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Biomedical subjects

A Jarvis

Publications and source records attributed to A Jarvis.

14 recordsLinked to original sources
PubMed1991

A novel approach to the assessment of drug compliance in the elderly.

A reliable drug history is not always available, and the constant accurate updating of patients' current medication at a Day Hospital may be difficult. This pilot study examined the use of a qualitative thin-layer chromatographic technique (Toxi-Lab system) applied to urine specimens in assessing drug compliance in the elderly. The system proved capable of detecting 36% of prescribed drugs in a group of elderly patients, and offers a novel and inexpensive approach to monitoring compliance with certain medications.

Aged↗
PubMed1990

X-ray microanalysis of teeth from healthy patients and patients with familial hypophosphatemia.

Energy-dispersive X-ray microanalysis was used to determine calcium/phosphorous (Ca/P) ratios in undecalcified teeth, and the sulfur (S) content of dentin of decalcified teeth from normal patients and patients with familial hypophosphatemia, in an attempt to determine the effect of phosphorus deficiency. The results showed that normal enamel has a slightly elevated Ca/P ratio compared to pure apatite. Enamel from a tooth of an untreated patient with hypophosphatemia exhibited a significantly higher Ca/P ratio than the normal teeth whereas enamel from teeth of an intermittently treated patient exhibited Ca/P ratios similar to pure apatite. Surprisingly, globular dentin in the same teeth showed a Ca/P ratio similar to that of globular dentin of the untreated tooth. The decalcified dentin from teeth of three hypophosphatemic patients and eight normal patients showed a S peak which varied widely in concentration. No detectable differences could be found between normal and diseased teeth.

Adolescent↗
PubMed1988

Detection of enkephalin-like immunoreactive material in human saliva.

1. A specific radioimmunoassay (RIA) was used to detect the presence of enkephalin-like activity in mixed saliva from healthy male and female human subjects, whose ages ranged from 20 to 30 and from 55 to 65 years. 2. Enkephalin-like immunoreactivity was measured in saliva from all subjects. Within the limits posed by the immunoassay no significant differences in levels were evident among the various groups. 3. The results of this study provide the first demonstration of opioid-like substances in saliva. 4. As the collection of saliva involves non-invasive techniques, this source may prove useful for monitoring enkephalin levels during various clinical procedures or experimental treatments.

Adult↗
PubMed1987

Microencapsulated tumor assay: new short-term assay for in vivo evaluation of the effects of anticancer drugs on human tumor cell lines.

A new in vivo has been developed for evaluating the antitumor activity of chemotherapeutic drugs. The assay is based on a microencapsulation technology developed by Damon Biotech, Inc., Boston, MA, which makes it possible to encapsulate human tumor cells in small (about 1 mm in diameter) microcapsules with semipermeable membranes. Microcapsules containing human tumor cells were injected i.p. into nude or C57BL/6 mice and drugs were administered i.v. The microcapsules were recovered at various intervals following treatment and determinations of drug effects were made based on the differences in the number of tumor cells recovered from the treated and nontreated animals. Using this assay we found that (a) encapsulated tumor cells grew better in the in vivo system than in vitro under the conditions tested; (b) drugs crossed the capsular membrane and killed or inhibited the proliferation of tumor cells; and (c) the antitumor effect was consistent with the relative therapeutic efficacy of drugs or level of resistance of tumor cells detected by other in vitro or in vivo tests. The tumor microencapsulation assay offers several properties which make it attractive for use in new drug development: (a) the antitumor activity of drugs can be tested against human tumor cells under conditions which provide for three-dimensional growth and in vivo supply of nutrients; (b) the sensitivity of tumor cells can be assessed following exposure to drugs at concentrations which are achievable in vivo; (c) compounds requiring in vivo metabolic activation can be tested; (d) the effect of each drug injection can be quickly evaluated; (e) inhibition of tumor cell proliferation versus cytoreductive effects of drugs can be discriminated; (f) the test is applicable to virtually all histological types of human tumor cells; and (g) the tumor microencapsulation assay is a short-term, simple, and relatively inexpensive assay.

Animals↗
PubMed1987

Cerebrospinal fluid levels of magnesium in patients with preeclampsia after treatment with intravenous magnesium sulfate: a preliminary report.

The purpose of this study is twofold: (1) to correlate magnesium levels of serum with those of cerebrospinal fluid in patients with preeclampsia receiving intravenous magnesium sulfate, and (2) to determine whether the magnesium ion crosses the blood-brain barrier in significant amounts after intravenous magnesium sulfate therapy. Of the 21 patients in whom spinal anesthesia was used for delivery, ten patients with preeclampsia with therapeutic serum magnesium levels made up the study group and 11 term nontreated normotensive gravid women served as controls. At the time of spinal anesthesia, a 1 ml aliquot of cerebrospinal fluid was obtained from each patient. The mean cerebrospinal fluid magnesium level for the control group was 2.56 +/- 0.19 mg/dl (range 2.2 to 2.8 mg/dl). For the preeclamptic group who received intravenous magnesium sulfate, the mean cerebrospinal fluid magnesium level was 3.04 +/- 0.12 mg/dl (range 2.9 to 3.2 mg/dl). Although only a small amount of magnesium crosses the blood-brain barrier after intravenous magnesium sulfate treatment, this increment is highly significant (p less than 0.001).

Adult↗
PubMed1980

Characterization of procoagulant activity produced by cultures of human monocytes and lymphocytes separated in colloidal silica-polvinylpyrrolidone gradients.

Human peripheral blood leucocytes were examined for their ability to synthesize procoagulant activity in tissue culture. A method was developed utilizing silica coated with polyvinylpyrrolidone (Percoll) to separate monocytes from lymphocytes prior to culture. Coagulation activity was demonstrated in all mononuclear cell cultures after 24 hours incubation. This activity was inhibited by phospholipase C which suggested that tissue thromboplastin was the major source of activity. Specific immunoradiometric assays failed to demonstrate synthesis of factor VIII related antigen (FVIIIRAG) or factor VIII coagulant antigen. The results indicate that under conditions of this study factor VIII was not synthesized in mononuclear cell cultures.

Cell Separation↗