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Biomedical subjects

J Miller

Publications and source records attributed to J Miller.

At least 739 records · Page 41Linked to original sources
PubMed1989

Maternal hemodynamic effects of uterine contractions by M-mode and pulsed-Doppler echocardiography.

Nineteen normotensive term gravid women were studied by M-mode and pulsed-Doppler echocardiography to noninvasively evaluate the hemodynamic consequences of uterine contractions on maternal left ventricular function. These laboring subjects were placed in the left lateral decubitus position with epidural labor anesthesia. Ejection fraction was not affected by firm contractions, although a small increase in left ventricular end-diastolic measurements was noted. There was a tendency for maternal heart rate to decrease (-5%); however, this trend was not statistically significant. A 16% increase in left ventricular stroke volume (75 +/- 15 to 89 +/- 17 ml) (p less than 0.001) was associated with an overall 11% augmentation of maternal cardiac output (6.31 +/- 1.79 to 7.12 +/- 1.93 L/min) (p less than 0.001). These findings support the hypothesis that uterine contractions increase maternal stroke volume through autotransfusion of uteroplacental blood and cardiac preload augmentation during normal labor.

Cardiac Output↗
PubMed1989

Suppression of immediate skin tests by ranitidine.

The suppression of immediate skin reactions to histamine and compound 48/80 by ranitidine, 150 mg every 12 hours for seven doses, was determined in a double-blind study in 23 subjects. Ranitidine compared to placebo produced a 22% suppression of the wheal-and-flare response to histamine (p less than 0.05) but only a 4% suppression of the wheal and flare with compound 48/80 (not significant). Although the suppression of the histamine skin test was statistically significant, this degree of suppression may be of limited clinical significance in allergy diagnostic testing.

Adult↗
PubMed1989

Who gets treated where. A study of patients transferred and not transferred from a consultation-liaison service to a general hospital psychiatry unit.

The decision to transfer a patient from a general hospital unit to a psychiatric unit is multifactorial. The most salient patient characteristics include the degree of dysfunctional behavior, the absence of social supports, and the presence of Axis II pathology. Severity of medical illness does not discriminate between the two groups. Awareness of these characteristics could aid physicians in formulating transfer decisions.

Age Factors↗
PubMed1989

Changes in the restriction endonuclease patterns of four modified-live infectious bovine rhinotracheitis virus (IBRV) vaccines after one passage in host animal.

Four genomically different bovine herpes virus 1 (BHV 1) vaccines were used to inoculate BHV 1-negative heifers. Restriction endonuclease analysis (REA) of virus isolates from animals during acute infection, after reactivation of virus from latency, and after reactivation followed by superinfection, showed that changes occurred in the BHV 1 genome after one passage in the host animal. Furthermore, the changes varied according to the tissue from which virus was isolated. Southern probe analyses identified the left terminus of the unique long fragment and the inverted repeats as regions of the genome where variability was most often observed. It was concluded that, when REA is used in the diagnostic differentiation of BHV 1 isolates, caution must be applied in the interpretation of results.

Animals↗
PubMed1989

Inhibition of acetyl- and butyrylcholinesterase and amylase release from canine pancreas.

There are two tissue-fixed cholinesterases in dog pancreas: acetylcholinesterase and butyrylcholinesterase. In the present experiments, an organophosphate that only inhibits butyrylcholinesterase (isopropylpyrophosphoramide, or iso-OMPA) was compared with echothiophate and a nonorganophosphate compound, physostigmine. The latter two agents inhibit both cholinesterases. Fresh canine pancreas from anesthetized dogs was minced into fragments and suspended in Eagle's solution gassed with 100% O2. Amylase release was measured by the Phadebas method. In 2-h dose-response studies, there was a fivefold increase in sensitivity to acetylcholine when fragments were preincubated 1 h with iso-OMPA. There was a 1,000-fold increase in sensitivity when fragments were preincubated for 1 h in echothiophate. Basal amylase release in incubates with echothiophate were also increased. In dose-response studies with CCK-8, iso-OMPA was without effect, but echothiophate treatment resulted in a greater total response to CCK-8. There was a corresponding increase in basal output with echothiophate alone. Physostigmine also potentiates the response to CCK-8. Cumulative responses up to 3 h with half-maximal acetylcholine or half-maximal CCK-8 doses showed enhanced total output in fragments preincubated with echothiophate (p less than 0.05). The enhancement effect was atropine-sensitive to hexamethonium ganglionic blockade. In calcium-free medium, the enhancement with echothiophate was greatly reduced but still present. Inhibitors of both cholinesterases in the pancreas cause a greater total amylase release to sub-maximal doses of acetylcholine and CCK-8 than agents that only inhibit butyrylcholinesterase. Though our data do not provide direct proof, the results could be explained by a greater accumulation of endogenous acetylcholine when both cholinesterases are inhibited.

