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Biomedical subjects

M Miller

Publications and source records attributed to M Miller.

At least 793 records · Page 44Linked to original sources
PubMed1979

Effect of ionophores on carrier-mediated electron translocation in ferricyanide-containing liposomes.

Ferricyanide-containing liposomes were used as a system to compare the electron- and proton-translocating properties of six redox reagents commonly used as electron donors for biochemical systems. The effects of different ionophore combinations on the ferricyanide-reduction rate were generally consistent with the expected proton- and electron-translocating properties of the mediators. The transmembrane pH gradient produced by hydrogen carriers was demonstrated. Nigericin or valinomycin plus carbonyl cyanide p-trifluoromethoxyphenylhydrazone are capable of collapsing this gradient and of stimulating ferricyanide reduction mediated by this type of carrier. No pH gradient is produced with the electron carrier 1,1'-dibutylferrocene. In the presence of tetraphenylboron anion, which is needed for this carrier to act as an efficient mediator, addition of valinomycin alone is sufficient to obtain full stimulation of ferricyanide reduction. NNN'N'-Tetramethyl-p-phenylenediamine does not behave as a simple electron carrier. During NNN'N'-tetramethyl-p-phenylenediamine-mediated ferricyanide reduction protons are translocated across the membrane and accumulated in the vesicles. This is not due to the presence of demethylated impurities in the NNN'N'-tetramethyl-p-phenylenediamine sample, but may be the result of an accumulation of oxidation products other than the Wurster's Blue radical. These results suggest a reconsideration of studies on protonmotive forces across membranes where NNN'N'-tetramethyl-p-phenylenediamine is used as a mediator.

Electron Transport↗
PubMed1979

Familial, balanced insertional translocation of chromosome 7 leading to offspring with deletion and duplication of the inserted segment, 7p15 leads to 7p21.

We report an uncle and niece with duplication and deletion, respectively, of segment 7p15 leads to 7p21 originating from a balanced, intrachromosomal insertion in their mothers. The proposita had prenatal and postnatal growth deficiency, retarded psychomotor development, microcephaly, wide cranial sutures, ocular hypertelorism, small palpebral fissures, apparently low-set and malformed ears, cleft palate, congenital heart defect, hypoplasia of the distal phalanx of first fingers, rocker-bottom feet, persistent cloaca, and imperforate anus. She died at three months. Her maternal uncle has duplication of this segment and is alive at 32 years. He has severe mental deficiency, but normal growth; communicating hydrocephalus was diagnosed at three months.

Abnormalities, Multiple↗
PubMed1979

Fasting and two-hour post-load glucose levels for the diagnosis of diabetes. The relationship between glucose levels and complications of diabetes in the Pima Indians.

The frequency distributions of both the fasting and two-hour post-load plasma glucose levels were bimodal in the Pima Indian population aged 25 years and over. The hyperglycaemic component of this distribution represents those with diabetes mellitus, as some 30 percent of this group had evidence of the specific vascular complications of the disease, whereas these abnormalities were virtually absent in those with lower glucose levels. The bimodal characteristics of the frequency distributions were utilized to define optimal criteria to separate those with and without diabetes. The sensitivity and specificity of these criteria for fasting and two-hour glucose levels were compared and were found to be similar. The fasting glucose determination, however, was more reproducible and stable, as well as being easier to obtain, indicating that it is the better measurement for diagnostic purposes. The optimal level for diagnosis of 7.5 mmol/l (136 mg/dl) for the fasting glucose and the equivalent two-hour value of 14 mmol/l (250 mg/dl), were higher than many previously recommended diagnostic levels. Nevertheless, there was no evidence that subjects with lower levels were at appreciable risk of developing the specific complications of diabetes. Subjects with impaired glucose tolerance (IGT), but without fasting hyperglycaemia, should not be diagnosed as having diabetes mellitus.

Adolescent↗
PubMed1979

Recent status of detection, treatment, and control of hypertension in the community.

