Anterior Interosseous Nerve to Ulnar Nerve Transfer: A systematic review

Background

Objectives

Methods

Results

Conclusion

Earlier identification of seriously ill patients: an implementation case series

OBJECTIVE

To describe the strategies used by a collection of healthcare systems to apply different methods of identifying seriously ill patients for a targeted palliative care intervention to improve communication around goals and values.

METHODS

We present an implementation case series describing the experiences, challenges and best practices in applying patient selection strategies across multiple healthcare systems implementing the Serious Illness Care Program (SICP).

RESULTS

Five sites across the USA and England described their individual experiences implementing patient selection as part of the SICP. They employed a combination of clinician screens (such as the 'Surprise Question'), disease-specific criteria, existing registries or algorithms as a starting point. Notably, each describes adaptation and evolution of their patient selection methodology over time, with several sites moving towards using more advanced machine learning-based analytical approaches.

CONCLUSIONS

Involving clinical and programme staff to choose a simple initial method for patient identification is the ideal starting place for selecting patients for palliative care interventions. However, improving and refining methods over time is important and we need ongoing research into better patient selection methodologies that move beyond mortality prediction and instead focus on identifying seriously ill patients-those with poor quality of life, worsening functional status and medical care that is negatively impacting their families.

Palatability and dietary restraint: effect on cephalic phase insulin release in women

The palatability of food has been shown to influence the cephalic phase reflexes. To determine if food palatability affects the magnitude of cephalic phase insulin release (CPIR) in humans, normal-weight women were asked to list foods that they found palatable and unpalatable. Subjects then stayed overnight in the hospital on two separate days. On each morning following an overnight fast, an intravenous line was inserted and arterialized venous blood drawn for the measurement of plasma insulin and glucose. Blood samples were taken prior to and following a modified sham-feed. Subjects sham-fed the palatable or unpalatable foods (that they had previously identified) for a 2-min period. Foods were administered in a counterbalanced order. During the protocol, hunger and food palatability were monitored. The Three Factor Eating Questionnaire was administered to assess eating attitudes. No significant difference in the magnitude of cephalic phase insulin release was found between the two treatments. However, a statistically significant correlation (r = 0.61, p < 0.05) was found between an individual's degree of dietary restraint as measured by the Three Factor Eating Questionnaire and the magnitude of CPIR. These data suggest that the sensory attributes of food may play less of a role in modulating CPIR than an individual's psychological attitude towards food.

Oral sensory stimulation improves glucose tolerance in humans: effects on insulin, C-peptide, and glucagon

In animals, bypassing the oropharyngeal receptors by intragastric administration of glucose results in glucose intolerance. To determine whether the absence of oral sensory stimulation alters glucose tolerance in humans, we monitored plasma levels of glucose and hormones after intragastric administration of glucose, with and without subjects tasting food. Plasma glucose area under the curve (AUC) was significantly lower after oral sensory stimulation (3,433 +/- 783 vs. 5,643 +/- 1,397 mg.dl-1. 195 min-1; P < 0.03; n = 8). Insulin and C-peptide AUCs were higher during the first one-half of the sampling period (insulin, 5,771 +/- 910 vs. 4,295 +/- 712 microU. ml-1.75 min-1; P < 0.05; C-peptide, 86 +/- 10 vs. 66 +/- 9 ng.ml-1. 75 min-1; P < 0.03) and lower during the second one-half of the sampling period compared with the control condition (1,010 +/- 233 vs. 2,106 microU.ml-1. 120 min-1; P < 0.025; 31 +/- 8 vs. 56 +/- 18 ng.ml-1. 120 min-1; P < 0.05; insulin and C-peptide, respectively). Oral sensory stimulation markedly increased plasma glucagon compared with the control condition (1,258 +/- 621 vs. -2,181 +/- 522 pg.ml-1. 195 min-1; P < 0.002). These data provide evidence in humans that oral sensory stimulation influences glucose metabolism and suggest that the mechanisms elicited by this cephalic stimulation are necessary for normal glucose homeostasis.

