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Biomedical subjects

M Miller

Publications and source records attributed to M Miller.

At least 649 records · Page 36Linked to original sources

Synaptic ribbon populations in the pineal gland of the rhesus monkey (Macaca mulatta).

Pinealocytes of rhesus monkeys that had been ovariectomized and given intramuscular injections of 250 micrograms estradiol-benzoate for 3 consecutive days tended to have more synaptic ribbons (SR) and exhibited a significantly greater size of ribbon fields (RF) compared to untreated animals. These data are consistent with hypotheses that pinealocyte function in primates is altered by hormonal imbalances and that the SR participates in this response. RF were positioned in various parts of the cytoplasm and along the plasma membrane. Participation of SR in direct cell-to-cell contacts was suggested by the formation of densities along the plasma membrane. It is postulated that large RF serve as storage organelles and that the formation of RF results from division of pre-existing SR in each field. Reconstructions made from serial thin sections revealed that profiles of RF comprised separate SR that were not folded and sectioned along various planes.

Animals↗

Changes in gait patterns after operations in children with spastic cerebral palsy.

We have utilised a scoring system with the aid of a specially designed worksheet to measure gait ability in spastic children with cerebral palsy before and after corrective soft tissue operations. Postoperatively, there were obvious improvements in gait especially in the mobility of the leg and the foot. Comparison between a visually assessed score and objectively recorded values using foot-switches showed a good correlation. The postoperative improvement was most obvious in hemiplegic children, but was also present in diplegic children following both single and complex one-stage operations.

Adolescent↗

Detailed comparison of regional and general anesthesia for carotid endarterectomy.

Forty-one variables were examined in 75 patients who underwent carotid endarterectomy to determine if significant differences were present between 45 patients who had general anesthesia and 30 patients who had regional anesthesia. The two groups were similar in terms of age, existing medical illnesses, neurologic presentation, and angiographic severity of the carotid lesions. There were no differences between the two groups for operative time, anesthesia time, blood loss, maximum or minimum blood pressures, postoperative hemodynamic data, or the requirement for or duration of intravenous pressor or antihypertensive medications. One patient in the regional group had a postoperative neurologic deficit which resolved in 1 month. Three patients in the general group had cardiovascular complications. Postoperative hospital stay was significantly longer in the general anesthesia group (5.6 to 3.2 days, p = 0.003). Regional and general anesthesia produce similar perioperative hemodynamic and surgical outcomes, but regional anesthesia results in a shorter hospital stay and less cardiovascular morbidity in this high risk population.

Anesthesia, Conduction↗

Increasing handwashing in an intensive care unit.

The present study provides the first systematic evaluation of strategies for increasing handwashing of hospital staff. Nursing staff on two intensive care units (ICUs) were observed over a 3-month period. After baseline observations, two interventions were implemented on the experimental unit: changing to an emollient handwashing agent, and providing feedback to staff about the frequency of handwashing. Feedback focused on the previous day's handwashing following completed patient contacts, interrupted patient contacts, and critical procedures. No increase in handwashing was observed following introduction of the emollient soap. However, when feedback was provided on the experimental ICU, handwashing following completed patient contacts (the major dependent measure) increased to 92%, and was significantly higher than handwashing on the control unit. Follow-up observations suggested that compliance on the experimental unit appeared to return to baseline levels.

Cross Infection↗

Effects of somatostatin analogue SMS 201-995 in normal man.

Long-acting somatostatin analogues may be of benefit in certain hypersecretory endocrine and gastrointestinal disorders. The 24 h hormonal and metabolic profiles of six normal male subjects receiving a twice daily subcutaneous injection of one such analogue SMS 201-995, 50 micrograms, has been compared to that obtained following placebo injection. Spontaneous daytime peaks of GH secretion were delayed until 1400 h following SMS 201-995 but nocturnal and total 24 h GH secretion were unaffected. The nocturnal rise in thyrotrophin was abolished by SMS 201-995 but thyroid function was unaffected. Insulin levels were suppressed following SMS 201-995 and the response to meals was inhibited. Glucose intolerance followed main meals. Glucagon levels were suppressed for up to 6 h. Circulating alanine levels were raised between 1200 h and 0600 h and there were intermittent elevations in lactate, pyruvate, glycerol and 3-hydroxybutyrate. Amino acid levels, including branched chain amino acids, were also increased. All six subjects suffered gastrointestinal side-effects. SMS 201-995, 50 micrograms, given twice daily shortly before meals does not suppress 24 h GH secretion, but demonstrates significant effects on metabolism and causes side effects in normal subjects.

Adult↗

Effects of somatostatin analogue SMS 201-995 in non-insulin-dependent diabetes.

