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Biomedical subjects

E A Sanders

Publications and source records attributed to E A Sanders.

At least 19 recordsLinked to original sources
PubMed1997

Clinical spectrum of X-linked hyper-IgM syndrome.

We report the clinical and immunologic features and outcome in 56 patients with X-linked hyper-IgM syndrome, a disorder caused by mutations in the CD40 ligand gene. Upper and lower respiratory tract infections (the latter frequently caused by Pneumocystis carinii), chronic diarrhea, and liver involvement (both often associated with Cryptosporidium infection) were common. Many patients had chronic neutropenia associated with oral and rectal ulcers. The marked prevalence of infections caused by intracellular pathogens suggests some degree of impairment of cell-mediated immunity. Although lymphocyte counts and in vitro proliferation to mitogens were normal, a defective in vitro proliferative response to antigens was observed in some patients, and additional defects of cell-mediated immunity may be presumed on the basis of current knowledge of CD40-ligand function. All patients received regular infusions of immunoglobulins. Four patients underwent liver transplantation because of sclerosing cholangitis, which relapsed in there. Three patients underwent bone marrow transplantation. Thirteen patients (23%) died of infection and/or liver disease. X-linked hyper-IgM syndrome, once considered a clinical variant of hypogammaglobulinemia, is a severe immunodeficiency with significant cellular involvement and a high mortality rate.

Bone Marrow Transplantation↗
PubMed1996

The risk of brain tumours in hereditary non-polyposis colorectal cancer (HNPCC).

Hereditary non-polyposis colorectal cancer (HNPCC) is known to be associated with several extracolonic cancers, e.g., cancers of the endometrium, stomach, urinary tract, small bowel and ovary. An association between HNPCC and brain tumours has also been reported, although previous risk analysis did not reveal an excess of this type of tumour. To determine whether HNPCC predisposes patients to brain tumours, we used risk analysis to compare families with HNPCC to those in the general population. Of the 1,321 subjects from 50 HNPCC families (with 60,237 person-years of follow-up) in the Dutch HNPCC Registry which satisfy the Amsterdam Criteria, 312 had colorectal cancer. The registry revealed 14 brain tumours in the HNPCC-patients and their first-degree relatives: 5 astrocytomas, 3 oligodendrogliomas, 1 ependymoma and 5 tumours for which a pathological report was not available. The relative risk of brain tumour in patients with HNPCC and their first-degree relatives was 6 times greater than in the general population (95% confidence interval, 3.5 to 10.1). After exclusion of the cases based only on family history, the relative risk was 4.3 (95% confidence interval, 2.3 to 8.0). Although the relative risk of brain tumour was increased, the lifetime risk was low (3.35%). Because it is not certain whether an improvement of the overall prognosis can be achieved by early diagnosis and intervention, and in view of the low lifetime risk, we do not recommend screening for brain tumours in HNPCC families.

Adolescent↗
PubMed1995

Surgical repair of traumatically induced collapsing trachea in an ostrich.

A region of tracheal collapse was identified by endoscopy after surgical repair of a traumatic injury to the neck in an ostrich. During periods of excitation, the ostrich would become dyspneic and collapse. A tracheal split-ring prosthesis was placed surgically to support the collapsing trachea. This technique, which is frequently used in dogs, is applicable for use in birds with collapsing trachea.

Animals↗
PubMed1995

Simple fed-batch technique for high cell density cultivation of Escherichia coli.

A simple fed-batch process for high cell density cultivation of Escherichia coli TG1 was developed. A pre-determined feeding strategy was chosen to maintain carbon-limited growth using a defined medium. Feeding was carried out to increase the cell mass concentration exponentially in the bioreactor controlling biomass accumulation at growth rates which do not cause the formation of acetic acid (mu < mu crit). Cell concentrations of 128 and 148 g per 1 dry cell weight (g l-1 DCW) were obtained using glucose or glycerol as carbon source, respectively.

Bacteriological Techniques↗
PubMed1995

Varicella-zoster virus assembly protein p32/p36 is present in DNA-containing as well as immature capsids.