Sweet taste: effect on cephalic phase insulin release in men

To determine whether sweet-tasting solutions are effective elicitors of cephalic phase insulin release (CPIR) in humans, two studies were conducted using nutritive and nonnutritive sweeteners as stimuli. Normal weight men sipped and spit four different solutions: water, aspartame, saccharin, and sucrose. A fifth condition involved a modified sham-feed with apple pie. The five stimuli were administered in counterbalanced order, each on a separate day. In study 1, subjects tasted the stimuli for 1 min (n = 15) and in study 2 (n = 16), they tasted the stimuli for 3 min. Arterialized venous blood was drawn to establish a baseline and then at 1 min poststimulus, followed by every 2 min for 15 min and then every 5 min for 15 min. In both study 1 and study 2, no significant increases in plasma insulin were observed after subjects tasted the sweetened solutions. In contrast, significant increases in plasma insulin occurred after the modified sham-feed with both the 1 min and 3 min exposure. These results suggest that nutritive and nonnutritive sweeteners in solution are not adequate stimuli for the elicitation of CPIR.

Cannabinoids and appetite stimulation

Appetite stimulation by cannabinoids is highly variable. Four within-subject design studies explored the effects of age, gender, satiety status, route of drug administration, and dose on intake. One study involved a single oral administration of active drug (15 mg males, 10 mg females) or placebo to an age and gender stratified sample of 57 healthy, adult light marijuana users. Eleven subjects received single doses by oral, sublingual, and inhaled routes in a second study. In the third study, 10 subjects ingested a single oral dose in fasted and fed states. A 2.5 mg dose was administered b.i.d. for 3 days by oral and rectal suppository routes in the fourth study. Mean daily energy intake was significantly elevated following chronic dosing by rectal suppository, but not oral capsule, relative to all acute dosing regimens except inhalation. Total daily energy intake was comparable on fed and fasted days, suggesting satiety mechanisms were not impaired by the drug. Subject age, gender, reported "high," and plasma drug level were not significantly associated with drug effects on food intake.

Effects of cannabinoids (marijuana) on taste intensity and hedonic ratings and salivary flow of adults

Cannabinoids purportedly improve taste responsiveness and enhance the sensory appeal of foods. These properties and a commonly cited oral drying effect were evaluated in a series of studies with 'light' marijuana users. The first was a double-blind, placebo-controlled, acute oral dosing trial, involving an age and gender stratified sample of 57 adults. An influence of route of drug delivery was explored in another 11 individuals who were administered a single dose orally, sublingually and via cigarette. To explore effects following chronic administration, six additional individuals were dosed twice per day for 3 days orally and by rectal suppository. Taste intensity and hedonic responses for sweet, sour, salty and bitter food stimuli were monitored at baseline, 2, 4 and 6 hours post-dosing in the acute studies, and daily in the chronic study. Stimulated saliva samples were collected at these same times. Salivary flow rate was significantly negatively correlated with plasma drug levels, and reported 'high' 2 and 4 h post-dosing. No effects of the drug were observed on taste responses. Self-reported shifts in taste responsiveness and hedonics may be related to alterations of memory and cognition, rather than gustatory function.

Oral sensory stimulation in men: effects on insulin, C-peptide, and catecholamines

To investigate the effect of oral sensory stimulation on cephalic phase insulin release (CPIR) and other compounds associated with glucose metabolism, a modified sham feed was used in which male subjects (n = 15) tasted, chewed, and then expectorated the food stimulus. Subjects remained fasted, sham fed, or ingested food on separate days over a 5-day period. After four baseline blood samples, poststimulus samples were taken every 2 min for 14 min and then every 15 min for 2.25 h. Increases in plasma insulin and C-peptide were found during the cephalic phase time period (0-10 min poststimulus) on the sham-fed and fed conditions when compared with fasted values. Glucose, norepinephrine, epinephrine, and free fatty acids were not affected by oral sensory stimulation or food ingestion during the cephalic phase period. The magnitude and profile of CPIR were similar after sham feeding and food ingestion. This study demonstrates that oral sensory stimulation can elicit CPIR in humans independently of changes in blood glucose.

