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J R Baker

Publications and source records attributed to J R Baker.

At least 181 records · Page 10Linked to original sources
PubMed1990

Characterization and measurement of immunoglobulins in the grey seal (Halichoerus grypus).

Immunoglobulin concentrations were measured in the serum and colostrum of adult and pup Grey seals from North Rona in the outer Hebrides and the Isle of May in the Firth of Forth. IgG was shown to be the main immunoglobulin and two subclasses were identified. Serum immunoglobulin content was low in the week-old pups and increased up to 5 weeks, although it remained substantially lower than in the adults. Colostral immunoglobulins were high and cannot explain the low values in the pup serum. It is considered that the increased opportunistic infections seen in Grey seal pups may be related to this low immunoglobulin status.

Animals↗
PubMed1990

Fructosamine compared with a glucose load as a screening test for gestational diabetes.

Five hundred seven women were screened for gestational diabetes between 20-36 weeks' gestation. All received a 100-g glucose (polycose) load at 28 weeks with measurement of plasma glucose 1 hour later. Fructosamine levels were measured at 4-week intervals from 20-36 weeks. At 36 weeks, a full 100-g 3-hour glucose tolerance test was performed on all subjects. Eighteen women were diagnosed as having gestational diabetes. The glucose load had a sensitivity of 81% in detection of gestational diabetes, compared with 50% for fructosamine at 36 weeks. Fructosamine is not useful as a screening test for gestational diabetes as currently defined.

Diabetes Mellitus↗
PubMed1990

Chondroitin sulfates in developing mouse tooth germs. An immunohistochemical study with monoclonal antibodies against chondroitin-4 and chondroitin-6 sulfates.

The role of glycosaminoglycans and proteoglycans during ontogenesis is not known. The developing tooth offers a potentially important model for studies of structure-function relationships. In this study, we have analysed the temproal and spatial expression of chondroitins of differing sulfation patterns in embryonic molars and incisors. For this purpose, we have used monoclonal antibodies (Mabs) specific for unsulfated, 4-sulfated, and 6-sulfated forms of chondroitin in conjunction with indirect immunofluorescence or immunoperoxidase labeling. Unsulfated chondroitin was not detected in embryonic teeth. Chondroitin 4- and chondroitin 6-sulfates were present in the stellate reticulum but otherwise they were confined to the dental mesenchyme. The 3B3 and MC21C-epitope, which are markers of 6-sulfated chondroitin, were uniformly distributed in the dental mesenchyme during the bud stage; they disappeared from the dental papilla of the cusps and of the anterior region of the incisor as development proceeded. These epitopes were absent from the basement membrane and from the predentin. In the odontoblastic cell lineage, the 3B3 and MC21C-epitopes were detected only between preodontoblasts at an early stage of differentiation. The monoclonal antibody 2B6 served as a probe to localize chondroitin 4-sulfate. This glycosaminoglycan was detected as early as the dental lamina stage but its expression was restricted to the basement membrane of the teeth until the late bell stage. After the onset of cusp formation, strong staining was also observed over the occlusal region of the dental papilla while the cervical region of the dental papilla remained 2B6-negative. Incisors at the bell stage exhibited a decreasing gradient of immunostaining by 2B6 from their anterior region to their posterior end. The extracellular matrix surrounding preodontoblasts reacted with 2B6 and the predentin, produced by the odontoblasts, was also intensely labeled with this antibody. Comparison between immunostaining with 3B3 and 2B6, on consecutive sections revealed a mutually exclusive pattern of distribution of the corresponding epitopes during odontogenesis. Furthermore, in the continuously growing incisor, a striking positive correlation was found between the immunostaining patterns produced by 3B3 and MC21C and the mitotic indices along the anterior-posterior axis of the tooth. Hence, sulfation of chondroitin seems developmentally regulated. We postulate that changes in the sulfation pattern of chondroitin might play a role in ontogenesis by locally altering the functional properties of the extracellular matrix.

