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Biomedical subjects

M Miller

Publications and source records attributed to M Miller.

At least 775 records · Page 43Linked to original sources
PubMed1980

Successful treatment protocol for canine fang injuries.

The most common bite injury in the United States is that of the dog and is associated with serious social and economic problems. Our series of 61 dog bite patients shows a majority of them to be in children and of the face and neck. Our treatment protocol centers on copious saline pressure irrigation, meticulous wound and wound edge debridement, repeated copious saline pressure irrigation, adequate antibiotic treatment, and close postoperative monitoring. Two hundred fifteen dog bite wounds in 61 patients were closed with this regimen with only a single wound infection. This is a wound infection rate of 0.47% and a patient infection rate of 1.6%.

Adolescent↗
PubMed1980

Improvement by isosorbide dinitrate of exercise-induced regional myocardial dysfunction.

Sonomicrometry was used in 10 conscious dogs to measure regional segment length and dynamic wall thickness by telemetry in a zone supplied by the left circumflex coronary artery after implantation of an ameroid constrictor. When coronary obstruction was nearly complete and collaterals had developed (24-42 days), control exercise and exercise runs after oral isosorbide dinitrate were carried out. During control runs, significant increases occurred in hemodynamic parameters, and percent shortening in normal segments increased (P < 0.01). During the repeat runs after isosorbide dinitrate, there were smaller increases in left ventricular systolic and end-diastolic pressures and significantly reduced end-diastolic dimensions. In addition, percent wall thickening and percent segment shortening in the ischemic zone did not deteriorate significantly during exercise. In this animal model, which appears to mimic chronic single-vessel coronary heart disease, isosorbide dinitrate can prevent exercise-induced deterioration of regional myocardial function.

Animals↗
PubMed1980

Extrageniculostriate vision in the monkey. VII. Contrast sensitivity functions.

1. Psychophysical and electrophysiological experiments have indicated the importance of spatial frequency components and their respective contrasts and orientations for the recognition of patterns. It is in the striate cortex where these types of information first converge, a fact that lends support to the accepted crucial role of this structure in pattern discrimination. 2. Monkeys with total bilateral ablation of the striate cortex, however, retain a residual capacity for pattern discrimination and also can differentiate between a vertical and an oblique luminous bar. The present study explores their capacity for spatial frequency detection both as a function of contrast and, by extrapolation, at maximum contrast (visual acuity measure). 3. Monkeys were presented with a forced choice between a homogeneous target and a vertically oriented sinusoidal grating in a pulling-in apparatus. Stimuli were produced by the transillumination of transparencies at spatial frequencies of 0.5, 1.0, 2.0, 4.0, 8.0, 16, and 32 cycles/deg, in 0.1-log unit steps of contrast from 0.79 to 0.006. The stimuli subtended 8 degrees of visual angle and were matched for mean luminance at 20 cd/m2. After mastering the discrimination of one spatial frequency at the highest contrast, contrast thresholds were first estimated by a staircase technique, and then determined by the method of constant stimuli. The procedure was repeated for each spatial frequency before and after histologically verified total bilateral removal of striate cortex and partial damage to circumstriate cortices. 4. Discrimination at all spatial frequencies was mastered by all normal monkeys. Postoperatively, they could solve only problems with frequencies between 0.5 and 4.0 cycles/deg. 5. Contrast sensitivity (threshold-1) functions for normal and destriated monkeys have the characteristic inverted J shape. The high- and low-frequency limbs are related exponentially to spatial frequency, and the peak of the curve is about 2.0 cycles/deg. The dimensions of the functions, however, change significantly following the ablation. Sensitivity is depressed at all spatial frequencies. The mean "visuogram" indicates a 26-dB flat loss. 6. The mean high-frequency cutoff point is 43 cycle/deg preoperatively and 12 cycles/deg postoperatively, equivalent to 0.7' and 2.5' of arc, respectively. The latter value is not worse than 20/80 on the Snellen chart. 7. The variability of the response at each spatial frequency in the staircase method and the slope of the psychometric function derived from the method of constant stimuli provide a measure of "instability" and "precision," respectively, which are inversely related. Preoperatively, precision is significantly greater at high than at low spatial frequencies. Postoperatively, it is similar at all frequencies, and the values are lower than those determined preoperatively. 8. The results demonstrate that destriated monkeys can detect gratings, although to a lesser degree than normal animals...

Animals↗
PubMed1980

Role of endogenous opioids in neurohypophysial function of man.

Studies were carried out in normal human subjects to determine the effect of two narcotic antagonists, oxilorphan and butorphanol, on antidiuretic hormone (ADH) release. Oxilorphan given to eight subjects on ad libitum fluid intake resulted in a transient but significant increase in 24-h free water clearance and a decrease in urine osmolality. These changes were not accompanied by an increase in creatinine or solute excretion, and urinary ADH levels did not rise even though plasma osmolality rose significantly from 289.4 +/- 0.9 to 292.9 +/- 0.8 mosmol/kg. Treatment with oxilorphan did not interfere with the response to ADH infusion in water-loaded subjects. Both oxilorphan and butorphanol significantly elevated the plasma osmolality at which ADH release became evident after the infusion of hypertonic saline in water-loaded subjects. Oxilorphan suppressed urinary ADH excretion at the time of the osmotic threshold for ADH release in spite of the greater plasma osmolality. The data indicate that the narcotic antagonists are capable of inhibiting ADH release in man during ad libitum fluid intake and in response to an osmotic stimulus by elevating the osmotic threshold for ADH release. It is concluded that narcotic antagonist inhibition of endogenous opioid action provides further evidence supporting a role for the brain opiates in the normal regulation of neurohypophysial hormone release in man.