Cephalic-phase insulin in obese and normal-weight men: relation to postprandial insulin

Cephalic-phase insulin release (CPIR) and its relation to postprandial insulin release were examined in 18 normal-weight and 15 obese men. When the insulin data were expressed as absolute differences from baseline values, obese subjects exhibited significantly greater CPIR than normal-weight subjects (normals, 8.7 +/- 2.1 microU/mL/10 min; obese, 13.4 +/- 4.3 microU/mL/10 min; P < .01). Obese subjects were then separated into groups depending on their fasting insulin levels. This showed that only those subjects with elevated fasting insulin levels exhibited greater CPIR than normal subjects, and suggested that previous reports of exaggerated CPIR in the obese are merely a reflection of a basal hypersecretion of insulin. However, when insulin values were expressed as percentages of baseline, no significant differences between normal-weight and obese subjects were found, although a trend toward an attenuated response was observed in the obese group as a whole (normals, 81.6 +/- 19.1 microU/mL/10 min; obese, 51.3 +/- 16.1 microU/mL/10 min). A significant correlation between cephalic-phase and postprandial insulin release was found in normal-weight subjects (r = .62, P < .05), but not in obese subjects (r = .02, P < .9).

Bypassing the first-pass effect for the therapeutic use of cannabinoids

An oral formulation of delta-9-tetrahydrocannabinol (THC) in sesame oil (Marinol) is at present used for the management of chemotherapy-related nausea and emesis. However, due partly to poor bioavailability, its efficacy is variable. To circumvent possible metabolism in the gut and a first-pass effect by the liver, a suppository formulation of THC hemisuccinate ester was prepared. Administration of the suppository containing 11.8 mg of the hemisuccinate ester (equivalent to 9 mg THC) to three adult females (two of whom had previously exhibited low plasma drug levels following a 10-mg dose of the oral formulation) led to a marked and sustained elevation of plasma drug levels. Areas under the curves for plasma THC were more than 30-fold higher than after oral dosing. The suppository was well tolerated. The higher and more sustained plasma drug level achieved with this new formulation should enhance its antiemetic efficacy.

Effects of combined hydrochlorothiazide and amiloride versus single drug on changes in salt taste and intake

Hydrochlorothiazide stimulates salt intake without altering salivary or gustatory function. Amiloride reportedly reduces salivary sodium levels and salt taste. It was hypothesized that these unintended drug actions would be attenuated by concurrent use of these 2 diuretics. Normotensive adults (n = 23) were administered placebo for 2 weeks, active combination drug Moduretic for 4 weeks, and placebo again for 2 weeks in a double-blind protocol. Salivary flow, gustatory function and sodium intake were monitored at the end of each period, together with selected physiologic measures (i.e., plasma aldosterone, plasma renin activity, body composition, blood pressure and heart rate). No significant changes were observed for salivary flow, salt taste or sodium intake. These findings indicate that amiloride and hydrochlorothiazide used in combination can reduce drug effects that may compromise the efficacy of either drug when used alone.

Cephalic phase insulin release in normal weight males: verification and reliability

The existence and reliability of cephalic phase insulin release (CPIR) were tested in 20 normal weight males. Each subject was challenged three times with the same food stimulus over a 5-day period. Four baseline blood samples were taken at 5-min intervals before food ingestion and then every 2 min for 16 min postingestion. Significant increases in plasma insulin were found at 4 min postingestion on each trial day. CPIR was found to be highly reproducible between trials (r = 0.83; P less than 0.001). Fifty percent of the subjects exhibited a significant increase of plasma insulin above their own baseline mean on the first trial, whereas 75 and 72% exhibited increases on trials 2 and 3, respectively. Only two subjects (10%) did not demonstrate a response on any trial. A significant decline in plasma glucose was observed at 4 min postingestion on trials 2 and 3. No significant changes in plasma glucagon were found during any trial day. This study confirms a reliable CPIR in normal weight males.

Naltrexone, an opioid blocker, alters taste perception and nutrient intake in humans

To test the hypothesis that reduced food intake produced by opioid blockade is due to a reduction in the pleasant aspects of tastes, 18 fasted male college students rated the intensity and pleasantness of soup that contained various concentrations of NaCl and of Kool-Aid that contained various concentrations of sucrose at hourly intervals after ingesting either naltrexone (50 mg) or a placebo in a double-blind study. Hunger, fullness, nausea, and current mood state were also assessed. Lunch followed and food intake was recorded. After placebo, the pleasantness of the salted soup increased as lunchtime approached. After naltrexone, however, soup pleasantness remained unchanged across time. Similar changes were obtained for perceived sweetness and pleasantness of Kool-Aid and for the perceived saltiness of soup. Naltrexone also blocked the increases in hunger ratings that occurred across time in the placebo condition. Nausea was higher after naltrexone. After naltrexone, subjects consumed approximately 500 kcal less at lunch than after placebo. Analysis of covariance suggested that decreased hunger (but not nausea or taste pleasantness) accounted for the naltrexone-induced reduction of food intake.