The Hypertension Detection and Follow-up Program (HDFP), a national collaborative study, screened approximately 159,000 people for high blood pressure in 14 communities between 1973 and 1974. Results show that detection, treatment, and control of high blood pressure has improved considerably since the 1960s. Whereas in the past about half of all hypertensives knew they had high blood pressure, half of those detected were under treatment, and half of those under treatment had their high blood pressure under control, the corresponding percentages in the 14 HDFP communities a decade later indicate that 75% of hypertensives were detected, 72% of those were under treatment, and 70% of those under treatment had a diastolic blood pressure under 95 mm Hg. While the differences in prevalence of hypertension are between races rather than sexes (with black individuals in some age groups being about twice as likely as white individuals to have hypertension), the differences in detection and treatment rate are largely between sexes and not between races. Women are considerable more likely to be aware of their hypertension, to be under treatment for it, and to have their high blood pressure under control. Rates of control vary considerably among age-sex-race subgroups, from only 8% of white male hypertensives aged 30-39 to 67% of white female hypertensives aged 60--69. It appears that although efforts to combat this disease over the past decade have probably made considerable progress in improving the recognition and treatment of high blood pressure, there remain a large number of undetected, untreated, and uncontrolled hypertensives.

Adult↗
PubMed1979

Developmental protein malnutrition: influences on the central nervous system of the rat.

Our group has been carrying out interdisciplinary studies on the effects of prenatal and postnatal protein malnutrition on the developing rat brain. Anatomical, physiological, biochemical and behavioral approaches using the same animal model have revealed that protein malnutrition affects the brain at various levels, i.e., (1) anatomical, as revealed by Golgi findings of deranged dendritic trees on analysis of cortical and subcortical areas; (2) physiological, as revealed by delayed sleep pattern maturation, disturbances in seizure thresholds, slowing of sensory cortico-cortical and thalamocortical evoked potentials, and changed power in hippocampal theta activity; (3) biochemical, as revealed by marked increases in biogenic amines dating from birth, as well as modifications in tryptophan metabolism; and (4) behavioral, as revealed by various changes in responses to different kinds of aversive stimulation. Reversal studies have revealed that many changes are permanent and not amenable to nutritional rehabilitation even at birth, which is before the brain growth spurt in the rat. Our paradigm closely mimicks the human condition of low level, chronic protein undernutrition and thus reveals the underlying disturbances due to malnutrition. The dietary reversal studies are attempts at pin-pointing critical brain growth periods, beyond which recovery of functions is not possible.

Animals↗
PubMed1979

Postaxial acrofacial dysostosis syndrome.

Three patients with a postaxial acrofacial syndrome are presented; the features of these and three other previously described examples are set forth. The facies can be strikingly similar to that of the Treacher Collins syndrome. The limb deficiencies are postaxial, with absence or incomplete development of the fifth digital rays in both the upper and lower limbs. Accessory nipples have been found in most of the patients. The nature of the limb deficiencies and the accessory nipples help to distinguish this condition from Nager AFD. All of the children have normal intelligence and development; most show normal growth. All of the six cases have occurred sporadically.

Abnormalities, Multiple↗
PubMed1979

Partitioning of C-photosynthate, and long distance translocation of amino acids in preflowering and flowering, nodulated and nonnodulated soybeans.

