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Biomedical subjects

A Miller

Publications and source records attributed to A Miller.

At least 631 records · Page 35Linked to original sources
PubMed1979

The limiting collagen microfibril. The minimum structure demonstrating native axial periodicity.

Collagen fibers were grown from solutions of acid-soluble or neutral salt-soluble collagen in 0.5 M acetic acid by rapid dialysis. The collagen was obtained under conditions where protease inhibitors were present at every stage of extraction and purification. Under the conditions used, length-wise but not lateral filament growth proceeded rapidly and gel-like networks were formed, Water readily exuded from the networks. The networks were stretched to fibrous form during drying. Small-angle X-ray diffraction showed the stretched fibrils to be highly ordered, showing up to 20 orders of the 670 A meridional periodicity. Intermediate- and wide-angle photographs show equatorial reflections at a spacing corresponding to approximately 12.5 A which is related to the intermolecular distance but none related to a microfibrillar packing at the 35-40 A level. Electron microscopy of the gel networks before stretching shows the presence of thin filaments with diameters predominantly in the 35-40 A range. No cross-striated fibrils are seen in electron micrographs of either stretched fibers or unstretched fibers. Thus, intermolecular packing in accord with the 670 A axial periodicity can take place within approximately 40 A diameter thin filaments. These correspond to the structures previously postulated to be collagen 'microfibrils'.

Animals↗
PubMed1979

Sickle cell anemia and trait in southern India: further studies.

Population surveys and family studies among 568 members of nine ethnic groups in southern India identified 15 homozygotes for sickle hemoglobin (HbS)who had mild clinical and hematological manifestations with high levels of fetal hemoglobin (mean=20%, range 8-36%) in a heterogeneous red cell distribution. In one family, the heterozygous mother had a hemoglobin pattern consistent with a form of the heterocellular hereditary persistence of fetal hemoglobin. Sickle cell trait was found in 153(27%) of those studied. Chromatographic quantitation of the hemoglobin fractions in these heterozygotes showed a trimodal distribution of the proportion of HB Sexplicable by a genetic model postulating the presence of genotypes with two (-alpha/-alpha), three (-alpha/alpha alpha) and four (alpha alpha/alpha alpha) active alpha-globin genes. Globin synthesis studies in four heterozygotes believed to have two active alpha-globin genes demonstrated an alpha/non-alpha total activity ratio (0.57) consistent with this model.

Anemia, Sickle Cell↗
PubMed1979

Covalent binding of carbaryl (1-naphthyl-N-methyl-carbamate) to rat liver microsomes in vitro.

Enzyme mediated binding of carbaryl (1-naphthyl-N-methylcarbamate) to rat hepatic microsomes occurred in vitro in the presence of reduced nicotinamide adenine dinucleotide phosphate (NADPH) and oxygen and was inhibited by nitrogen, carbon monoxide, reduced glutathione, cysteine, N-ethyl maleimide, and 2-diethylaminoethyl-2,2'-diphenylvalerate-HCl (SKF 525-A). Binding was markedly increased, 2- to 3-fold, by pretreatment of animals with phenobarbital or 3-methylcholanthrene and appeared to be dependent on the production of an active metabolite which was formed oxidatively in liver microsomes by cytochrome P-450 mixed-function oxidases. SDS-polyacrylamide disc gel electrophoresis of ether-extracted, solublized microsomes and the distribution of radioactivity after Pronase digestion, treatment with 1-fluoro-2,4-dinitrobenzene, and extraction with ethyl acetate and ether at pH 9 and 1 indicated that the radiolabeled products were covalently bound to amino acid residues of microsomal protein.

Animals↗
PubMed1979

The natural history and surgical significance of hyperlipemic abdominal crisis.

Although it is widely known that patients with severe hyperlipemia may have pancreatitis, it is not generally appreciated that such patients may have recurrent abdominal pain of variable character and intensity not due to pancreatitis. Review of 35 patients followed in our clinic for 1--11 years showed that 54% had recurrent abdominal pain, while only 29% had pancreatitis. Although mild pain occurred frequently with plasma triglycerides in the 2000--5000 mg/dl range, triglycerides over 6000 mg/dl were often associated with severe pain and physical findings which necessitated hospitalization, often led to the misdiagnosis of pancreatitis and other intra-abdominal catastrophes and resulted in multiple unnecessary diagnostic studies and operations. When recognized, the pain subsided within 48 hours upon cessation of oral intake and treatment with intravenous electrolyte solutions. Furthermore, effective treatment of the hyperlipemia prevented both the attacks of severe pain and the pancreatitis which otherwise occurred (or recurred) in a significant fraction of the patients. These data confirm the existence of hyperlipemic abdominal crisis as a distinct entity and testify to the importance of recognizing this syndrome in order to avoid the occurrence of acute pancreatitis and the performance of unnecessary and potentially harmful surgery.

Abdomen↗
PubMed1979

Pathogenesis of visna. IV. Spinal fluid studies.

Visna is a persistent retrovirus infection of sheep which produces a chronic progressive paralytic disease after an incubation period lasting from months to years. The cerebrospinal fluid (CSF) was repeatedly sampled in a group of Icelandic sheep which were infected intracerebrally and followed up to 42 months. Minimal levels of infectious virus were isolated from the cerebrospinal fluid (CSF) up to 4 months after infection after which CSF neutralizing antibodies appeared in many sheep. These antibodies varied in titer and in some animals exceeded serum antibody levels which were moderate to high. CSF antibody is apparently produced within the CNS by local proliferation of B cell clones, and is accompanied by the appearance of considerable numbers of plasma cells in the neural parenchyma. Some sheep raised serum antibody to a second serotype of visna virus and in a number of these animals heterotypic antibody was also found in the CSF. An increase in CSF leukocytes often occurs within 1 to 3 months following infection and may then persist or wane. A persistent high level of CSF cells is an indicator of progressive CNS disease and such animals are more likely to yield virus, have higher CSF antibody levels, more severe CNS lesions, and an enhanced risk of clinical illness (progressive paralysis). CSF cells are predominantly macrophages and lymphocytes, with a consistent minority of plasma cells.

