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Biomedical subjects

M B Jones

Publications and source records attributed to M B Jones.

At least 73 records · Page 4Linked to original sources
PubMed1992

Effects of olestra, a noncaloric fat substitute, on daily energy and fat intakes in lean men.

Nutrient and energy intakes, hunger, and fullness were examined after the replacement of 36, 20, or 0 g fat in breakfast with olestra, a noncaloric fat substitute. Twenty-four lean, nondieting men (aged 21-30 y) participated in a placebo-controlled, three-condition crossover design. Self-selected, ad libitum intakes at lunch and dinner were monitored in the laboratory. Evening snacks and breakfast the next day were assessed through food diaries. Visual-analog-scale ratings including hunger and fullness were collected throughout the test days. Single-meal olestra substitution produced a significant dose-related reduction in the amount and percentage of energy from fat consumed daily with a reciprocal increase in carbohydrate intake. Daily energy intakes were not significantly different nor did ratings of hunger and fullness vary systematically between conditions. Consumption of olestra can reduce fat intake and increase carbohydrate intake without affecting total daily energy intake or usual patterns of hunger and fullness.

Adult↗
PubMed1992

Comparison of ketorolac and morphine as adjuvants during pediatric surgery.

The intraoperative use of opioid analgesics decreases the volatile anesthetic requirement and provides for pain relief in the early postoperative period. In a randomized double-blind, placebo-controlled study involving 95 ASA physical status 1 or 2 children (ages 5-15 yr) undergoing general anesthesia for elective operations, we compared postoperative analgesia following the intraoperative intravenous (iv) administration of ketorolac, a nonsteroidal antiinflammatory drug or morphine, an opioid analgesic. After induction of general anesthesia and before the start of the surgical procedure, children received equal volumes of saline, morphine (0.1 mg.kg-1, iv) or ketorolac (0.9 mg.kg-1, iv). Postoperative pain was evaluated by the child using a 10-cm linear visual analog scale (VAS) and by a blinded observer using both a VAS and an objective pain scale (OPS) in the postanesthesia care unit (PACU). There were no statistically significant differences in the VAS and OPS scores in the PACU or in the postoperative analgesic requirements in children receiving morphine or ketorolac. The placebo group had a significantly higher VAS and OPS score and required earlier and more frequent analgesic therapy in the PACU compared to the two analgesic groups. Patients receiving ketorolac had less postoperative emesis than those receiving morphine. We conclude that ketorolac (0.9 mg.kg-1) is an effective alternative to morphine (0.1 mg.kg-1) as an iv adjuvant during general anesthesia, and in the dose used in this study, is associated with less postoperative nausea and vomiting in children.

Adjuvants, Anesthesia↗
PubMed1992

Specificity of effect in psychiatric research.

In the last ten years the genes responsible for Huntington's disease and several other neurological disorders have been localized to specific chromosomes. Huntington's disease is now known to be caused by a gene on the short arm of chromosome 4. While these advances are welcome, they also pose a problem. All studies to date have been passive observational studies; none has been experimental. Arguably the most successful and significant attributions of cause in neurological history have been achieved by non experimental methods. This realization is somewhat disconcerting, considering that virtually all textbooks in epidemiology insist that true experiments (randomized trials) are the prime means of establishing cause. One cannot help but ask how these unauthorized successes were achieved. What are the principles of investigation that made them possible? In this paper we argue that the recent advances in neurological genetics, along with much else in human genetics, depend heavily on "specificity of effect." Just what this principle is and how it allows successful attribution of cause is explained. Various applications elsewhere in the medical and behavioural sciences and in psychiatry are discussed.

Chromosomes, Human, Pair 4↗
PubMed1991

Vitamin K status of free-living subjects consuming olestra.

The potential for 20 g olestra/d to affect vitamin K status was assessed in a 6-wk study involving 202 free-living subjects. Functional prothrombin [Simplastin (S)-Ecarin (E) assay] concentrations and classical clotting times were unaffected by olestra. Initial S:E values were 0.80 and 0.79 for the olestra and placebo groups, respectively, compared with a value of 0.92 for normal reference plasma. At week 6 the value was 0.81 for both groups. Mean phylloquinone serum concentrations, expressed as differences from baseline, were not significantly different between groups. Weekly food diaries indicated that the average phylloquinone intake of the subjects was low, approximately 60 micrograms/d. Sensitive measures of vitamin K status were unaffected in a population where any significant decrease in phylloquinone bioavailability should have been reflected in those measures, indicating that 20 g olestra/d in the diet did not affect vitamin K status.

Adult↗
PubMed1991

Serum 25-hydroxyvitamin D concentrations of free-living subjects consuming olestra.