The 24-h hormonal and metabolic profiles obtained in five non-insulin-dependent diabetics receiving twice daily s.c. injections of the long-acting somatostatin analogue SMS 201-995 (50 micrograms) have been compared with those obtained following placebo injection. Injections were given 30 min before breakfast and the evening meal. GH secretion was not suppressed by the analogue administered in this manner. Despite suppression of serum insulin levels following breakfast and the evening meal, blood glucose levels were similar during the two study periods with no evidence of worsening in diabetic control. Prolonged suppression of plasma glucagon levels was observed and the nocturnal elevation in serum TSH levels was abolished. Free T4 levels fell significantly following the analogue but total T3 levels were unaffected. Blood alanine levels were elevated throughout the study period following SMS 201-995 but changes in lactate, pyruvate, glycerol and 3-hydroxybutyrate were minor. All five subjects suffered gastrointestinal side-effects. SMS 201-995 (50 micrograms) given twice daily before meals does not cause a deterioration in metabolic control, does not suppress 24-h GH secretion and causes significant side-effects in patients with non-insulin-dependent diabetes mellitus.

Adult↗

Exercise-induced regional dysfunction with subcritical coronary stenosis.

The hypothesis was tested that regional myocardial contractile dysfunction can detect subtle regional coronary blood flow maldistribution induced by exercise. In seven dogs, left ventricular pressure (micromanometer), regional systolic wall thickening (WTh, sonomicrometry), and myocardial blood flow (MBF, microspheres) were measured when mild degrees of coronary artery stenosis were produced during treadmill exercise. During exercise without coronary stenosis, WTh increased by 21 +/- 12% (SD), and transmural MBF increased uniformly. In each dog, two levels of coronary stenosis were produced during exercise by adjusting the coronary hydraulic cuff: (1) St-Ex I, where WTh during exercise failed to increase significantly (average change 0 +/- 7%), and (2) St-Ex II, where WTh during exercise decreased moderately from the resting control value (average -20 +/- 8%). In the potentially ischemic zone coronary hyperemia occurred with each run: resting subendocardial MBF was 1.09 +/- 0.30 mg/g/min, and it was 3.04 +/- 0.83 during control exercise, 2.48 +/- 0.75 during St-Ex I, and 1.55 +/- 0.59 ml/g/min during St-Ex II (p less than .01 compared with control exercise and control area). The subendocardial-subepicardial blood flow ratio fell from 1.32 +/- 0.27 during control exercise to 1.07 +/- 0.20 (p less than .05) during St-Ex I, and to 0.64 +/- 0.15 (p less than .01) with St-Ex II. Changes in the subendocardial electrogram and reactive hyperemia occurred more consistently during St-Ex II than St-Ex I. Thus, failure of regional function to increase during exercise detected slight maldistribution of regional MBF, whereas reduction of regional function during exercise of 10% or more below the resting value was a reliable marker of a regional flow defect and was always associated with other evidence of ischemia. Therefore, regional dysfunction during exercise can detect subcritical but functionally significant coronary stenosis, which may allow regional wall motion to be used for detecting coronary artery disease at a relatively early stage.

Animals↗

Approaches to the management of soft tissue defects of the malleolar region.

When considering plastic procedures in the malleolar region, it is crucial to remember the special characteristics of this area. The blood supply, the skeletal structure, and the position of the limb all contribute to the uniqueness of this region. The approaches and procedures depend on the nature and size of the defect. By being knowledgeable of the anatomy and intrinsic characteristics of the malleolar region, and adhering to the principles of plastic and tissue handling, the best possible results of soft tissue reconstruction will be obtained.

Bone Neoplasms↗

Bilateral internuclear ophthalmoplegia in systemic lupus erythematosus.

The case of a 25-year-old female with bilateral internuclear ophthalmoplegia as a presenting feature of systemic lupus erythematosus (SLE) is described. It is important to recognize that bilateral internuclear ophthalmoplegia may be an early manifestation of cerebral involvement in SLE in addition to its occurrence in multiple sclerosis.

Adult↗

Nuclear magnetic resonance and neutron diffraction studies of the complex of ribonuclease A with uridine vanadate, a transition-state analogue.

The complex of ribonuclease A (RNase A) with uridine vanadate (U-V), a transition-state analogue, has been studied with 51V and proton NMR spectroscopy in solution and by neutron diffraction in the crystalline state. Upon the addition of aliquots of U-V at pH 6.6, the C epsilon-H resonances of the two active-site histidine residues 119 and 12 decrease in intensity while four new resonances appear. Above pH 8 and below pH 5, these four resonances decrease in intensity as the complex dissociates. These four resonances are assigned to His-119 and His-12 in protonated and unprotonated forms in the RNase-U-V complex. These resonances do not titrate or change in relative area in the pH range 5-8, indicating a slow protonation process, and the extent of protonation remains constant with ca. 58% of His-12 and ca. 26% of His-119 being protonated. The results of diffraction studies show that both His-12 and His-119 occupy well-defined positions in the RNase-U-V complex and that both are protonated. However, while the classic interpretation of the mechanism of action of RNase based on the proposal of Findlay et al. [Findlay, D., Herries, D. G., Mathias, A. P., Rabin, B. R., & Ross, C. A. (1962) Biochem. J. 85, 152-153] requires both His-12 and His-119 to be in axial positions relative to the pentacoordinate transition state, in the diffraction structure His-12 is found to be in an equatorial position, while Lys-41 is close to an axial position. Hydrogen exchange data show that the mobility and accessibility of amides in the RNase-U-V complex do not significantly differ from what was observed in the native enzyme. The results of both proton NMR in solution and neutron diffraction in the crystal are compared and interpreted in terms of the mechanism of action of RNase.

Animals↗