Animals↗
PubMed1979

Recurrent atraumatic subungual splinter hemorrhages in healthy individuals.

Four individuals with severe, chronic, recurrent splinter hemorrhages are reported. The duration of splinter hemorrhages ranged between six and 30 years. The fresh lesions were associated with burning sharp pain and tenderness which lasted for a few days. Although commonly located in the distal one third of nails, they were often found in the middle and the proximal third as well. In-depth review of these individuals' history, physical examination, and laboratory values failed to reveal recurrent trauma, drug use, or any underlying systemic disease. Based on these findings we conclude that chronic subungual splinter hemorrhages are nonspecific findings and may be seen in both health and disease states.

Adult↗
PubMed1979

The structure of goat hemoglobins. V. A fourth beta chain variant (beta-D-Malta; 69 Asp is replaced by Gly) with decreased oxygen affinity and occurring at a high frequency in Malta.

During a survey of hemoglobin types in goats in the Republic of Malta a variant (Goat Hb D-Malta) was discovered which differs from normal goat Hb A by the substitution of an aspartyl residue in position beta 69 (E13) by a glycyl residue. The gene frequency of the beta D allele was 0.255; 29 homozygous Hb D goats were present among 327 animals sampled. Homozygous Hb D goats also produce Hb C, whose beta chains are the product of a non-allelic beta C structural gene. Goat Hb D-Malta has a distinctly decreased affinity for molecular oxygen.

Amino Acid Sequence↗
PubMed1979

Effect of sodium fluoride on cyclic AMP production in rat hepatocytes.

The effect of NaF on cAMP production was studied in hepatocytes isolated from fed and fasted rats. A four-six fold increase in hepatocyte cAMP production was observed in the presence of 10-20 mM NaF in cells isolated from either fed or fasted rats. The maximal stimulation of cAMP production was observed after a 10 min incubation in the presence of 1 mM theophylline. However, as little as 0.05-0.15 mM NaF induced a significant increase in cAMP production. It was also found that NaF would alter the production of glucose in isolated rat hepatocytes. When hepatocytes from fed rats were incubated with 0.05-5 mM NaF there was an increase in amount of glucose released from endogenous sources. Also NaF resulted in a decrease in lactate and pyruvate production. Similarly NaF stimulated glucose production in hepatocytes from fasted rats. The maximal stimulation was observed with about 0.15-0.25 mM NaF. At NaF concentrations greater than 1.5 mM a decrease in glucose production was observed. It is concluded that NaF increases the level of cAMP and alters glucose metabolism in intact hepatocytes.

Animals↗
PubMed1979

Delayed advent of stringent, non-H-2 genetic regulation of the antibody response to a protein antigen.

The role of non-H-2 gene(s) in the control of the antibody response to three lysozymes was investigated. Upon secondary challenge, A/J (H-2a) mice generated at least a 25-fold greater anti-lysozyme plaque-forming cell response than did B10.A (H-2a) mice. Nearly equal, strong peak primary responses, predominantly IgG in nature, were obtained from both A/J and B10.A mice after a single challenge with lysozyme in complete Freund's adjuvant. However, clear differences in responses are seen within 5 days after the peak primary plaque-forming response and by day 28 at the serum antibody level. B10.A mice never equal their primary responses, whereas A/J mice demonstrate positive immune memory. It appears that a non-H-2 gene(s) that regulates the overall antibody level to a protein antigen becomes manifest only after an initial antibody response.

Animals↗
PubMed1979

The drama of the gifted child and the psycho-analyst's narcissistic disturbance.

In order to develop a true self, the child needs, in the first weeks and months of his life, his mother's appropriate emotional response, mirroring and respect. These narcissistic aspects have to be distinguished from the drive wishes. Only the mother's appropriate responses make it possible for the child to experience his feelings as belonging to his own self. If the child does not get the right narcissistic response, he will continue to search for narcissistic supplies for the rest of his life. The most suitable objects for this will be his own children initially, who are completely at his disposal. Specially gifted children who are sensitive, alert and have many 'antennae', will quickly learn to adapt to the narcissistic needs of their parents. Their behaviour will then give the mother all the mirroring, consideration and admiration which she had missed as a child herself. The result will be that, in spite of excellent performance, the child's own true self cannot develop. All this leads to narcissistic vulnerability and to new attempts in the adult to find at last an available 'mother' in his own child, partner, or, if he has become a psycho-analyst, in his patient. In the transference this type of analysand first experiences narcissistic rage before deep mourning is possible. This process of mourning enables him finally to accept his own deprivation as a child, to give up the unconscious idealizations and with them the hope of finding such a 'mother'. This leads regularly to the liberation of the life forces and allows creativity to develop. Only after this has been achieved is the analysis of drive conflicts possible and becomes emotionally effective.

Child Development↗
PubMed1979

The response of the lower extremity to impact forces. II. Computerized mechanical impedance measurements.

The preferred method for the noninvasive assessment of the mechanical properties of the musculoskeletal system is the measurement of mechanical impedance by means of an instrumented impact hammer and accelerometer. When coupled to an interactive computer system, this is shown to be a powerful tool in the quantitation of mechanical parameters associated with various orthopaedic conditions. The technique of measurement and the interpretation of results is discussed with reference to a model based on elastic rebound.

Biomechanical Phenomena↗