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Biomedical subjects

D L Miller

Publications and source records attributed to D L Miller.

At least 505 records · Page 28Linked to original sources
PubMed1976

Effects of diabetes on intestinal magnesium absorption in the rat.

Control and streptozotocin-diabetic rats were studied at 5, 12, and 32 days after induction of diabetes. Magnesium absorption was measured by in situ perfusion of duodenum and ileum. At 5 days, duodenal mucosal growth is similar in controls and diabetics. At 12 days, mucosal growth is 50% greater in diabetics, and at 32 days, 100% greater. Ileal mucosal growth followed the same pattern but was half that of duodenum. Therefore, absorption data were expressed per centimeter segment length to define absorptive capacity of the segment and per gram dry weight of mucosa to define absorptive specific activity. Mean absorptive specific activity was lower in diabetics than controls at all time intervals. The difference was significant only for duodenum of diabetics at 32 days, when magnesium absorption declined to half that of controls. In contrast, absorptive capacity for both segments remained the same in both groups, attributable to the greater mucosal growth in diabetics. These findings for magnesium contrast with effects of diabetes on calcium transport: specific absorption and segment absorptive capacity are depressed in diabetics at both 5 and 11 days. Thus, although transport of magnesium and calcium usually tend to change in parallel in diabetes, transport of magnesium is depressed later and to a lesser degree than calcium, and segment transport capacity is maintained. The findings suggest differences in mechanism of regulation of magnesium and calcium transport.

Animals↗
PubMed1976

Effects of experimental diabetes on intestinal strontium absorption in the rat.

Control and streptozotocin diabetic rats were studied at 5 and 12 days after induction of diabetes. Strontium absorption was measured by in situ perfusion of duodenum and ileum. Duodenal absorptive capacity (absorption per unit length) and absorptive specific activity (absorption per gram of dry weight mucosa) were depressed. Depression was present both at 5 days, when mucosal growth is similar in controls and diabetics, and at 12 days, when mucosal growth is 50% greater in diabetics. Effects of diabetes on ileal absorption were minimal in comparison with effects on duodenum. This depression of duodenal strontium absorption in the diabetic rat is analogous to effects of diabetes on calcium absorption and may be mediated by abnormal vitamin D metabolism.

Animals↗
PubMed1975

Guanylate cyclase in Escherichia coli. Purification and properties.

Guanylate cyclase has been purified from extracts of Escherichia coli. After a 1000-fold purification, the enzyme contains only minor contaminants as judged by disc gel electrophoresis. The Km for GTP is approximately 7 times 10(-5) M and the optimal pH is 8.0. More activity is observed with Mn2+ than with Mg2+, and maximal activity is observed at 0.14 mM Mn2+ and 1.4 mM Mg2+. Based on its behavior on Sephadex G-100, the molecular weight of E. coli guanylate cyclase is about 30,000. Disc gel electrophoretic analysis indicates that the enzyme consists of a single polypeptide chain. Guanylate cyclase does not form 3':5'-AMP from ATP, and therefore, is distinct from adenylate cyclase.

Enzyme Activation↗
PubMed1975

Epidemic Venezuelan equine encephalitis in North America in 1971: vector studies.

A major epidemic of Venezuelan equine encephalitis occurred in south Texas in the summer of 1971. More than 1500 equines died of VEE in Texas, and 110 human cases with no deaths were reported. Vector studies in south Texas and northern Tamaulipas revealed that the overall mosquito infection rates during the peak of the epidemic were about 1:100, one of the highest rates observed for a major epidemic. Mosquito infection rates of this magnitude could easily explain the intensity of VEE outbreaks in both equines and man. A total of 943 VEE virus isolations were made from mosquitoes. Eight of the 12 mosquito species found infected were implicated in the epidemic cycle of VEE for the first time. Sufficient laboratory and field evidence is available to prove that Psorophora confinnis was one of the primary vectors of VEE. The lack of laboratory evidence necessitates the use of the term "probable" primary vectors for other species apparently equally as involved on the basis of field infections; these include Aedes sollicitans, Aedes thelcter and Psorophora discolor. Eight other species from which less than 10 VEE virus isolations were made were considered auxiliary vectors. Mosquitoes of some species were tested individually; such tests showed 2-4% of the probable primary vectors to be infected. The first isolation of VEE virus of the epidemic was made from P. confinnis on June 28, 1971. Highest mosquito infection rates occurred during the week of July 5. Mosquito infection rates declined precipitously in the last 3 weeks of July 1971, signaling the end of the epidemic in the study area. One explanation for the decline was that equines, the principal epidemic hosts, were eliminated as a source of virus by death or by acquisition of natural or induced immunity. Mosquito control appeared to be effective in reducing the infected mosquito population while the immunization of equines with TC 83 VEE vaccine was accomplished. Quarantines appeared to be effective in restricting the VEE virus activity to south Texas. Undoubtedly all of the control measures contributed to stopping the epidemic. Continued VEE surveillance by various government and other agencies failed to reveal any further epidemic VEE activity in the US in 1972. Other arboviruses isolated during the VEE studies in south Texas included St. Louis encephalitis virus, and San Angelo subtype of the California Group. A virus of the Bunyamwera Group was also isolated from Palo Blanco, Tamaulipas.

Animals↗
PubMed1975

Epidemic Venezuelan equine encephalitis in North America in 1971: vertebrate field studies.

Epidemic Venezuelan equine encephalitis in North America in 1971: vertebrate field studies. Am J Epidemiol 101:36-50, 1975.-In June 1971, epidemic Venezuelan equine encephalitis (VEE) invaded the lower Rio Grande Valley in south Texas. The Boca Chica area of Cameron County was selected as a study site to investigate vertebrate involvement in the natural cycle of epidemic VEE on the basis of considerable evidence of VEE virus activity there in equines, humans, and mosquito vectors. Only one VEE virus isolation was made from 4739 wild and domestic non-equine vertebrates, although numerous equine and human VEE virus isolations were made in concurrent studies. Serologic studies indicated that VEE virus activity was far greater in large domestic animals than in wild birds, wild mammals, or reptiles. Apparently epidemic VEE virus failed to establish itself in a wild vertebrate cycle in south Texas, since VEE antibody was found only in rabbits in 1972. Eventual cessation of VEE transmission in south Texas has been attributed 1) to the elimination of equines as a source of VEE virus by death, naturally acquired antibodies, or vaccination, 2) to quarantines, 3) to mosquito control, and 4) to the failure of epidemic VEE virus to become established in the wild vertebrate population. Equines emerge as the most important vertebrate host in the amplification and spread of virus during an epidemic of VEE.

Animals↗
PubMed1975

Ethanol fermentation and potential.

Ethyl alcohol is one of the United States and world's major chemicals. Beverage alcohol in the United States must be prepared from cereal grains or other natural products. The U.S. industrial alcohol market has remained relatively stable for several years at approximately 300 million gallons annually. Most of this has been produced synthetically from petroleum raw material (gas and oil). These raw materials are experiencing major price increases and are in short supply. The production of ethyl alcohol from cereal grains and cellulosic raw materials by fermentation is technically feasible and has been proven. Alcohol produced from all such materials is equal to synthetic alcohol in quality and performance. Competitive economics have controlled the basic raw materials used. The major potential new ethyl alcohol market is as a component of automobile fuels. A 10% alcohol-gasoline blend in the United States would annually require over 10 billion gallons of anhydrous alcohol. Use of alcohol for this purpose is technically feasible. However, alcohol has not been economically competitive to date.

Cellulose↗