Animals↗
PubMed1990

Hypersensitivity reactions from taxol.

Taxol is an antitumor agent in clinical trial that has been shown to have activity against advanced ovarian carcinoma and melanoma. Hypersensitivity reactions (HSRs) have been one of the toxicities observed with administration of this drug. Of 301 patients treated, 32 patients have had definite (27 patients) or possible (five patients) hypersensitivity reactions to taxol. All but one patient had the reaction from the first or second exposure to this agent. Reactions occurred at a variety of doses and were characterized most frequently by dyspnea, hypotension, bronchospasm, urticaria, and erythematous rashes. Thirteen (41%) patients had received premedication designed to prevent such toxicity; nevertheless, they sustained HSRs. Prolonging the drug infusion appears to have somewhat reduced, but not obviated, the risk of HSRs. The cause (taxol itself or its excipient Cremophor EL; Badische Anilin und Soda-Fabrik AG [BASF], Ludwigshafen, Federal Republic of Germany) and the mechanism of these reactions to taxol are unknown. We provide guidelines to prevent or minimize such toxicity and treat reactions if they still occur.

Adult↗
PubMed1990

Regulated changes in chondroitin sulfation during embryogenesis: an immunohistochemical approach.

Chondroitin sulfate proteoglycans, which represent the main class of nonfibrous macromolecules found in the extracellular matrix of connective tissues, have been implicated in the control of a variety of cell activities during ontogenesis. The respective contributions of the chondroitin sulfate chains and of the protein moiety of the proteoglycan in morphogenesis and cytodifferentiation are not known. In this context, monoclonal antibodies identifying specific chondroitin sulfate chains are interesting new tools. A panel of well characterized monoclonal antibodies recognizing distinct epitopes present only in chondroitin sulfate chains was used in conjunction with immunohistochemical techniques for the purpose of identifying and mapping chondroitin sulfate isoforms during development in the mouse and rat fetus. Expression of chondroitin sulfate isoforms occurred in the tissues according to specific spatio-temporal patterns, suggesting that chondroitin sulfates differing in sulfation position and degree perform distinct functions in development.

Animals↗
PubMed1990

Transplantation in the military: state of the art--a progress report from the Army-Navy Transplant Program.

The commitment to clinical transplantation services by the Army and Navy is now in its third decade. Located at the Walter Reed Army Medical Center, the Army-Navy Organ Transplant Service has been staffed and led by some of the most prominent transplant surgeons in America. Military beneficiaries are eligible for evaluation and care regardless of their geographic assignment or residence. Principally a renal transplant clinical service, the Organ Transplant Service also gives support to patients with heart, liver, and pancreas grafts. Organs for transplant are largely (85%) from the civilian sector, although the Department of Defense has officially encouraged organ donation. Research, scientific publication, protocol development, teaching, and interaction with reserve components have been major facets of the Organ Transplant Service. Clinical outcome in renal transplantation at the Army-Navy Unit is comparable to that at the best civilian units: 2-year graft and patient survival 81% and 98%, respectively. These superior clinical results and the major roles that the Army-Navy Transplant Service have played make continued support and expansion of military transplantation compelling.

Hospitals, Military↗
PubMed1989

Natural causes of death in non-suckling grey seals (Halichoerus grypus).

Thirty-four grey seals which died of natural causes were examined. They ranged in age from aborted fetuses to adults, but suckling pups were excluded from the study. The commonest primary cause of death was pneumonia and a variety of parasitoses occurred as secondary lesions.

Abortion, Veterinary↗
PubMed1989

Significant DQw1 association in achalasia.

Achalasia is a neuromuscular disorder of the esophagus with unknown etiology. There have been suggestions that this disorder is immunologically mediated. To examine this possibility, HLA phenotyping was prospectively performed on 40 patients with documented achalasia (24 Caucasian, 16 blacks). Results showed a positive association for the class II HLA antigen, DQw1, with 83% of Caucasians (P less than 0.02) and 86% of blacks having the antigen (NS). The relative risk for developing achalasia with the presence of DQw1 was 4.2 in Caucasians and 3.6 in blacks. A negative correlation for the DRw53 antigen was noted in Caucasian patients with a relative risk of 0.23. These results indicate an immunogenetic association for achalasia and provide insight into the pathogenesis of this disorder.

