Biomedical subjects
J Jarvis
Publications and source records attributed to J Jarvis.
Changes in the natural anticoagulants following bone marrow transplantation.
The natural anticoagulants, protein C, protein S and antithrombin, were measured in 21 patients following bone marrow transplantation (BMT). The patients were divided into two groups, those with normal protein C concentration post-BMT and those with significantly reduced protein C concentrations; 12 cases fell into the second group. In addition there was an associated fall in protein S in this group of patients. In spite of the presumed hypercoagulable state only one patient developed overt veno-occlusive disease (VOD) of the liver and no other thrombotic events occurred. The fall in protein C and protein S was coincident with the peak incidence of VOD and is likely to be a contributing factor to the genesis of this condition. Only protein S measured pre-BMT was of predictive value in identifying patients likely to develop reduced levels of these anticoagulants post-BMT. Age, sex, diagnosis, type of conditioning and the pre-BMT measurement of protein C and antithrombin had no predictive value.
The scintigraphic and radiographic appearance of the ischiopubic synchondroses in normal children and in osteomyelitis.
Five cases of hematogenous osteomyelitis of the ischiopubic synchondrosis (IPS) were encountered among 180 patients with osteomyelitis treated over a 5-year period. Symptoms were poorly localized in all these IPS osteomyelitis patients. The IPS can normally show expansion and irregular mineralization radiographically and focal hyperconcentration of radiophosphates on scintigrams. Findings are frequently asymmetrical negating comparison with the contralateral side. In the cases of osteomyelitis, radiographs were abnormal at the time of presentation in only one of these five cases. In two of the four patients who had radionuclide bone scans, activity at the IPS exceeded that seen in a normal control population, but all showed loss of definition of the IPS and regional increased uptake permitting an early diagnosis.
The potentiation of the non-behavioural effects of amphetamine by carbon disulphide.
In agreement with the inhibition of dopamine-beta-hydroxylase by exposure to CS2, the extension of exposure time from 4 to 16 h increased dopamine concentrations in the hypothalmus and adrenals, and decreased noradrenaline concentration in the hypothalmus. The extension of exposure time also increased the toxicity of amphetamine. In conscious animals the stereotypic activity produced by 6.0 mg/kg and even that of 3.0 mg/kg amphetamine sulphate was suppressed by severe hyperthermia resulting in exhaustion, prostration and eventually death. A 16 h exposure to CS2 did not increase the lethal or hyperthermic effects of amphetamine in rats anaesthetized with 60 mg/kg sodium pentobarbitone. In fact the CS2 exposed rats became more hypothermic than non-exposed rats.
Use of sodium dodecyl sulfate-polymyxin B-sucrose medium for isolation of Vibrio vulnificus from shellfish.
The differential and selective sodium dodecyl sulfate-polymyxin B-sucrose medium (SPS) of Kitaura et al. (T. Kitaura, S. Doke, I. Azuma, M. Imaida, K. Miyano, K. Harada, and E. Yabuuchii, FEMS Microbiol. Lett. 17:205-209, 1983), which highlights alkylsulfatase activity, was evaluated for its potential use in the direct isolation and enumeration of Vibrio vulnificus from shellfish. V. vulnificus was detected by this method in six of nine shellfish samples collected from diverse geographic locales during the summer of 1986. Direct enumeration of V. vulnificus at 7.0 X 10(2) to 2.2 X 10(4) CFU/g of shellfish was achieved on SPS agar. All sample results were confirmed in parallel examinations by using conventional glucose-salt-Teepol (Shell Oil Co.) broth and alkaline peptone water enrichment with plating onto thiosulfate-citrate-bile salts-sucrose agar. Additionally, alkylsulfatase activity was evaluated in vitro for 97 strains representing 14 Vibrio spp. V. vulnificus and Vibrio cholerae-01 were the only species consistently found to possess this activity. The range of plating efficiencies for random V. vulnificus strains analyzed on SPS was 11 to 74% (mean, 39%). The use of SPS shows great promise for the study of shellfish and other environmental sources for V. vulnificus.
An immunoradiometric assay for human factor VIII/von Willebrand factor (VIII:vWF) using a monoclonal antibody that defines a functional epitope.