Adult↗
PubMed1980

"Nautral" canine model of infantile hydrocephalus.

A review of the current knowledge about a variety of aspects of infantile hydrocephalus suggests that one cause of this problem is subarachnoid blood from birth trauma interacting with an anatomically immature cerebrospinal fluid-absorbing system. To test this hypothesis and to create a model that could be used to devise various methods of prophylaxis and therapy, we injected autologous blood into the cisterna magna of puppies, followed the size of their ventricles with serial computerized tomographic (CT) scans, and evaluated the scanning electron microscopic (SEM) appearance of the ventricular walls and subarachnoid space. By injecting blood until the dogs were just at the point of apnea, we obtained a 46% incidence of hydrocephalus with a 13% mortality rate. The amount of blood accepted was variable. The size of the ventricles was followed with CT scans; the time course of hydrocephalus was variable, and in some cases it resolved. SEM revealed significant regional, free cell aggregation and calcification, especially over the base of the brain, which was most marked in the animals that developed hydrocephalus. This suggests a more marked reaction or a lesser ability to clear the subarachnoid blood in those animals, although the reason for this is not clear. Possible uses for this model are suggested.

Absorption↗
PubMed1980

Conversion of triglycylvasopressin to lysine-vasopressin in man.

The concentrations in plasma of triglycl-8-lysine-vasopressin (TGLVP), determined by radioimmunoassay, and lysine-vasopressin, determined by bioassay, have been monitored in five subjects after intravenous (7.5 micron/kg) or intranasal (5 mg) administration of TGLVP. The level of excretion in urine was also measured. The TGLVP concentration in plasma fell rapidly after the intravenous injection, the mean half-time of disappearance being 24.2 +/- 1.9 (S.E.M.) min (d.f. 4). Biologically active lysine-vasopressin reached a peak between 60 and 120 min. A similar pattern was seen following intranasal instillation but only a small proportion of the administered dose appeared in the plasma and the concentration of lysine-vasopressin was relatively higher. Less than 1% of the TGLVP injected appeared in the urine. Intravenous TGLVP had no effect on systolic blood pressure but produced an increase in diastolic blood pressure of 1.7 +/- 0.19 kPa (d.f. 4) and a fall in heart rate of 9 +/- 2.3 beats/min. Creatinine clearance and sodium excretion remained relatively constant in all subjects throughout the study but intravenous injection of TGLVP resulted in an antidiuresis which was evident within the first hour of observation and was maintained for a further 4 h. It was concluded that TGLVP is converted to lysine-vasopressin in man and after an intravenous injection of 7.5 micron/kg sufficiently high concentrations of lysine-vasopressin may be maintained for 2 h to produce sustained vasoconstriction. Tryglycylvasopressin may therefore be of value in controlling haemorrhage.

Administration, Intranasal↗
PubMed1980

Clonidine-induced diuresis in the rat: evidence for a renal site of action.

Clonidine, an alpha adrenergic agonist which causes a diuresis in experimental animals, was studied in unanesthetized, conscious Brattleboro rats heterozygous or homozygous for hereditary hypothalamic diabetes insipidus to determine if the diuresis was due to alpha adrenergic inhibition of antidiuretic hormone (ADH) release or to another mechanism of action. Heterozygous rats given clonidine s.c. in doses of 50 to 300 mu/kg b.w. exhibited a prompt dose-related diuresis. The diuresis was transient and could not be maintained beyond 4 hr even when clonidine was administered continuously by s.c. osmotic minipump. In response to clonidine-induced diuresis, plasma osmolality increased acutely from 300 +/- 1 to 310 +/- 1 mOsM/kg by 60 min after injection. Base-line plasma ADH was 5.1 +/- 0.9 mu/ml, remained unchanged at 15 min after clonidine injection but increased to 21.6 +/- 7.2 muU/ml by 60 min and was accompanied by an increase in urinary ADH excretion from 19.6 +/- 3.7 to 48.6 +/- 5.3 muU/hr. In parallel with the drug-induced diuresis, there was an increase in urinary excretion of creatinine, sodium and total solute. The alpha blocking agent phenoxybenzamine did not prevent the diuresis after clonidine injection. Clonidine antagonized the antidiuresis after clonidine injection. Clonidine antagonized the antidiuretic action of ADH administered to rats homozygous for diabetes insipidus. Thus, clonidine-induced diuresis does not appear to be due to alpha adrenergic inhibition of ADH release but rather to direct renal effects.

Animals↗
PubMed1980

The role of the medical school dean's wife: report of a study.

The role of the medical school dean's wife was studied through a questionnaire distributed to wives of U.S. medical school deans. Responses of the wives are presented and discussed. Topics discussed include role orientation, perceived expectations, activities, resources, priorities, and satisfaction. A conceptual model is presented in the form of a three-part typology to describe the approaches used by wives as they play the role. The typology deals with the initiation, extent, and degree of role involvement in medical school activities by the wife of the dean.

Administrative Personnel↗