Search PubMed⌕ Search

Biomedical subjects

R Miller

Publications and source records attributed to R Miller.

At least 541 records · Page 30Linked to original sources
PubMed1991

Comparative susceptibility of anopheline mosquitoes in Rondonia, Brazil to infection by Plasmodium vivax.

Seven anopheline species from Costa Marques, Rondonia, Brazil were compared with Anopheles darlingi for susceptibility to infection by Plasmodium vivax. Laboratory-reared F1 progeny of field-collected An. darlingi and the test anopheline species were fed at the same time on the same patients, all of whom had gametocytes in peripheral blood before treatment. Mosquitoes were dissected on day 8 after infection for oocysts and on days 14-16 after infection for sporozoites. The mean numbers of P. vivax oocysts and the percent of salivary gland infections for An. darlingi and An. deaneorum were similar and far exceeded those found in the other anopheline species tested. Anopheles albitarsis and An. mediopunctatus were less susceptible to infection by oocyst measurements than An. darlingi. However, for oocyst-infected An. albitarsis and An. mediopunctatus, the percent of mosquitoes with salivary gland infections and the numbers of sporozoites in the salivary glands were similar to An. darlingi. Anopheles triannulatus and An. oswaldoi were both susceptible to P. vivax infection, but the sporozoite infection rates and the numbers of sporozoites observed in the salivary glands were very low. Anopheles braziliensis and An. benarrochi both developed oocysts, but were never observed to have sporozoites in the salivary glands. These studies implicate some anopheline species as potential malaria vectors, but also show that species previously incriminated by ELISA techniques are not vectors of malaria parasites in Costa Marques, Rondonia, Brazil.

Animals↗
PubMed1991

Disposition of cocaine in pregnant sheep. II. Physiological responses.

We studied maternal and fetal blood pressure, heart rate, arterial blood gases and fetal behavioral state alterations in response to maternally administered cocaine hydrochloride in 11 pregnant sheep. Cocaine administration to the ewe caused a dose-dependent increase in maternal blood pressure and heart rate and in fetal blood pressure, and a decrease in fetal arterial oxygen tension. In the ewe, blood pressure changes corresponded linearly to dose administered (r = 0.88, p less than 0.001). Blood pressure changes were correlated to peak plasma cocaine concentration in the ewe (r = 0.52, p less than 0.01) and in the fetus (r = 0.43, p = 0.05). In addition, in 7 of 8 fetuses which had entered rapid eye movement (REM) sleep within 5 min of maternal cocaine administration, REM sleep was abruptly terminated either by the cocaine, fetal hypoxia or some other nonspecific event caused by the maternal cocaine administration. Maternal cocaine administration causes maternal and fetal hemodynamic alterations that have potential adverse effects in pregnancy.

Animals↗
PubMed1991

Technical and other considerations in identifying operations research problem areas, selecting topics, and designing studies.

Problem identification and OR study topic selection are the foundations upon which the success of the entire OR process depends. Both technical and nontechnical issues impinge on these early stages of project development and must be dealt with simultaneously. This paper has proposed a set of guidelines or questions for weighing the technical considerations of OR, that is, for selecting relevant and salient problems that have competing solutions implementable through administrative action. However, it is not as easy to come up with a similar set of guiding questions for judging the nontechnical, often political considerations that usually result in compromises in project development. It may be hoped that further discussion of these issues will lead to the development of clear and useful guidelines.

Clinical Protocols↗
PubMed1991

Mycobacterium avium-intracellulare infection in the acquired immunodeficiency syndrome.

Disseminated infection with Mycobacterium avium and M. intracellulare (MAI) is increasingly recognized as a significant contributor to both increased illness and death in patients with acquired immunodeficiency syndrome. Early reports of treatment of MAI were disappointing but recent studies have shown that combination antimycobacterial therapy may provide symptomatic relief and an improvement in mycobacteraemia.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Determination of hepatitis B virus DNA in serum using the polymerase chain reaction: clinical significance and correlation with serological and biochemical markers.