A murine monoclonal antibody has been produced (RFF-VIII:R/2) that binds specifically to human factor VIII-related antigen (VIII:RAg) in plasma and in vascular endothelial cells but has no reactivity with factor VIII procoagulant antigen (VIII:cAg). This antibody is a potent inhibitor of von Willebrand factor activity (VIII:vWF) in that it can totally neutralize ristocetin-induced aggregation of platelet rich plasma and inhibit platelet adhesion at high flow rates. RFF-VIII:R/2 can be used in a one-stage, fluid phase immunoradiometric assay that can detect VIII:RAg at concentrations of 0.001 u/ml. This method has been used to analyse plasma from patients with von Willebrand's disease (vWD). Results obtained in these patients showed a high degree of correlation between the monoclonally-defined epitope and VIII:vWF levels measured by ristocetin-induced aggregation of washed platelets. This correlation was maintained in those patients with the 'variant' types of vWD who exhibit highly disparate VIII:vWF and VIII:RAg levels when the latter is determined using polyclonal antisera. It appears that this monoclonal antibody recognizes a site on the VIII:RAg molecule which is associated with its interaction with the platelet membrane. Immunoradiometric assays using RFF-VIII:R/2 offer a simplified, reproducible means of detecting functionally-active VIII:RAg as an alternative or supplement to techniques involving platelet interactions.
Carbon disulphide exposure affects the response of rat adrenal medulla to hypothermia and hypoglycaemia.
The effects of hypothermia and hypoglycaemia on adrenal catecholamines and dopamine-beta-hydroxylase were compared in control and carbon disulphide (CS2) exposed rats 24 h after the last of ten daily 4 h inhalation exposures to CS2, 2 mg 1(-1) air. Animals were either kept in a cold room (0 degrees C) for 210 min with or without immobilization or were injected with insulin 100 u kg-1. Before these treatments CS2 exposed rats had more dopamine and less adrenaline in their adrenals than controls, and CS2 exposure also elevated the adrenal synthesis of catecholamines. Cold with immobilization or insulin treatment depressed the adrenal adrenaline content and increased the plasma concentrations of noradrenaline and adrenaline. There were no consistent differences between control and CS2 exposed rats. The adrenal dopamine content increased during cold exposure with immobilization or after insulin treatment both in CS2 exposed and control rats. The increase was smaller in CS2 exposed rats but the final dopamine values were nearly identical in the two groups. Exposure to cold (without immobilization) increased the adrenal dopamine content and the rate of catecholamine synthesis in control, but not in CS2 exposed rats. The increase in controls was less than the difference between the pre-cold exposure values of control and CS2 exposed rats. It is concluded that the elevation of adrenal dopamine content and catecholamine synthesis in CS2 exposed rats satisfy part of the demand placed on the adrenal medulla by hypothermia and hypoglycaemia. Consequently the changes induced by the latter treatments were smaller in CS2 exposed than in non-exposed rats. Moreover, when CS2 exposed rats were subjected to cold stress without immobilization their catecholamine synthesis was higher than the level measured in control rats after cold exposure.
Stimulation of dopamine-beta-hydroxylase in rat adrenals by repeated exposures to carbon disulphide.
The conversion of dopamine to noradrenaline, measured shortly after exposure to carbon disulphide, is reduced in the adrenals of rats. However, alongside this effect, carbon disulphide produces a gradual increase in the adrenal content of dopamine-beta-hydroxylase indicated by the increase of in vitro estimated enzyme activity and by the increased in vivo conversion of dopamine to noradrenaline observed 24 hr after the ninth exposure. Thus, after repeated exposures, the reduced rate of noradrenaline synthesis detectable immediately after the exposure alternates with the increased rate of synthesis.
Development and application of a monoclonal rat peroxidase antiperoxidase (PAP) immunocytochemical reagent.
Monoclonal antibodies are being increasingly used in immunocytochemistry but their localisation by the peroxidase antiperoxidase (PAP) procedure requires the use of rat or mouse PAP. In this paper we describe the development and application of a monoclonal rat PAP. This reagent has been used successfully for immunocytochemistry at light and electron microscopy level in combination with rat monoclonal antibodies against serotonin (5-HT), substance P and somatostatin. The monoclonal rat PAP has several advantages over conventional polyclonal rat PAP and is likely to be a valuable developing reagent in immunocytochemistry using rat monoclonal antibodies.
