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Biomedical subjects

S H Miller

Publications and source records attributed to S H Miller.

At least 19 recordsLinked to original sources

Do forehead lifts lift or unfurl?

Forehead lifts are becoming increasingly more popular as an adjunct to facial rejuvenation. Considerable confusion exists as to how much the eyebrow should be elevated and how much scalp should be removed to achieve this goal. In an effort to evaluate this question, we have reviewed our recent forehead lift experience. These were done with forehead flap dissection down to glabella and supraorbital ridge, partial resection of corrugator supercilii, procerus, and frontalis muscles, and limited skin resection. We suggest that a natural-appearing, rejuvenating forehead lift should unfurl facial wrinkles without excessive eyebrow elevation. Technical maneuvers to obtain this goal are discussed.

Forehead

Complications of nasoenteral tubes. Intragastric tube knotting and intragastric tube breakage.

We report two complications of nasoenteral tubes. A nasogastric tube became knotted during gastric intubation in a patient with a small gastric remnant, created during gastric surgery for morbid obesity. A clogged Dobbhoff tube ruptured while it was being flushed manually with a syringe containing normal saline under great pressure. To retrieve the knotted tube, we grasped the distal knotted part visible in the oropharynx with forceps, pulled it out of the mouth, and cut it. To retrieve the broken tube, we snared the intragastric fragment at endoscopy. These case reports suggest that a small gastric remnant may be a risk factor for nasogastric tube coiling and knot formation and that flushing a clogged tube at high pressure may rupture it. To prevent these complications, a nasogastric tube should be carefully passed just into the stomach in a patient with a small gastric remnant, and a clogged feeding tube should be flushed with only moderate pressure. Failure to clear a blocked tube by flushing with normal saline at moderate pressure should lead to tube removal and not to use of excessive pressure.

Adult

Gastric lesions in the excluded gastric segment undetected by endoscopy or radiography in patients status post vertical banded gastroplasty.

A patient had two surgical revisions and another patient had one surgical revision of a vertical banded gastroplasty because of intraoperative findings of gastric ulceration, incomplete penetration, and transmural penetration of the silicone band. Preoperative esophagogastroduodenoscopy in all three cases and an upper gastrointestinal series in two of the cases failed to demonstrate these lesions, because the lesions were located in the surgically excluded gastric segment. These reports demonstrate that a normal upper gastrointestinal series or panendoscopy in a patient after vertical banded gastroplasty does not exclude significant lesions in the endoscopically inaccessible, excluded gastric segment, and that it may be necessary to perform a laparotomy on a severely symptomatic patient even when an endoscopy is normal.

Adult

Studies with abanoquil (UK-52,046) a novel quinoline alpha 1-adrenoceptor antagonist: II. Duration of action, pharmacokinetics and concentration-effect relationships in normotensive subjects.

1. This study further examines the quinoline-derivative abanoquil with particular respect to the duration of its alpha 1-adrenoceptor antagonist activity and its concentration-effect relationship following a single intravenous bolus dose of 0.5 micrograms kg-1 in young, normotensive males. 2. alpha 1-adrenoceptor antagonism (as assessed by phenylephrine pressor responses) was detectable for up to 12 h post dosing: at 12 h there was a significant 1.5-fold rightward shift (95% CI: 2.2 to 1.1) of the pressor dose-response curve for diastolic blood pressure. 3. Despite evidence of substantial alpha 1-adrenoceptor antagonism abanoquil had no significant effect on blood pressure, supine and erect, but there were small and statistically significant increments in heart rate. 4. The degree of alpha 1-adrenoceptor antagonism was related to whole blood concentrations abanoquil: the PD-ratios of phenylephrine pressor responses performed at 1, 6, and 12 h post dosing were significantly correlated with log drug concentrations (r = 0.57 for systolic (P less than 0.05) and r = 0.78 for diastolic blood pressure (P less than 0.005). 5. In conclusion, abanoquil produced significant alpha 1-adrenoceptor antagonism which was related to circulating drug concentrations. The absence of other significant cardiovascular effects suggests that abanoquil warrants further clinical study as an antiarrhythmic agent.

Adrenergic alpha-Antagonists

Chronic swim stress enhances the motoric inhibiting effects of a muscarinic agonist.

The authors previously demonstrated that chronic inescapable swim stress and footshock increase the capacity of a fixed dose of a muscarinic agonist to produce hypothermia in the rat. This project was designed to determine whether chronic inescapable swim stress in cold water would render a low dose of a muscarinic agonist, devoid of an effect on motor behavior in the naive rat (i.e., prior to subjection to the course of swim stress), an inhibitor of mobility. The study involved two groups of rats, an experimental group which received arecoline and a control group which received saline five minutes prior to being placed in an open field. Number of crossings, the dependent variable, was measured in both groups before and after a 14-day course of twice daily inescapable swim stress of 10 minutes duration at 12 degrees C. The arecoline-treated group, as hypothesized, exhibited a significantly greater reduction in number of crossings than the saline-treated groups following the course of swim stress.

Animals

Effects of tourniquet ischemia and postischemic edema on muscle metabolism.

In vivo interstitial muscle pressures measured by wick catheter, tissue gas tensions measured by mass spectrometer, and glucose and high-energy phosphate metabolism measured fluorometrically were studied in the anterior tibial (AT) and vastus lateralis (VL) muscles of primate limbs during and following tourniquet ischemia (2.5 hours; 400 mm Hg) to elucidate postischemic edema and its metabolic consequences. During ischemia, interstitial pressure in the VL rose, while in the AT it decreased, but 24 hours later pressures in both experimental muscles were significantly greater than those in the controls. In both experimental muscles PO2 decreased significantly within 15 minutes of ischemia. PCO2 increased significantly in the AT at 30 minutes and at 75 minutes in the VL muscle. Twenty-four hours later only PO2 in the experimental AT was significantly different than its matched control. During ischemia glucose and phosphocreatine (CrP) decreased significantly, and G-6-P and lactate increased significantly in both muscles, but at 24 hours glucose levels were 25% lower and G-6-P 16.2% higher in the experimental AT and CrP 34% lower in the experimental VL. This study shows that there are significant acute and delayed alterations in primate muscle metabolism following tourniquet ischemia and suggests that these changes may be related to the anatomic location of the muscle studied and the type of trauma it has sustained.