High salt intake. Sensory and behavioral factors

Salt (NaCl) is a ubiquitous component of diets in developed countries. A major reason for this is that people judge many salted foods as more palatable than the same foods without salt. Because recent evidence indicates that an acceptable salt substitute is unlikely, an understanding of the behavioral and sensory factors involved in maintaining high salt preference is a prerequisite to successful programs aimed at reducing intake. Although little evidence exists for a genetic determination of individual differences in consumption and preferred level of salt, more research in this area is necessary. Considerable data support the view that the optimal level of salt in the diet is determined in part by the level an individual is currently consuming; increasing or decreasing customary salt intake, as long as the salt is tasted, increases or decreases the preferred level of salt in food. Although these data are consistent with a hypothesis that optimal salt preferences are learned, other data, from both animal models and human developmental studies, suggest that salt preference has an innate component. Furthermore, early experience with low or high salt diets may have a long-term impact on preferred salt levels. Liking for salt, similar to liking for sweets, has an innate basis that can be modified by individual experience.

Effects of hydrochlorothiazide and amiloride on salt taste and excretion (intake)

The effects of hydrochlorothiazide (HCTZ) and amiloride on salt excretion (intake) and taste were examined in 73 normotensive adults (aged 18 to 56) who were randomly assigned to receive 50 mg/day of HCTZ (n = 24), 5 mg twice daily of amiloride (n = 24) or placebo (n = 25) for 8 weeks. Two and three week placebo periods preceded and followed active treatment, respectively. Relative to baseline, significant increases in sodium excretion (intake) of 31%, 53% and 30% were observed in subjects receiving HCTZ after 2, 4 and 8 weeks of treatment, respectively. An identical follow-up study with 16 subjects replicated the sodium excretion (intake) findings, but failed to reveal the source of the extra dietary sodium. Doubling the dose of amiloride in 11 additional subjects led to higher aldosterone excretion relative to thiazide-treated subjects, but did not increase salt excretion (intake) over a four week period. Only amiloride-treated subjects displayed significant increases in salt taste sensitivity. The increased sodium intake in HCTZ-treated patients may partially offset the desired effects of therapy and exacerbate potassium wasting.

Experimental sodium depletion and salt taste in normal human volunteers

To examine the sensory effects of extreme sodium depletion in humans, 10 normal volunteers were fed a very-low-sodium diet and were treated with diuretics for 10 d. Urine samples were collected and blood was drawn for hormone analyses. Taste tests included threshold and intensity judgments of salt (NaCl) and sucrose and preferences for salt and sucrose in foods. Subjects also rated the pleasantness of 29 foods listed on a questionnaire. Substantial sodium depletion was induced in all subjects. Salt thresholds decreased in a majority of the subjects whereas preference judgments for salt in foods tended to be greater during the depletion period. The changes in pleasantness of the 29 foods revealed that saltier foods were substantially more attractive during the depletion period than during the pre- and postdepletion periods. These data indicate that experimental sodium depletion in humans is followed by moderate sensory changes and an increased preference for salty foods.

Localization of pheochromocytoma: MIBG [correction of MIGB], CT, and MRI correlation

Nineteen patients (8 M, 11F) ranging in age from 15 - 67 yr old (mean = 39 yr) with clinically diagnosed pheochromocytomas were prospectively evaluated with 131I metaiodobenzyl-guanidine (MIBG) scintigraphy (n = 19), computed tomography (CT) (n = 19), and magnetic resonance imaging (MRI) (n = 17) in order to determine their relative diagnostic efficacy. Pathologic confirmation was obtained in all 19 patients: 13 intraadrenal and six extraadrenal with metastases in five (Table 1). All three imaging modalities were in agreement in 11 of 14 completed examinations (79%). MIBG and CT agreed in 16 of the 19 patients in whom both were performed (84%). MIBG/MR and CT/MR results were concordant in 12 of 14 (86%) and 13 of 14 (93%) jointly completed examinations, respectively. There was one false-negative (FN) MIBG scan, two FN CT scans, and one FN MR scan. MIBG, CT, and MRI are complementary procedures with MIBG providing more specific functional information and the latter two superior anatomic detail. MIBG scintigraphy is recommended as the initial localizing study of choice (especially for the detection of extraadrenal disease and postoperative recurrence), as a guide for CT and/or MR and specific functional confirmation of their findings. Although MRI is capable of imaging in multiple planes (without exposure to ionizing radiation or the need for i.v. contrast material) with superior contrast compared to CT, it is expensive and has poor patient cooperation. However, it may be capable of differentiating pheochromocytomas from other adrenal masses on the basis of signal characterization.