Adult↗
PubMed1989

Binding of thyrotropin to selected Mycoplasma species: detection of serum antibodies against a specific Mycoplasma membrane antigen in patients with autoimmune thyroid disease.

Radiolabeled human (hTSH) and bovine (bTSH) thyroid stimulating hormone was shown to bind to five species of Mycoplasma, the wall-less prokaryotes. The maximum binding capacity of 125I-bTSH to these five species was about 7.9 x 10(-13) moles-1.4 x 10(-12) moles for 50-100 micrograms protein with dissociation constants of approximately 1.7 to 2.2 x 10(-7)M. Approximately 50% of the 125I-bTSH binding was displaced by excess, unlabeled bTSH or hTSH, but labeled bTSH was not effectively displaced by growth hormone, LH, FSH, prolactin, or the beta subunit of hTSH, FSH and LH. Antisera prepared against Mycoplasma gallisepticum and Mycoplasma pneumoniae bound to human thyroid membranes and guinea pig fat cells, suggesting that receptors on human thyroid tissues and on Mycoplasma cells may have similarities in antigenicity. These findings were substantiated by the occurrence of TSH binding to Mycoplasma antisera. Further, sera from three of six patients with Graves' disease containing antibodies to thyroid tissues also reacted to a 108 Kd polypeptide of Mycoplasma gallisepticum.

Animals↗
PubMed1989

Immunoglobulin composition of three commercially available intravenous immunoglobulin preparations.

To evaluate whether significant differences in immunoglobulin composition exist among the three commercially available intravenous immunoglobulin (IVIG) preparations, we compared three of these products in terms of their quantitative immunoglobulin concentration, IgG subclass concentration, and the presence of IgG aggregates. Three different lots were tested for each of the IVIG formulations, and the IgG subclass assays were performed by three different laboratories. Differences were found among the three formulations in subclass concentration and aggregate content. Sandoglobulin (Sandoz Pharmaceuticals, East Hanover, N.J.) contained a significantly higher amount of IgG2 (p less than 0.002) compared to the other formulations. All the formulations tested were found to be deficient in IgG4 relative to the World Health Organization standards, with Gammagard (Hyland Therapeutics, Glendale, Calif.) demonstrating only negligible amounts. Immunoglobulin aggregate content was different among manufacturers with Gamimmune N (Cutter Biological, Berkeley, Calif.) containing the highest amount of monomer IgG (99.8%). Significant differences were found in the subclass results obtained by the ICN ImmunoBiologicals assay (Lisle, Ill.), compared to the two reference laboratories. This difference among the subclass assays raises the question as to the use of these assays in the evaluation of patients with suspected subclass deficiencies. The differences in subclass concentration and aggregate content in IVIG preparations were great, and future clinical trials with these formulations would be indicated to determine the clinical significance of these findings.

Chromatography, High Pressure Liquid↗
PubMed1989

A non-linear multi-criteria programming approach for determining county emergency medical service ambulance allocations.

In this paper an integer, non-linear mathematical programming model is developed to allocate emergency medical service (EMS) ambulances to sectors within a county in order to meet a government-mandated response-time criterion. However, in addition to the response-time criterion, the model also reflects criteria for budget and work-load, and, since ambulance response is best described within the context of a queueing system, several of the model system constraints are based on queueing formulations adapted to a mathematical programming format. The model is developed and demonstrated within the context of an example of a county encompassing rural, urban and mixed sectors which exhibit different demand and geographic characteristics. The example model is solved using an integer, non-linear goal-programming technique. The solution results provide ambulance allocations to sectors within the county, the probability of an ambulance exceeding a prespecified response time, and the utilization factor for ambulances per sector.

Ambulances↗