Animals

Hemangioma of the temporalis muscle: a case report and review of the literature.

Hemangiomas are the most common benign tumors of infancy and childhood. Most involve skin and subcutaneous tissues and are readily visible. Intramuscular hemangiomas are very uncommon, and rarely appear in the musculature of the head and neck. A 59-year-old woman who had had a lipoma excised from her left temporal region many years earlier underwent excision of a hemangioma of the left temporalis muscle. Intramuscular hemangiomas do not spontaneously involute and should be removed as soon as they are diagnosed, in order to obviate later destruction of the involved muscle and adjacent tissues. Preoperative embolization of the hemangioma may reduce intraoperative hemorrhaging.

Eyeglasses

Intravascular coagulation and fibrinolysis within primate extremities during tourniquet ischemia.

A common although infrequently recognized complication associated with the use of a pneumatic tourniquet is profuse bleeding from the wound after deflation of the tourniquet. The purpose of this study was to determine whether intravascular coagulation and fibrinolysis could be induced in subhuman primates by tourniquet ischemia, and whether this phenomenon could be altered by pretreatment of the animal with heparin. It was shown that, after 2(1/2) hours of tourniquet ischemia, (400 mmHg) to one lower limb, fibrinogen levels were significantly lower (p < .005), antithrombin III levels were significantly lower (p < .05), plasminogen levels were significantly lower (p < .05), fibrin split products significantly higher (p < .025) and fibrinopeptide A levels were significantly higher (p < .02) than values measured simultaneously in the control limbs. After pre-treatment with sodium heparin, 30 units/kg, there was no change in antithrombin III levels or fibrinogen levels, but fibrin split products in the experimental limbs were significantly elevated (p < .05) when compared to control limbs. In both groups the abnormal levels returned to control levels 5-30 minutes after tourniquet deflation. We conclude that intravascular coagulation and fibrinolysis develop within ischemic subhuman primate limbs during tourniquet ischemia. Pretreatment with heparin prevents the consumption of fibrinogen and antithrombin III but does not prevent the increase in fibrin split products which was observed. It is possible that intravascular coagulation and fibrinolysis contribute to post tourniquet bleeding.

Animals

The effects of reserpine on microcirculatory flow in rat flaps.

A model flap was developed in the rat which allowed us to quantitate microcirculatory blood flow within a flap, and to correlate the flow with the length of flap eventually surviving. A critical flow of 0.02 and 0.03 ml/min/gm (measured during the first 24 hours after flap elevation by radioactive microspheres) appears to be necessary for tissue survival. Reserpine, in a dose of 5 mg/kg, did not increase blood flow in the flap or the length of flap surviving in this model.

Animals

Long-term survival with thorotrast cervical granuloma.

Thorium dioxide, a radioactive contrast material, was commonly used for cerebral angiography prior to recognition of its radiation hazard. Extravasation of the material into the extravascular tissue in the neck results in granuloma formation, thorotrastoma, long-term morbidity, and an increased incidence of benign and malignant tumors. We report our experience with the management of 2 patients who underwent cerebral angiography with thorotrast more than 25 years ago. Aggressive surgical excision of involved tissue is warranted to ameliorate symptoms and diminish the risk of malignancy.

Adult

The acute effects of tourniquet ischemia on tissue and blood gas tensions in the primate limb.

Tourniquet ischemia results in tissue hypoxia which has been measured indirectly by blood gas analysis. The Medspect mass spectrometer allows direct measurement of gas tension in different tissues and may provide more useful information regarding safe tourniquet times. Calibrated Teflon catheters were inserted into the subcutaneous tissue (11 animals), tibial medullary cavities (bone) (nine animals), and tibialis anterior muscles (10 animals) in both lower extremities of anesthetized stumptail monkeys. Tourniquet ischemia was maintained for 1 hour at 400 mm Hg. Tissue and venous blood gas tensions were recorded from both limbs for 1 1/2 hours. Comparisons between gas tensions in each tissue group were made on the basis of their percentage change from control values. In the ischemic limb within 5 minutes muscle PO2 fell 42 +/- 4% (p is less than 0.001), whereas bone and subcutaneous PO2 dropped 25 +/- 4% (p is less than 0.05). Blood PO2 fell 29 +/- 3% and differed only from that of muscle (p is less than 0.01). One hour after tourniquet inflation, blood PO2 levels has fallen 90 +/- 5% (p is less than 0.001) from their control. Changes in tissue PCO2 were less dramatic and did not vary significantly from those recorded in venous blood. After deflation, blood PO2 exceeded its control by 20 +/- 6% (p is less than 0.005) in 5 minutes, but tissue tensions remained 50 +/- 6% below their control values. These studies indicate that tissue gas tensions are a more sensitive indicator of tourniquet hypoxia than are blood gases within the ischemic extremity.

Animals

Power take-off injuries.

Power take-off injuries are uncommon, but serious and potentially fatal. Seven cases are reported demonstrating the violent trauma that can be incurred. The danger associated with use of machines with this and other power equipment is emphasized. Safety shields should be improved, and operators educated about the importance of retaining the shields and using machinery properly at all times.

Accidents, Occupational