Side effects of sympatholytic antihypertensive drugs

Antihypertensive drugs with pharmacological action due to sympatholytic activity have been second only to diuretics in their use and efficacy in normalizing blood pressure. Their pharmacological actions have resulted in the notable absence of chemical toxicity, but because of symptomatic side effects, their use has been limited relative to some of the newer antihypertensive agents. Most prominent among undesirable side effects are the central nervous system findings of sedation, altered thought process, depression, and orthostatic or exercise hypotension. Sexual problems, especially in men, are also prominent. Special toxicity is discussed with reference to methyldopa, clonidine, monoamine oxidase inhibitors, and metyrosine.

Failure to compensate decreased dietary sodium with increased table salt usage

This study tested the extent to which individuals placed on a lowered sodium diet would compensate for the reduced dietary sodium by adding table salt to their food. Eleven students, unaware that their use of saltshakers was being studied, consumed all their meals and snacks in a clinical research center for 13 weeks. During the first three weeks and the last week (week 14), the diet contained approximately 135 mmol/d (135 mEq/24 h) of sodium, which was reduced to approximately 70 mmol/d (70 mEq/24 h) during weeks 4 through 13. A preweighed saltshaker was available for use throughout the entire 14-week period. Evaluations of salt taste preference and intensity scaling were conducted at regular intervals. Subjects compensated only slightly for the reduction of dietary sodium, making up less than 20% of the decrement with increased saltshaker usage. No changes in taste function were found. A substantial reduction in dietary sodium is possible if lowered-sodium foods are consumed in conjunction with ad libitum table salt.

Fluorometric documentation of increased cutaneous blood flow after topical application of a PGE2 analog in man

The present study employed fiberoptic fluorometry, a noninvasive means of documenting delivery and removal of fluorescein dye, to evaluate the local circulatory changes elicited by topical application of DHV-PGE2 ME, an investigational PGE2 analog. On Day 1, inactive vehicle was applied to a 5 X 4 cm study site on each thigh of healthy volunteer subjects (n = 12). Symmetrical perfusion was confirmed by similar determinations of dye delivery and removal at each site. On Day 2, DHV-PGE2 ME, 30 or 120 micrograms, was applied to one site while inactive vehicle again was applied to the other. After administration of 120 micrograms in a petrolatum vehicle, fluorometry detected a pronounced increase in nutritive perfusion. There was significant acceleration of dye delivery and removal (p less than 0.05 by ANOVA). Less pronounced changes were noted after the lower dose of DHV-PGE2 ME and when the drug was applied in a triethyl citrate vehicle. The local circulatory changes were not accompanied by systemic effects; there were no changes in vital signs or in fluorometric indices at remote sites.

The influence of moderate reduction in dietary sodium on human salivary sodium concentration

Twenty-four healthy subjects were placed for 12-13 weeks on diets that reduced average sodium intake from 145 to 74 m-equiv. Na+/day as determined by multiple 24-h urine collections before and during the diet. Whole-mouth resting and stimulated saliva was collected and analysed for flow rate and sodium concentration several times before and during the low-sodium period. Sodium restriction did not influence salivary flow rates but salivary sodium levels fell 25 per cent for resting and 17 per cent for stimulated saliva. Thus moderate reductions in sodium intake are accompanied by significantly lower salivary sodium levels.

Increasing dietary salt alters salt taste preference

In previous studies with humans, moderate reduction of dietary sodium decreased preference for salty foods. It had been hypothesized that this occurred via reducing taste stimulation with salty foods. Taste function after increasing dietary salt (NaCl), either with or without increasing salt taste stimulation, was examined in two experiments. In Experiment 1, one group of subjects was required to add crystalline salt to food daily for 4 weeks. A second group ingested salt tablets for the same period. A third group ingested a placebo. Whereas urinary sodium excretion increased in both groups ingesting supplemental salt, the concentration of salt in soup rated as tasting most pleasant increased only in the group adding salt to food. Rated intensity of salt did not change. In Experiment 2, salt supplementation was extended to 6 weeks and taste function was tested more extensively. At the end of the experiment, the concentration of salt in soup rated as tasting most pleasant increased in the group which added the crystalline salt to food. This group also added more salt to soup to taste than did the salt tablet group. The most pleasant concentration of KCl in soup was not significantly affected. Taken together these two experiments suggest that the preferred concentration of salt in soup can be increased after dietary salt supplementation and that increased salt taste stimulation is probably required for this to occur.