The effect of olestra on vitamin D status was assessed in a 6-wk, double-blind, placebo-controlled study involving 202 free-living adults. Subjects consumed a total of 20 g/d of olestra or triglycerides in cookies eaten at each meal. A 20-micrograms ergocalciferol capsule was taken with each morning meal. Serum 25-hydroxyergocalciferol (25-OHD2) concentrations rose from approximately 5.7 to 39.0 and 31.7 nmol/L in the placebo and olestra groups, respectively, at week 6. At week 6, 25-OHD2 contributed 46-54% to total serum 25-OHD concentration compared with 11% at baseline. The 19% decrease in serum 25-OHD2 concentrations produced by olestra in this study is equivalent to a decrease of approximately 1.2 nmol/L under nonsupplemented dietary conditions. Ingesting 20 g olestra/d in the diet is thus not expected to affect vitamin D nutritional status.

25-Hydroxyvitamin D 2↗
PubMed1991

IQ and the genetics of autism.

While there seems to be general agreement that genetic factors play some role in the etiology of autism, many important questions remain unresolved. The purpose of this paper is to review five issues with respect to the association between low IQ and autism from a familial-genetic viewpoint: (1) does IQ estimate the severity of the autistic genotype?; (2) what is the relationship between probands' and sibs' IQs?; (3) what is the relationship between parents' and probands' IQs?; (4) why do females with autism have lower IQs than males with the disorder?; and (5) does IQ vary with the cause of autism? With respect to each issue, possible resolutions are outlined, as are the implications for understanding the genetic mode of transmission. The review concludes with a possible model for the genetic etiology of autism.

Autistic Disorder↗
PubMed1990

A newly identified iron binding protein in duodenal mucosa of rats. Purification and characterization of mobilferrin.

An iron binding protein with an approximate molecular mass of 56,000 daltons was purified to homogeneity from homogenates of rat duodenal mucosa. The protein was biochemically and immunologically distinct from transferrin and ferritin and competitively bound cobalt, copper, zinc, and lead. Each molecule bound one molecule of iron with a Kd of 9 X 10(-5). Dissociation of iron and the protein was accelerated at acid pH. Using an immunogold method, the protein was identified in the apical cytoplasm of proximal small intestinal cells and was not observed elsewhere in the intestinal mucosa and in other body organs. It was named mobilferrin from its city of origin and to differentiate it from other previously identified iron binding proteins.

Amino Acids↗
PubMed1990

The effect of olestra on systemic levels of oral contraceptives.

The effect of olestra, a nonabsorbable, noncaloric fat replacement, on the absorption and efficacy of a highly lipophilic oral contraceptive was investigated in a double-blind, placebo-controlled crossover study with 28 women. Subjects consumed 18 gm/day olestra for 28 days while taking an oral contraceptive containing 300 micrograms of norgestrel and 30 micrograms ethinyl estradiol (Lo/Ovral-28). Blood taken on days 12 to 14 of the treatment cycles was analyzed for ethinyl estradiol and norgestrel. There was no statistically significant difference in time to attain maximum concentration, maximum concentration, or area under the concentration-time curve between the olestra and placebo treatments for either drug component. Measurements of serum progesterone indicated that olestra ingestion did not reduce efficacy as indicated by ovulation. The data show that ingestion of 18 gm/day olestra did not affect the absorption or efficacy of the highly lipophilic oral contraceptive.

Adult↗
PubMed1990

Lung fibroblasts from animals breathing 100% oxygen produce growth factors for alveolar type II cells.

Type II cells were isolated from rats with a purity of 80-95% with less than 4% macrophages. These cells, after plating for approximately 16 h, were cultured with 50% RPMI 1640 and 50% (vol/vol) conditioned medium obtained from confluent hamster lung fibroblasts, together with 0.1% fetal calf serum (FCS). Conditioned media were obtained from either fibroblasts derived from normal hamsters breathing room air [normoxic-conditioned medium (NCM)] or from hamsters exposed for 4 days to 100% O2 [hyperoxic-conditioned medium (HCM)]. Controls consisted of 100% minimal essential medium (MEM) containing 0.1% FCS. Over a 96-h culture period, NCM stabilized cell populations but was unable to induce proliferation. In contrast, at low cell densities, HCM could cause a two- to threefold increase in type II cell number within 24-48 h after introduction. This effect could not be demonstrated at high cell densities. When tested with FCS concentrations ranging from 0 to 10%, maximum effects were obtained using 0.1-0.2% FCS. We conclude that lung fibroblasts from oxidant-injured hamsters produce growth factors that can stimulate at least one mitotic division in cultured type II cells, which are plated at low density. These factors are absent, or present in much lower concentration, in lung fibroblasts from normal animals.

Animals↗
PubMed1990

Wound repair and the potential use of growth factors.

Failure of wounds to heal increases the physical and financial burden of hospitalization and increases the work load for health care professionals. Although careful attention to nutrition (including adequate replacement of vitamins and trace mineral elements), tissue perfusion and oxygenation, and wound dressing and sanitation promote more rapid and complete healing, some wounds respond only slowly or not at all to these conventional treatment modalities. A group of polypeptide growth factors, including epidermal growth factor, platelet-derived growth factor, transforming growth factor beta, and basic fibroblast growth factor, have been found to promote or hasten healing in animal models. This technology is now moving into the clinical arena where its potential for human healing must be evaluated.