Sera from 98 patients with various stages of chronic hepatitis B virus infection were studied to determine the clinical significance of hepatitis B virus DNA in serum detected by the polymerase chain reaction. Patients were divided into three groups according to their HBsAg and HBeAg status. Group I (n = 31) had detectable HBsAg and HBeAg, group II (n = 46) had HBsAg but not HBeAg and group III (n = 21) consisted of patients who were once chronic hepatitis B virus carriers but had lost HBsAg during follow-up. Group I patients usually had significant liver disease (raised serum aminotransferases), had higher titers of HBsAg and had been infected with hepatitis B virus for a shorter period than patients in the other two groups. All patients in group I had hepatitis B virus DNA detectable by polymerase chain reaction and 94% had sufficient hepatitis B virus DNA present for detection by dot-blot hybridization. Group II patients had lower mean serum aminotransferase activities and titers of HBsAg than those in group I. Serum hepatitis B virus DNA was detectable by polymerase chain reaction in 78% but in only 30% of group II patients by dot-blot hybridization. Group II patients who did not have hepatitis B virus DNA detectable by polymerase chain reaction had mean serum aminotransferase levels within the normal range and had a younger mean age than those with hepatitis B virus DNA. Group III patients generally had no evidence of active liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Advances in pediatric emergency department procedures.

Pediatric procedures in the Emergency Department typically involve techniques for stabilization, evaluation, and treatment of the child. This article considers indications and techniques for vascular access, lumbar puncture, arterial lines, pulse oximetry, and urine collection. Multiple routes of medication administration and pain management modalities also are reviewed.

Catheters, Indwelling↗
PubMed1990

The relevance of a First-World therapeutic drug monitoring service to the treatment of epilepsy in Third-World conditions.

In May 1988 a Therapeutic Drug Monitoring (TDM) service for anti-epileptic drugs was established at Prince Mshiyeni Memorial Hospital. This service was offered as a multidisciplinary team approach involving sisters, doctors, social workers and pharmacists at an epilepsy clinic. Statistics gathered over a 13-month period showed that: (i) epileptic patient numbers increased from 52 to 211 per 4-week cycle, while patients requiring TDM decreased from 40 to 20 per cycle; (ii) phenytoin was the most frequently prescribed anticonvulsant, followed by carbamazepine and phenobarbitone, throughout the period; (iii) TDM did not alter prescribing patterns--approximately 90% of patients were on monotherapy at the beginning and at the end of the assessment period; (iv) 471 serum levels were measured in 280 patients over 13 months. Phenytoin serum levels constituted the majority (53%) followed by carbamazepine (33%), phenobarbitone (12%) and valproate (2%); (v) of the levels measured in 24 patients taking phenytoin 300 mg/d who were experiencing neither seizures nor side-effects, 38% of levels were in the potentially toxic range; and (vi) well-controlled patients increased from 36% in the first cycle to 60% in the last cycle. A TDM service is very useful in a Third-World setting and can assist in conserving scarce sources provided it is utilised within a holistic treatment framework.

Adolescent↗
PubMed1990

Interleukin 2 and lymphokine-activated killer cell therapy: analysis of a bolus interleukin 2 and a continuous infusion interleukin 2 regimen.