Varicella-zoster virus (VZV) produces a group of nucleocapsid proteins (the p32/p36 nucleoprotein complex) which are the VZV analogues of the herpes simplex virus type 1 (HSV-1) and cytomegalovirus (CMV) assembly proteins. There are multiple components in the VZV p32/p36 complex, with major proteins of 32 and 36 kDa and minor proteins of 34 and 38 kDa. In HSV-1 the assembly proteins have been shown to be present in immature (B) capsids, but are removed prior to the formation of mature (C) capsids containing the viral DNA genome. Our work has shown that VZV produces capsids corresponding to the B and C forms. However, in contrast to HSV-1, VZV also produces "B/C" capsids that appear to contain both the assembly proteins and the viral DNA genome. Possible mechanisms for this are discussed. In addition, it was shown that VZV capsids appear to lack the 36 and 38 kDa proteins, and based on this observation we suggest that these may represent unprocessed forms of the assembly protein. In both HSV and CMV, a much larger, cross-reactive protein has been identified as the full-length product of the gene coding for the assembly protein. The homologous VZV gene (ORF 33) theoretically has the capacity to produce a 66 kDa protein. However, no such protein is readily apparent in VZV-infected cells. The presence of an immunoreactive 64 kDa protein was demonstrated in purified VZV capsids which may represent the full-length ORF 33 protein.

Antibodies, Monoclonal↗
PubMed1994

Effect of growth rate on stability and gene expression of recombinant plasmids during continuous and high cell density cultivation of Escherichia coli TG1.

Continuous and fed-batch cultures of recombinant Escherichia coli TG1 were carried out in order to study plasmid stability and recombinant product formation at different specific growth rates. The aprotinin::beta-galactosidase gene (Ap::lacZ) was placed under the control of two different promoter/repressor systems, the PLac/lacI (pPLac8) and the lambda PL/cIts857 (pPL6) system. The chemically (0.5 mM IPTG) induced gene expression exhibited higher product activity and plasmid stability than the thermally (40 degrees C) induced expression. In fed-batch cultivations with the more stable E. coli TG1(pPLac8) a special feeding strategy allowed bacterial growth with a constant growth rate mu for several hours up to high cell densities. The cloned gene product activity was noticeably effected by the specific growth rate and the cell density at the moment of induction. In particular, the enzyme activities passed a pronounced maximum value in dependence of the set growth rate. The results indicate that fed-batch cultivation strategies are well suited to produce recombinant gene products.

Escherichia coli↗
PubMed1994

Production of human parathyroid hormone by recombinant Escherichia coli TG1 on synthetic medium.

Production of human parathyroid hormone (hPTH) by Escherichia coli TG1:I52cIts was studied. The hPTH is expressed as a fusion protein under control of the bacteriophage lambda pR promoter. The organism grows on glucose/mineral salt medium and the expression of the gene product was investigated under variation of temperature and growth rate prior to and after induction. hPTH formation largely depends on cultivation temperature and is optimal for a temperature shift from 30 to 38 degrees C. Product expression is growth coupled and specific hPTH concentration is independent of growth rate. The results are compared with a previous study on E. coli N4830:pEX-PPTH grown on complex media.

Culture Media↗
PubMed1994

Deficiency of the beta subunit of the eighth component of complement presenting as arthritis and exanthem.

A 13-year-old boy presented with juvenile chronic arthritis of 6 months' duration. Antinuclear antibodies, anti-double-stranded DNA antibodies, and rheumatoid factor were not detected. Western blotting showed a deficiency of the beta subunit of the eighth component of complement. The same deficiency was present in the patient's sister. C8 beta deficiency is usually detected in individuals who survive meningococcal disease. There was no such history in this family. Juvenile chronic arthritis has not previously been described in patients with C8 beta deficiency.

Adolescent↗
PubMed1994

Evaluation of pulse oximetry in horses surgically treated for colic.

All 43 horses anaesthetised for colic surgery were premedicated with xylazine or diazepam. Anaesthesia was induced with guaifenesin and ketamine, horses were placed in dorsal recumbency and anaesthesia was maintained with isoflurane in oxygen and mechanical ventilation. Haemoglobin saturation readings (SpO2) were taken with a pulse oximeter and compared with computed haemoglobin saturation (SaO2) from arterial blood samples. Readings were taken over a range of SaO2 of 78-100%, mean arterial blood pressure ranged from 24 to 108 mmHg and PaO2 ranged from 53 to 490 mmHg. Analysis of 107 readings showed that SpO2 values predicted SaO2 but time, blood pressure and individual horse did not. Correlation coefficients between SpO2 and SaO2 were 0.85 for all values and 0.88 for values at 30 min. Values for bias and precision were calculated for all SpO2 values and for readings separated into 3 saturation groups: normal, low normal, and abnormal. The pulse oximeter tended to underestimate SaO2 at all times, and was less precise as the saturation decreased.

Analysis of Variance↗
PubMed1993

Studies on the production of human parathyroid hormone by recombinant Escherichia coli.