Animals↗
PubMed1989

Reduction of antisocial behavior in poor children by nonschool skill-development.

PALS (for "participate and learn skills") was a nonschool skill-development program offered to all children 5-15 years of age living in a publicly supported housing complex in Ottawa, Ontario. While participation was excellent, none but marginal and possibly nonexistent spillover effects on school performance or behavior in the home were observed. However, clear and statistically significant changes occurred on unobtrusive measures of antisocial behavior outside home and school. A cost-benefit analysis indicated that potential savings, primarily in reduced vandalism but also in reduced police and fire costs, greatly exceeded the cost of mounting the program.

Achievement↗
PubMed1989

Regulation of lung cell proliferation by polypeptide growth factors.

In the last 10 years there has been an increased appreciation of the changes in lung cell populations that occur in association with the acute respiratory failure often induced by traumatic injury. Early events result in an accumulation in the lung of platelets, neutrophils, monocytes, and macrophages, a release of substances having potent cardiopulmonary and metabolic effects, and an ensuing edema and transudation of materials from the interstitium and capillaries into the alveoli. Further progression of the injury results in significant decreases in the number of endothelial and type I epithelial cells and a subsequent hyperplasia of fibroblasts and type II-like epithelial cells. Major sequelae of the latter stage of the disease are interstitial and interalveolar fibrosis, probably resulting from the increased number of fibroblasts present. The activity and composition of pulmonary surfactant are often perturbed. This review will discuss mechanisms that may be involved in these processes, with major emphasis on cell-cell interactions mediated through polypeptide growth factors. We describe the properties of certain growth factors commonly associated with inflammatory and wound healing reactions, discuss their cellular origins, and speculate on their possible roles in mediating the structural and physiological responses seen in the lung during acute respiratory failure. The majority of work done with lung cells has concentrated on interactions between macrophages and fibroblasts, and it is evident that macrophages are capable of producing mitogens affecting the proliferation of fibroblasts. However, from the results of studies that are less developed, it is possible that epithelial cells and immunologically stimulated cells could also be involved in these actions. We conclude that the homeostasis of lung cell populations may be influenced by both growth-stimulating and growth-inhibiting substances and potentially could involve interactions through growth factors of fibroblasts, macrophages, lymphocytes, alveolar epithelial cells, endothelial cells, and platelets. At this time the information on these purported interactions is quite limited and there are far more questions than answers.

Animals↗
PubMed1989

The UCLA-University of Utah epidemiologic survey of autism: recurrence risk estimates and genetic counseling.

The authors recently reported, in this journal, an epidemiologic survey of autism in Utah. Twenty (9.7%) of the 207 families ascertained had more than one autistic child. Analyses of these data revealed that autism is 215 times more frequent among the siblings of autistic patients than in the general population. The overall recurrence risk estimate (the chance that each sibling born after an autistic child will develop autism) is 8.6%. If the first autistic child is a male the recurrence risk estimate is 7%, and if a female 14.5%. These new recurrence risk estimates should be made available to all individuals who have autistic children and are interested in family planning.

Autistic Disorder↗
PubMed1989

Factor analysis and predictive validity of microcomputer-based tests.

11 tests were selected from two microcomputer-based performance test batteries because previously these tests exhibited rapid stability (less than 10 min, of practice) and high retest reliability efficiencies (r greater than 0.707 for each 3 min. of testing). The battery was administered three times to each of 108 college students (48 men and 60 women) and a factor analysis was performed. Two of the three identified factors appear to be related to information processing ("encoding" and "throughput/decoding"), and the third named an "output/speed" factor. The spatial, memory, and verbal tests loaded on the "encoding" factor and included Grammatical Reasoning, Pattern Comparison, Continuous Recall, and Matrix Rotation. The "throughput/decoding" tests included perceptual/numerical tests like Math Processing, Code Substitution, and Pattern Comparison. The output speed factor was identified by Tapping and Reaction Time tests. The Wonderlic Personnel Test was group administered before the first and after the last administration of the performance tests. The multiple Rs in the total sample between combined Wonderlic as a criterion and less than 5 min. of microcomputer testing on Grammatical Reasoning and Math Processing as predictors ranged between 0.41 and 0.52 on the three test administrations. Based on these results, the authors recommend a core battery which, if time permits, would consist of two tests from each factor. Such a battery is now known to permit stable, reliable, and efficient assessment.

Adult↗
PubMed1988

Stoppage rules and genetic studies of autism.

Parents may respond in various ways to the birth of a seriously affected child. They may, for example, decide not to have any more children or to have one more child and then stop. These various responses are called "stoppage rules" in the genetic literature. Where stoppage rules are operative, the order in which affected and nonaffected children are born is disturbed in definite ways. The present paper shows that stoppage rules are at work in a recently reported data set consisting of 46 multiplex families of childhood autism and, as a consequence, that the segregation ratio was underestimated in the original report. The implications of these results for genetic studies of autism are then discussed.

Autistic Disorder↗