Diagnosis of pheochromocytoma

This article reviews the pathophysiology and clinical features of pheochromocytoma, along with the biochemical approaches that have been used for confirming its diagnosis. Different methods for urinary, plasma, and platelet catecholamines and catecholamine catabolites are discussed, and the authors' opinions on which test(s) to use and which patients screen are presented.

Modification of salt taste

Salt appetite and sodium intake in humans are controlled in part by taste. A distinction can be drawn between salt appetite that occurs when the organism is sodium deficient (in need) and when the organism has sufficient sodium stores (non-need) but continues to ingest salt. Although the latter case is most relevant to human sodium consumption, little is known about its physiologic, developmental, and experiential bases. Recent studies show that changes in dietary sodium consumption are followed by taste changes. Moderate decreases in dietary sodium of 2 months or more are followed by a decrease in the concentration of salt in food judged most pleasant.

Long-term reduction in dietary sodium alters the taste of salt

A group of young adult subjects was placed on self-maintained, low sodium diets for 5 months. Taste responses to salt in solutions, soups, and crackers were determined both during the 2 months preceding diet initiation and during a 5-month period when subjects lowered their sodium intake. Taste responses were also determined in a control group with ad libitum salt consumption throughout the same period. Perceived intensity of salt in crackers increased. The salt concentrations of maximum pleasantness in soup and crackers fell in the experimental subjects but not in the control subjects. These results demonstrate that the preferred level of salt in food is dependent on the level of salt consumed and that this preferred level can be lowered after a reduction in sodium intake. The implications of these findings for the maintenance of low sodium diets are discussed.

Adrenal medullary hyperplasia: a clinicopathologic study of four cases

This study presents the clinicopathologic findings in four new cases of adrenal medullary hyperplasia. The patients presented with episodic hypertension frequently associated with palpitations, headache, and diaphoresis. All four had elevated urinary catecholamine levels during attacks, and were thought clinically to have a pheochromocytoma. In each case laparotomy revealed a diffusely enlarged adrenal gland without a discrete tumor. Histologic examination of the adrenals demonstrated a diffuse and nodular expansion of the medulla confirmed by morphometric study. Of the four patients, three underwent unilateral and one bilateral adrenalectomy. Two patients who underwent unilateral adrenalectomy have been free of symptoms for three years. Thus, it would appear that adrenal medullary hyperplasia may occur unilaterally or asynchronously in the two glands. The bilaterally adrenalectomized patient has had persistent attacks, suggesting that the stimulus to adrenal medullary hyperplasia may possible affect other chromaffin tissues. On the basis of our cases and a review of the literature, we propose the following criteria for the diagnosis of adrenal medullary hyperplasia: a clinical history of episodic attacks suggesting pheochromocytoma (generally with associated increased urinary catecholamine levels), an adrenal gland showing diffuse expansion of the medulla into the alae or tail of the gland with or without nodule formation, a medulla composed of enlarged cells with or without pleomorphism, and, most important, an increased medulla/cortex ratio, together with an increased calculated medullary weight as determined by morphometric analysis.

Abrupt discontinuation of clonidine therapy

Clonidine therapy was discontinued abruptly in seven patients. Blood pressure was recorded every hour or two hours throughout the study. Clonidine therapy was reinstituted 48 hours after its discontinuation in all except two patients, in whom it was reinstituted at 36 hours. During the withdrawal phase, blood pressure tended to return rapidly to nontreatment levels, but there was no "overshoot" in blood pressure. Apprehension, insomnia, palpitations, and sweating were experienced by two patients. These symptoms were relieved promptly by reinstituting clonidine therapy. In this prospective study, no blood pressure overshoot was noted with abrupt discontinuation of clonidine.