Expression of human parathyroid hormone, hPTH(-1-84), by Escherichia coli N4830:pEX-PPTH was studied in controlled bioreactors. The hPTH is expressed as a fusion protein under control of the bacteriophage lambda PR promoter. In batch runs, low biomass concentrations but high specific hPTH productivities were obtained with complex TY (bactotryptone and yeast extract) medium whereas high biomass concentration and low specific productivities were found when fructose was used instead of bactotryptone (YF medium). The preinduction temperature was always 30 degrees C; the temperature shift to induce production of fusion protein was varied from 36 to 42 degrees C. Formation of hPTH passed a pronounced maximum as a function of induction temperature when using YF medium. However, the optimum temperature shift was 38 degrees C for both media used. For this temperature increase both media yielded about the same volumetric hPTH productivity (approx. 30 mg hPTH/1 per hour). By applying a fed-batch strategy for the YF medium, the productivity of the recombinant protein could be further increased more than fourfold. Compared to shake-flask experiments, the hPTH yield could be increased by a factor larger than 20.

Biotechnology↗
PubMed1993

Control of microbial activity by flow injection analysis during high cell density cultivation of Escherichia coli.

The application of an automated flow injection analysis (FIA) system for on-line determination of microbial activity, during high cell density cultivations of Escherichia coli is reported. Based on a bioelectrochemical principle, the FIA method used a redox mediator (potassium hexacyanoferrate(III)) to facilitate electron transfer from the microorganisms to an electrochemical detector. Assays were carried out using a new sampling device which provided aseptic operation by use of a valve and chemical sterilisation. No sample dilution or pretreatment was necessary for biomass concentrations up to approx. 40 g l-1. The sample volume was 0.5 ml and the overall analysis time was 5 min. FIA signals were found to correlate well with the oxygen uptake rate (OUR). Changes in metabolic activity due to low substrate levels or high inhibitor concentrations in the cultivation medium became obvious from the FIA signals.

Bacteriological Techniques↗
PubMed1993

Diagnosing multiple sclerosis in childhood.

By presenting the cases of 3 children with laboratory supported definite multiple sclerosis [LSDMS] according to Poser's diagnostic criteria, we illustrate the difficulties of diagnosing MS in childhood. In search for appropriate diagnostic criteria for childhood MS, the literature on childhood MS is reviewed, and the 3 cases presented are compared with the 15 hitherto reported with the diagnosis LSDMS. Specific difficulties of diagnosing MS in childhood are discussed. They include history taking in children, the multiple differential diagnostic possibilities, and the various clinical presentations. Due to these specific difficulties in childhood MS, we conclude that a strict use of Poser's criteria is indispensable, especially in childhood MS.

Adolescent↗
PubMed1993

Repetitive injectable anesthesia in a 27-year-old horse.

A 27-year-old horse was anesthetized 3 times a week for 4 weeks, to facilitate cobalt therapy of a squamous cell carcinoma in the left paranasal sinus. Limitations of facilities required transport of the anesthetized horse to and from the cobalt therapy room, therefore, injectable anesthesia was used. Initially, the horse was preanesthetized with xylazine (at 1.1 mg/kg IV) and butorphanol (0.04 mg/kg IV). After 3 anesthetic episodes, the xylazine dose was reduced to 0.4 mg/kg IV and the butorphanol was deleted from the regimen. Tiletamine-zolazepam (1.1 mg/kg IV) was used for induction and maintenance of anesthesia (although on 2 occasions a bolus of ketamine was used to maintain immobility). The length of the procedure varied from 10-45 minutes, and the recovery times to sternal and standing varied from 23-76 and 55-105 minutes respectively. Although numerous complications might be expected given the age of this horse and the physiologic and metabolic demands of repetitive injectable anesthetics, none were observed.

Anesthesia, Intravenous↗
PubMed1992

[Good results in reoperation of recurrent radicular syndrome following surgery for herniated nucleus pulposus].

In the period 1985-1986 twenty-four patients with a recurrent lumbar disk herniation were subjected to surgery in the department of Neurosurgery in the Academic Medical Hospital of Utrecht. In 25% of these patients the second lumbar disk herniation was at the same level and side as the first one. Recurrence of the disk rupture at the same side and level as the first one occurred most often within two years after initial surgery. A recurrent slipped disk at different lumbar level occurred after a time interval of two years or more. Correct diagnosis depends on the results of imaging techniques. All reoperated patients did well after surgery and could return to their work or normal daily obligations.

Adolescent↗
PubMed1992

Psychiatric symptoms and mental changes as major features of multiple sclerosis.

A patient is presented with clinically and laboratory supported definite multiple sclerosis who developed severe depression followed by mental deterioration. Magnetic resonance imaging MRI demonstrated multiple hemispherical lesions. It is suggested that the psychiatric and cognitive signs and symptoms observed in this patient are due to severe cerebral demyelination.

Adult↗