The influence of stage of development (preflowering versus flowering) in nodulated and nonnodulated soybeans (Glycine max [L.] Merr. cv. Wells) on partitioning of (14)C into assimilates following exposure of a soybean leaf to (14)CO(2) by both steady-state and pulse-labeling techniques was studied. Blades on the second fully expanded leaf from the stem apex were exposed to (14)CO(2). Radioactive assimilates were extracted from source leaf blades, petioles, and stems (both the path up and path down from source leaf), were separated into neutral (sugars), basic (amino acids), and acidic (organic acids, sugar phosphates) fractions by ion exchange chromatography. The basic fraction was further resolved using thin layer chromatography and the percentage of radioactivity recovered in each amino acid was determined.The distribution of radioactivity in the neutral, basic, and acidic fractions of the source leaf blades was significantly different from that of the transport path (petiole and stems). About 70% of the radioactivity in source leaf blades was recovered in the neutral fraction, whereas about 90% of the recovered radioactivity in the path was in the neutral fraction. (14)C-Aminoacids constituted 8 to 17% and 2 to 7% of the recovered radioactivity in source leaves and paths, respectively. Recovered (14)C in organic acids ranged from 13 to 20% and 2 to 7% in source leaves and paths, respectively. Partitioning of (14)C-assimilates among the neutral, basic, and acidic fractions was not affected by the presence of nodules or flowers. However, when steady-state labeling was compared to pulse labeling, a significantly lower percentage of (14)C was recovered in the neutral fraction with a concomitant increase in the basic fraction. Asparagine-arginine, serine, glutamate, gamma-aminobutyrate-alanine, and aspartate accounted for 69 to 85% of the recovered radioactivity in the basic fraction from the various treatments. [(14)C]Serine was significantly higher in pulse-labeling experiments, whereas glutamtate and proline were higher with steady-state labeling. [(14)C]Serine was significantly higher in nonnodulated plants than in nodulated plants, whereas gamma-aminobutyrate-alanine was significantly higher in preflowering plants as compared to flowering plants.

Journal Article↗
PubMed1979

High prevalence of diabetes in young Pima Indians: evidence of phenotypic variation in a genetically isolated population.

Medical records of the Pima Indian population aged 0--24 yr were reviewed for a diagnosis of diabetes before initiation of glucose tolerance testing. None of 1556 subjects below age 15, but 6 of 657 aged 15--24, had a previous diagnosis. Of the six known diabetics, five had been treated with insulin and four had had ketoacidosis. Subsequently, plasma glucose levels were determined after a 75-g oral carbohydrate load in 1712 subjects aged 5--24 yr, which is about 78% of the eligible population. Previously diagnosed diabetes and asymptomatic hyperglycemia were more frequent in subjects 15--24 yr old than were reported in other populations. Glucose intolerance in young Pimas was associated with obesity. In Pima offspring, the presence of diabetes in both parents was related to glucose tolerance in those above but not below the age of 15 yr. Both asymptomatic hyperglycemia and insulin-requiring diabetes occurred frequently in young Pimas, suggesting that these syndromes represent the clinical spectrum of a single disease in the Pima Indian.

Adolescent↗
PubMed1979

Bimodality of glycosylated hemoglobin distribution in Pima Indians: relationship to fasting hyperglycemia.

Glycosylated hemoglobin (HbA1) concentrations were determined in 300 Pima Indians aged 15 yr and older. Frequency distributions of HbA1 were unimodal in the 15--24-yr-old age group, but were bimodal in those aged 25 yr and over. The bimodality indicated that the subpopulation with diabetes could be identified by the presence of elevated HbA1 levels. This group was comprised primarily of subjects who also had fasting plasma glucose levels of less than or equal to 140 mg/dl, but subjects with impaired glucose tolerance without fasting hyperglycemia had HbA1 levels that were not significantly higher than those with normal glucose tolerance. The prevalence of diabetic retinopathy was much higher in the subgroup with elevated HbA1 levels and increased with increasing HbA1 level. HbA1 levels and triglyceride concentrations showed only a modest association. HbA1 determinations provided no advantage over fasting or post challenge glucose levels in the diagnosis of diabetes.

Adolescent↗
PubMed1979

The psychiatrist's family--a comparative study.

The results of a questionnaire survey of the partners of psychiatrists and general practitioners are presented. The questionnaire was designed to elicit feelings about the respective professions. Methodological issues are discussed, and the wisdom of comparing different medical groups is questioned. Although significantly fewer psychiatrists' partners initially had positive feelings towards their spouse's career, the majority of both groups reported currently positive feelings. Only a minority, and in equal proportions in the two groups, reported that their spouse's profession had interfered with their relationships with friends or had influenced their marital relationship. A significantly greater number of general practitioners' partners reported that their spouse's profession was more stressful than that of other professionals. The results also indicated that a significantly greater number of psychiatrists than general practitioners as perceived by their partners as using psychiatric interpretation and jargon in the family setting. Furthermore, the comments provided, although representative of only a minority of respondents, demonstrated that this could provide a unique stress for the families of some psychiatrists.

Adult↗