Several groups have described the efficacy of interleukin 2 (IL-2) plus lymphokine-activated killer (LAK) cells in the treatment of cancer patients with significant response rates noted in patients with renal cell cancer and malignant melanoma; however, the optimum regimen remains undefined. The Biological Response Modifiers Program of the National Cancer Institute conducted two consecutive Phase I/II studies evaluating the toxicity and clinical efficacy of different methods of IL-2 and LAK cell therapy. In the first trial, we modified the standard Rosenberg regimen by decreasing the duration of priming in an attempt to reduce the toxicity related to this phase of the therapy and thereby administer more IL-2 doses with the LAK cells. In the second trial, we used a continuous i.v. infusion IL-2 regimen and altered both the leukapheresis procedure and the LAK cell culture techniques based on our in vitro and preclinical studies suggesting that 2-day LAK cells were superior. Thirty cancer patients received i.v. bolus IL-2 at 100,000 units/kg every 8 h for 3 days during priming and for 5 days during LAK cell administration. A second group of 22 cancer patients received IL-2 by continuous i.v. infusion at 3 x 10(6) units/m2 for 5 days during priming and an additional 5 days of IL-2 with the LAK cell phase of the treatment. The timing of the start of the leukapheresis procedures, their duration and number, and the LAK cell culture techniques differed in the two trials. Overall, 52 patients with various cancers were treated. The toxicities associated with each regimen were similar to those seen in other IL-2 plus LAK cell trials. Four patients (one each with melanoma and diffuse large cell lymphoma and two with renal cell cancer) exhibited partial responses lasting 2, 4, 10, and 15+ mo. Serial tumor biopsies from treated patients demonstrated that therapy can produce a marked mononuclear cell infiltrate and an increase in HLA-DR expression on tumor cells. There was no difference in the overall response rate between the two regimens, but toxicity was less with continuous i.v. infusion IL-2. The 5-day continuous i.v. infusion regimen resulted in significantly higher rebound lymphocytosis, cell yield from leukapheresis, and number of LAK cells harvested from culture.

Adolescent↗
PubMed1990

Therapeutic drug monitoring in a paediatric epilepsy clinic.

In 1988 a therapeutic drug monitoring programme for anticonvulsants was introduced in the paediatric neurology clinic at King Edward VIII Hospital, Durban. Although before this serum drug levels were routinely measured, the new approach involved the application of clinical pharmacokinetics to the results so that an individualised drug profile was available for use in conjunction with clinical evaluation at the patient's next visit. Case reports are presented to illustrate the value of using serum levels in this way. Of the 58 patients entered into the study in the course of 1 year, 32 (55%) benefited from the monitoring programme in that the pharmacokinetic report contributed to a dosage adjustment that resulted in a reduction in either seizure frequency or side-effects. The greatest value of the programme proved to be in rationalizing the use of phenytoin. Because of wide inter-patient variation and non-linear kinetics, it is difficult to establish an optimum maintenance dose for this drug. The individualised dose achieved in the present study using Bayesian forecasting resulted in improved seizure control in 10 of the 11 patients (91%) receiving phenytoin.

Anticonvulsants↗
PubMed1990

The effect of independent practice association plans on use of pediatric ambulatory medical care in one group practice.

We compared the use of pediatric ambulatory medical care of 640 children who switched from a traditional Blue Cross plan to more comprehensive independent practice association plans with that of matched patients who remained with Blue Cross in one large, suburban pediatric practice in Rochester, NY. A quasi-experimental, retrospective cohort design was used. Use of pediatric ambulatory medical care by patients in the independent practice association plan and control patients was determined by medical chart review for 1 year before and 1 year after each patient's switch. During the baseline year, patients who would join the independent practice association plan already had 19% more acute-illness visits than control patients. During the second year, patients in the independent practice association plan averaged 42% more acute-illness visits, 22% more well child-care visits, 93% more chronic-illness visits, 27% more after-hours visits, 53% more weekend visits, 185% more laboratory studies, and 70% more referrals. The shift toward independent practice association plans in this open-market setting increased use of ambulatory medical care for pediatric patients.

Ambulatory Care↗
PubMed1990

The clinical course of multiple sclerosis during pregnancy and the puerperium.

Eight women with multiple sclerosis were followed up through pregnancy. Clinical conditions, T-cell subsets, and levels of immunoactive pregnancy-associated proteins were measured twice during the pregnancy and twice during the first postpartum year. None of the women's conditions worsened during pregnancy, although one woman reported a slight increase of symptoms. Six of the eight women experienced relapses within the first 7 weeks after delivery. The number and percent of CD8 suppressor T cells were lower, and the CD4 helper-CD8 suppressor T-cell ratio was higher in the pregnant patients with multiple sclerosis compared with pregnant control women throughout pregnancy and the first 6 months post partum. There was no evident relationship between these parameters and clinical disease activity. Levels of alpha-fetoprotein, alpha 2-pregnancy-associated glycoprotein, and pregnancy-associated plasma protein A, all immunosuppressive proteins associated with pregnancy, were not significantly different in pregnant patients with multiple sclerosis and pregnant controls without multiple sclerosis. The study suggested that the risk of clinical relapse after delivery may be higher than has been reported previously. Furthermore, although there were differences in suppressor T cells, they were not predictably linked to changes in clinical disease activity.