Characterization and immunocytochemical application of monoclonal antibodies against enkephalins.
Monoclonal antibodies were produced following immunization of mice with either [Leu5]enkephalin-bovine serum albumin or [Met5]enkephalin-keyhold limpet hemocyanin conjugates. Two monoclonal antibodies coded NOC1 and NOC2, respectively, were derived. These monoclonal antibodies did not discriminate between Leu- and Met-enkephalin in either radioimmunoassay or immunocytochemistry. NOC1 was characterized in detail. In radioimmunoassay NOC1 displayed about 40% crossreactivity with C-terminal extended Met-enkephalin hexapeptides and 7% with the extended heptapeptide (-Arg-Phe-OH), but did not recognize other endogenous peptides. In immunocytochemistry the NOC1 and NOC2 recognized all well-established "enkephalin immunoreactive sites," but they did not bind to areas known to contain beta-endorphin or high levels of pro-enkephalin. NOC1 was shown to be a suitable tool to demonstrate enkephalin immunoreactive sites by radioimmunocytochemistry utilizing both internally and externally labeled monoclonal antibodies.
Junctional diversity is essential to antibody activity.
Many mechanisms of antibody diversification have been shown to exist, including combinatorial pairings of heavy and light chains, the use of multiple gene segments (combinatorial diversity), and the imprecise joining of these gene segments (junctional diversity). The contributions of each of these mechanisms to functional antibody activity has not been fully explored, especially in the case of junctional diversity. A chain recombination experiment between an anti-arsonate monoclonal antibody and an anti-oxazolone molecule in which light chains differ essentially only at the V/J junctional position show that junctional diversity may play an important role in antigen binding.
Life change: adjusting to continuous ambulatory peritoneal dialysis.
A period of psychological adjustment occurs when a patient switches from hemodialysis to CAPD. The authors have identified four major categories of obstacles that patients must overcome in adjusting to CAPD and its self-care techniques. Ongoing group treatment is a valuable tool for patients in learning coping skills and alternative behaviors during this adjustment period. Members move through stages in the group, from dependence and a feeling of isolation to a stage of struggle for individuation and a work phase. It is in this work phase that group members show increased mutual concern and understanding, personal responsibility, honesty, individuation, a willingness to share and to be open, and coping skills. The value of this progression within the group is that what members learn there can be carried over to patients' lives outside the group. Group therapy can assist CAPD patients in coping with isolation, perceived abandonment by the medical environment, the resurgence of predialysis conflicts, a possible increase in libido, and new areas of family functioning. The process of individuation that occurs in the group has set patients on a course toward increased independent living, closer self-scrutiny, mutual education, vocational and recreational productivity, and an improved ability to deal with the stresses of end-stage renal disease.
Professional negligence and the occupational therapist.
This paper will attempt to clarify the meaning of negligence. The difference between the negligent acts of a layman and a professional are defined and compared, as well as professional and non-professional occupations. The method of determining the standard by which occupational therapists are measured is discussed as well as the points the Courts consider when the standard is breached and harm to the patient results. Consideration is given to the gradual shift of responsibility from the physician to the health care professional, the ensuing legal implications, and the division of responsibility for negligence. The position of occupational therapists employed by health care facilities, in relation to the liability of the employer and the practitioner are outlined. The points discussed are illustrated by cases from the British, Canadian and American Courts.
Monoclonal anti-A from a hybrid-myeloma: evaluating as a blood grouping reagent.
A monoclonal anti-A antibody has been evaluated and found suitable for use as a potent routine ABO grouping reagent, without the use of additives. The IgM anti-A (MH2/6D4) is secreted into the tissue culture supernatant by a permanent line of cloned cells derived by fusion of anti-A producing spleen cells and a mouse myeloma cell line. This is a cost-effective reagent which should reduce production costs by over 50%. This reagent has the advantages inherent in monoclonal antibodies among them the availability of unlimited quantities of unvarying antibody of known properties.
Staff appraisal.
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Pilot experiments with EB virus in owl monkeys (Aotus trivirgatus). II. EB virus in a cell line from an animal with reticuloproliferative disease.
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The effect of undernutrition and subsequent rehabilitation on the growth and chemical composition of the cerebellum, brainstem and fore-brain of the rat.
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