Acetylcholinesterase↗
PubMed1989

Physical linkage of mouse lambda genes by pulsed-field gel electrophoresis suggests that the rearrangement process favors proximate target sequences.

The first complete map of a mammalian immunoglobulin gene locus is presented. Mouse lambda genes were mapped by pulsed-field gel electrophoresis. The gene order is V2-Vx-C2-C4-V1-C3-C1. The distance between V2 or Vx and the C2-C4 cluster is 74 or 55 kilobases (kb), respectively, whereas that between V1 and C3-C1 is only 19 kb; V2 and C3-C1 are at least 190 kb apart. Thus, the distances between the lambda subloci are inversely proportional to their frequencies of rearrangement. The related gene lambda 5 is not within the 500 kb of the lambda locus mapped here.

Animals↗
PubMed1989

Time course of appearance and disappearance of human mast cell tryptase in the circulation after anaphylaxis.

Tryptase, a neutral protease of human mast cells, is a potentially important indicator of mast cell involvement in various clinical conditions. The current study examined the time course of appearance and disappearance of tryptase in the circulation after an anaphylactic event and the stability of both endogenous and exogenous tryptase in terms of freeze-thawing and temperature. The peak level of tryptase after an experimentally induced systemic anaphylactic reaction occurred 1-2 h after the initiating bee sting in each of three subjects, in contrast to histamine levels which peaked at 5-10 min. In some cases elevated levels of tryptase may not be detected during the initial 15-30 min. Tryptase levels then declined under apparent first order kinetics with a t1/2 of approximately 2h. Similar disappearance kinetics were observed for two subjects presenting in the emergency room with immediate type reactions, one with severe asthma after indomethacin ingestion, the other with systemic anaphylaxis after a bee sting. Histamine levels declined rapidly and were back to baseline by 15-60 min. Measured levels of tryptase in serum or plasma were not diminished by up to four freeze-thaw cycles. Incubation of serum samples taken from subjects with elevated levels of tryptase at 22 and 37 degrees C indicated that greater than 50% of endogenous tryptase was still detected after 4 d. Purified tryptase added to serum or plasma and incubated as above was less stable: approximately 50% of exogenous tryptase in serum and approximately 15% in plasma was detected after 2d of incubation. Therefore, optimally samples should be stored frozen, but even those stored at room temperature for up to 4 d should be satisfactory. The best time to obtain samples for tryptase determinations is 1-2 h after the precipitating event, but depending on the magnitude of the initial response elevated levels of tryptase may be present in the circulation for several hours.

Adult↗
PubMed1989

Gardner syndrome. Early presentation with a desmoid tumor. Discovery of multiple colonic polyps.

A 14-year-old patient who was eventually found to have Gardner syndrome initially presented at the age of 3 years with a desmoid tumor involving the scalp. A careful review of the family history revealed a high incidence of colonic cancer, which prompted endoscopic evaluation of the patient. The discovery of adenomatous polyps in the colon confirmed the diagnosis of Gardner syndrome. In patients with hard or soft tissue tumors, the possibility of Gardner syndrome should be kept in mind, and a thorough family history taken. Early diagnosis may prevent malignant transformation of colonic polyps.

Adolescent↗
PubMed1989

The craniofacial resection--eleven-year experience at the University of Virginia: problems and solutions.

From September 1976 to December 1987, 25 patients underwent 27 craniofacial resections at the University of Virginia Health Sciences Center. Two of these patients, who had recurrent disease involving the cavernous sinus, underwent repeat, extended resections. Seventeen of the tumors were esthesioneuroblastomas. Only one patient had received no treatment before surgery. The complications of this surgical technique are reviewed. The most significant complications were neurologic problems and infection. Additional issues, such as the handling of the eye, lacrimal sac, and medial canthal ligament, are also reviewed.