Adult↗
PubMed1990

Statistical comparison of two methods of clinical measurement.

The comparison of two measurement techniques, neither of which can be regarded as being a 'gold standard', is fundamental to much basic research. This apparently simple problem raises many statistical difficulties, which are reviewed in this paper in the context of anorectal manometry. It is concluded that a recently developed approach focusing on the agreement between the two techniques is far superior to the more conventional approach based on correlation. However, until the benefits of the new analysis are more widely recognized (and it is hoped that this paper is a step towards that goal), it is argued that it is useful to present both analyses in such comparisons of measurement techniques.

Air↗
PubMed1990

Ambulatory anorectal physiology in patients following restorative proctocolectomy for ulcerative colitis: comparison with normal controls.

The purpose of this study was to determine the manometric activity of ileoanal W pouch reservoirs following restorative proctocolectomy for ulcerative colitis and to compare the results with normal controls. Thirty-one studies were carried out; there were 15 controls (median age 52 years (range 29-80 years), 10 men, 5 women) and 16 pouch patients (median age 40 years (range 28-52 years), 13 men, 3 women). Mid-anal sphincter pressure and 'rectal' pressure were measured with a microtransducer catheter. The signals were digitalized and recorded in a portable electronic memory for later computer display and analysis. The system allowed the study of patients with minimal constraints while fully ambulant. The frequency of sampling (rectal pressure greater than or equal to sphincter pressure), sensation of flatus present and flatus being passed were 7(1-41), 3(1-7) and 1(0-3.5) per hour in the normal controls and 0(0-3), 0(0-1) and 0(0-1) respectively per hour in the pouch patients (P less than 0.001). Compared with the highly dynamic nature of the anorectum in normal subjects the patients with a pouch had very little activity. The sensation of pouch filling and the desire to defaecate were noted on 12 occasions and in six were associated with a rise in pouch pressure greater than 20 mmHg. One patient had nocturnal soiling and this was the only patient in whom frequent pouch contractions were noted. The results suggest that ileoanal pouch motility is usually quiescent and that incontinence in this group may be related to increased pouch activity.

Adult↗
PubMed1990

A private idiotype can become recurrent through genetic recombination and gene(s) unlinked to the Igh locus governs its expression.

Any immune response is characterized by its idiotypic profile. Two different kinds of idiotype (Id) have been described. Private Id are restricted to a few individuals from a species while recurrent Id appear in a large majority of individuals from the same species immunized with the same antigen. We describe, in this report, an experimental model whereby a private Id can become recurrent through genetic recombination. The immune response of A mice against the hapten arsonate is characterized by a recurrent Id called cross-reactive idiotype A (CRIA). A strongly CRI, called CRIA-like, can be occasionally detected in some BALB/c mice (5% to 10%) immunized with arsonate. Molecular studies show that CRIA and CRIA-like antibodies have highly homologous D segments and identical light chains. By contrast, their VH segments are vastly dissimilar. We have examined the anti-arsonate response of inbred strains of mice whose Igh loci are recombinant between those of A/He and BALB/c. Interestingly, we have observed that the CRIA-like Id which is private in BALB/c becomes recurrent in the AXC-1 strain which harbors the VH genes from BALB/c, the DH and CH genes from A/He. Structural studies demonstrate that highly homologous, VH, VL and D segments are used in BALB/c and AXC-1 mice. The basis for this differential expression of highly similar genes could be linked to the DH locus. However, F1 mice stemming from the cross between AXC-1 and BALB/c do not express the Id. The backcross analysis shows that the non-expression of the Id in F1 mice depends on genes unlinked to the Igh locus.

Animals↗
PubMed1990

Fatigue testing.

Explore the source record for details and available documents.

Biomechanical Phenomena↗