgM. Immunoglobulin concentrations estimated in 45 of the 59 men 6 weeks after discontinuation of chemoprophylaxis showed a return to baseline for IgM but not IgG, which remained low. On all 3 occasions there was no significant change in the IgA concentrations. The clinical implication of these findings is not known. Further studies are required to define the effects of antimalarial drugs on the antibody response to infection and immunization.

Adolescent↗
PubMed1987

'M' cells in the follicle-associated epithelium of the human colon.

The morphology of the epithelium overlying human colonic mucosal lymphoid follicles has been studied by electron microscopy. Epithelial crypts stop at the edge of the follicle and the centre is covered by a single layer of enterocytes. Numerous lymphocytes and, occasionally, other mononuclear cells, are associated with these enterocytes. The lymphocytes are situated in the intercellular spaces, invaginate the lateral cell wall and ultimately appear to be completely surrounded by the enterocyte. When the lymphocyte is near the centre of the enterocyte there is usually little change in enterocyte morphology, but when the lymphocyte is near the apical surface of the enterocyte, the latter closely resembles the membranous epithelial cells ('M' cells) of human small intestine. It is probable that, as with the 'M' cells in the small intestine, these colonic 'M' cells have an antigen sampling function. Their presence may explain the localization of the early lesions of some colonic inflammatory diseases, including Crohn's disease. They may also provide a portal of entry for some rectally-transmitted viral infections.

Colon↗
PubMed1987

Antibody response to teichoic acid and peptidoglycan in Staphylococcus aureus osteomyelitis.

An enzyme-linked immunosorbent assay was used to evaluate the immunoglobulin G (IgG) response to Staphylococcus aureus crude teichoic acid (TA) and peptidoglycan (PG) in both rabbits and patients with osteomyelitis. In rabbits with experimental S. aureus osteomyelitis, elevated levels of IgG to TA were present in 13/18 (72%) of the serum samples obtained at 4 and 10 weeks postinfection. In contrast, only 5/18 (28%) of these sera were found to be positive for antibodies to PG. Of a total of 39 patients with confirmed S. aureus osteomyelitis (11 acute, 28 chronic), IgG to TA was elevated in 17 (44%), whereas antibodies to PG were found to be increased in only 1 (3%). Cross-reacting antibodies to S. aureus TA were detected in only 1/18 (6%) of the patients with osteomyelitis caused by organisms other than S. aureus. These studies indicate that IgG to TA is more prevalent than IgG to PG in patients with staphylococcal osteomyelitis. Although these results are encouraging, a larger number of patients is required for an adequate evaluation of the TA enzyme-linked immunosorbent assay for the diagnosis and management of suspected S. aureus osteomyelitis.

Acute Disease↗
PubMed1987

Increase in bile secretion after water ingestion in cholecystectomised patients.

The effect of water ingestion on bile secretion was investigated in nine cholecystectomised patients with T-tube biliary drainage. The effect of ingestion of a standard meal on bile secretion was also studied in these patients. Water ingestion produced a significant increase in bile secretion compared with fasting levels. This increase in bile secretion was comparable to that produced by a standard meal. Ingestion of water or meal did not produce any significant change in bile osmolality or sodium and potassium concentrations of bile.

Aged↗
PubMed1986

Lactate production in type B hyperlactataemia due to infective encephalopathy.

We have suggested that the neuroglycopenia of infective encephalopathy results in increased lactate production in muscle as an alternative cerebral fuel. Two probable mechanisms for enhanced lactate production in infective encephalopathy are fatty acidaemia and increased LDH activity. Hyperglycaemia-producing infusions should then result in clinical and metabolic recovery. Twenty-two children with encepahlopathy were studied over 2 1/2 week periods. There was normoglycaemia at admission together with hyperlactataemia (p less than 0.004), fatty acidaemia (p less than 0.004) and increased serum LDH activity (p less than 0.005). Therapeutic hyperglycaemia resulted in recovery and a progressive return of metabolic aberrations to normality. Two case reports detail the responses to such management.

Blood Glucose↗
PubMed1986

Computers in clinical laboratory management in Singapore.

In 1974, an off-line mini-computer system was introduced in the Clinical Biochemistry Laboratories of the Government Department of Pathology in Singapore. With the resiting of the 24-hour emergency biochemistry laboratory on the same floor as the Haematology Department within the new Singapore General Hospital, an on-line computer system was installed in 1983 to serve both the emergency biochemistry and haematology laboratories. An almost identical on-line system was also purchased in 1984 to replace the aged off-line system at the Department of Pathology. A description of the new computer systems based on Eclipse S/140 computers and Medical Information Technology (Meditech) software using Meditech Interpretive Information System (MIIS) language will be given. The specific features required and the selection criteria for the on-line systems are also discussed. The systems are used for the acquisition and processing of all patient and test data of the laboratories, direct capture of data from automated instruments, generation of work schedules and laboratory reports, compilation of work done, workload and revenue statistics and a variety of other reports. Patient cumulative records and quality control statistics are available on a real-time basis, thus greatly facilitating enquiries on patient results and monitoring of analytical performance. Prior experience with an off-line system and careful planning have been helpful in greatly shortening the preparatory period required for the smooth implementation of the on-line systems. Use of the systems has significantly improved laboratory management and has resulted in improved quality, and higher efficiency and productivity.

Chemistry, Clinical↗
PubMed1985

A comparison of freeze-dried allogeneic and fresh autologous vascularized rib grafts in dog radial discontinuity defects.

The limitations of autologous vascularized grafts include morbidity at the donor site and the increased surgical time associated with graft retrieval. To overcome these limitations, freeze-dried allogeneic and fresh autologous vascularized rib grafts were compared in 6-cm mid-radial defects of dogs. There was no statistically significant difference between the two graft systems when postoperative radiographs, in vivo intraarterial angiograms, and histologic evaluation of vessel patency were compared. However, clinical assessment of graft stability favored the autologous grafts, and force deflection tests revealed that the freeze-dried grafts had only 64% of the graft strength of the fresh autologous grafts at the end of the experiment at 26 weeks.

Angiography↗
PubMed1985

Enzyme-linked immunosorbent assay for detection of antibodies to Staphylococcus aureus cell walls in experimental osteomyelitis.

An enzyme-linked immunosorbent assay was used to evaluate and compare the immunoglobulin G antibody response to Staphylococcus aureus cell walls of rabbits with either chronic staphylococcal osteomyelitis or subcutaneous abscesses. Osteomyelitis of the femur was produced by the intramedullary application of a sclerosing agent (3% sodium tetradecyl sulfate) and S. aureus. Radiographic evidence of osteomyelitis was observed in 10 of the 13 animals that survived the 10-week experimental period, and the diagnosis was confirmed by histopathology in 8 of the 10 instances. Abscess formation was initiated in a separate group of rabbits by the subcutaneous injection of S. aureus cells. All 10 of these rabbits subsequently developed abscesses, which usually resolved spontaneously within 3 to 5 weeks. Elevated levels of immunoglobulin G antibodies to the cell wall antigen were detected in 7 of 10 rabbits with osteomyelitis at 21 days postinfection, and these animals continued to display high antibody levels even at 59 days postinfection. In contrast, elevated levels of anti-cell-wall antibodies were only detected in 1 of 10 rabbits with subcutaneous abscesses. The enzyme-linked immunosorbent assay was found to be a rapid and sensitive serological technique for the detection of cell wall antibodies in this experimental osteomyelitis model and may be useful for the diagnosis of staphylococcal bone infections in humans.

Abscess↗