Adolescent↗
PubMed1989

The control of attention by abrupt visual onsets and offsets.

A letter can be presented visually either by the abrupt appearance of lines that make up the letter (onset transient) or by the abrupt disappearance of extra lines from a form in which the letter is embedded (offset transient). Recent evidence from visual-search tasks has suggested that onset transients have absolute priority over offset transients with respect to the allocation of visual attention. Specifically, these studies have found that a single onset-transient target letter pops out of a background of offset-transient distractor letters (i.e., time to detect the target is independent of the number of distractors), which indicates that attention is automatically directed to the location of an onset-transient stimulus even when there are competing offset transients (Yantis & Jonides, 1984). Because of the way the offset letters were created, however, the total display change (number of offset line-segments plus number of onset line-segments) was greater for onset than for offset letters. Thus, onset targets might have popped out because they produced greater overall display changes rather than because they were the only letters with onset transients. In the present study, a figure that included more offset-transient line segments in the offset-transient letters was used. Under these conditions, onset-transient targets did not pop out of a background of offset-transient distractors. It is suggested that visual attention may be influenced by total display change and, therefore, that onset transients are not necessarily sufficient to control attention when there are many competing offset transients.

Attention↗
PubMed1989

A study of children with learning disabilities and sensorimotor problems or let's not throw the baby out with the bathwater.

The 1986 position statement by the Board of Trustees fo the Council for Learning Disabilities called for a moratorium on the measurement and training of perceptual and perceptual-motor function as a part of services for children with learning disabilities (LD). Estimates in the literature, however, indicate that approximately 13% of children with LD exhibit motor deficits. Such children with motor or perceptual-motor problems are of ten referred to occupational therapy and found to have sensory integrative (SI) dysfunction; subsequently, they are treated with techniques aimed at remediating perceptual or sensorimotor dysfunction. Because the results of research concerned with the efficacy fo sensorimotor therapy are inconclusive and incomplete at this time, the position statement may be premature. Occupational therapists, however, must be aware of the statement and respond appropriately. In order to respond, they must have a better understanding of the nature of this subgroup of children with LD who have motor problems. the purpose fo this study was to assist in the definition of this population. Eighty children with LD between 5 years and 8 years 11 months were examined. They had been referred for occupational therapy at six centres in Southern Ontario. Results indicated that these children were similar to other children with LD in terms of gender and IQ distribution, developmental history, and academic achievement. The study population, however, tended to have less generalized emotional/behavioral disorder than the general population with LD. As expected, these children also had major deficits in gross and fine motor performance. A focus of the paper is on the importance of sensorimotor deficit for learning and self-concept in the child. Implications for both the position statement and practice and research in occupational therapy are discussed.

Journal Article↗
PubMed1989

Posttransplant hyperglycemia. Increased incidence in cyclosporine-treated renal allograft recipients.

The incidence of posttransplant diabetes mellitus (PTDM) was compared in two groups of renal allograft recipients. These were all nondiabetic patients who had been transplanted between 1979 and 1987 and received either azathioprine-methylprednisolone (group 1) or cyclosporine-methylprednisolone (group 2) therapy as maintenance immunosuppression. The incidence of PTDM in group 1 was 9.1% vs. 18.6% in group 2 (P less than .05). The mean daily dose of methylprednisolone during the initial 2 months posttransplant was not greater among the PTDM patients of groups 1 or 2. Cyclosporine levels and mean daily CsA doses during the initial 2 posttransplant months were also not different among the CsA-PTDM and euglycemic CsA patients. Posttransplant diabetes mellitus occurred rapidly (less than 2 months) and required insulin therapy in the majority of cases. Increased age (greater than 40 years) was associated with a higher risk for PTDM, however, the greater incidence accompanying increased body weight only approached significance. Patient gender and donor source were not associated with significant risk for PTDM. The development of PTDM was accompanied by a significant decrease in graft survival at 3 years in the entire PTDM population and at 4 years in the CsA-PTDM subgroup. Actuarial patient survival was not adversely affected. The current study suggests that CsA may be diabetogenic when administered with methylprednisolone to renal allograft recipients. The adverse effect on allograft survival requires further investigation. These results may also have important implications for pancreatic and islet cell transplantation.

Actuarial Analysis↗