Pheochromocytoma--recognition and management

Pheochromocytoma is an infrequent cause of hypertension. In spite of its rarity, pheochromocytoma has assumed notorious importance because or a wide variety of clinical features associated with this syndrome. Hypertension remains the most important clinical lead. The presence of other features, such as severe headache, perspiration, palpitations or orthostatic hypotension, makes the diagnosis of pheochromocytoma likely. The diagnosis of this condition can be made with greater certainty than that of any other form of secondary hypertension. Pharmacologic tests are no longer used for evaluation purposes. Biochemical tests are the most important aids to diagnosis, provided highly specific methods are used to determine the levels of urinary catecholamines or their metabolites. Interference by various drugs should be avoided. Most of the pheochromocytomas are found in the abdomen, predominantly in the adrenals. Successful outcome of surgery depends critically on adequate preoperative preparation of the patient with adrenergic blocking drugs and proper intraoperative care. Surgery should only be performed in an institution with experience in treating these tumors. Invasive localizing procedures could be dangerous in patients with pheochromocytoma and are best avoided. Medical therapy proves to be quite successful for those patients who are unable or unwilling to undergo surgery and for those with demonstrated malignant tumor. The postoperative course in most instances is uneventful. The physician should be aware of familial forms of pheochromocytomas and screen all the hypertensive members of the patient's family for the presence of this condition. Pheochromocytoma, with its multiple facets, presents a challenge to the clinician; however, with prompt diagnosis and proper treatment, pheochromocytoma can often be cured. The improved management of patients with this potentially lethal condition is the result of better knowledge of biochemical pharmacology, improved preoperative, surgical and postoperative care.

Failure of alpha-methyltyrosine to inhibit peripheral triiodothyronine formation

To determine if the adrenergic nervous system, and specifically tyrosine hydroxylase, plays a role in the extrathyroidal conversion of T4 to T3, normal male volunteers were treated with T4 and subsequently with T4 and alpha-methyl-p-tyrosine (alpha-MPT), an inhibitor of tyrosine hydroxylase, for 2 weeks. The mean serum T4 and T3 concentrations increased during T4 administration and remained at the same levels during combined T4 and alpha-MPT administration. Urinary vanillylmandelic acid excretion declined significantly during alpha-MPT administration. These results do not support the hypothesis that tyrosine hydroxylase is involved in extrathyroidal T3 production.

Phaeochromocytoma

Factors involved in the evaluation and care of patients with phaeochromocytoma have been discussed with respect to important considerations for the consulting or practising physician. Historical, physical, biochemical and other diagnostic procedures, as well as therapeutic manoeuvres have been adequately documented so that the clinician requiring additional information in depth may seek out the pertinent literature. Utilizing this manner of approach should significantly improve the care of patients with phaeochromocytoma in the hands of physicians who have not themselves had extensive experience with this disease. However, it must be emphasized that because of the potential gravity of this condition, if the physician feels insecure in the care of a patient or has further questions, he should not hesitate to seek expert advice which will benefit both the patient and himself.

Vagally mediated suppression of premature ventricular contractions in man

Twelve patients with PVC's were studied to assess the possible role of the vagus nerves in suppressing PVC's. All were without significant heart disease and under forty years of age. A series of five autonomically active drugs, including vagotonic and vagolytic agents, was administered intravenously, each drug being given after the effects of the previous one had abated. Two of the patients did not have PVC's at the time of study. Of the remaining ten patients, five showed vagally mediated suppression of PVC's. Phenylephrine (40 to 60 mug per minute) reduced HR, from an average of 63.2 bpm to 48.5 bpm by a vagally mediated reflex, and decreased PVC incidence in all five patients. The per cent of ventricular heart beats which were PVC's (per cent PVC) decreased from an average of 18.2 per cent to 3.2 per cent in these patients (p smaller than 0.005 in each case). Edrophonium (10 mg.) produced less bradycardia and less reliable PVC suppression. In two of these five patients, atropine (1.5 mg.) increased PVC incidence markedly, although the per cent PVC did not change significantly because of the concomitant tachycardia. These data suggest that strongly increased vagal tone can suppress PVC's in a significant percentage of such patients. This finding in man extends previous animal work which has shown a protective role of the vagus against ventricular arrhythmias under certain conditions.

Systolic time intervals and left ventricular function in acute myocardial infarction

Systolic time intervals (STI) were measured simultaneously with left ventricular pressure, right atrial pressure, and cardiac output in patients with acute myocardial infarction (AMI) within 24 hours of the onset of symptoms. Electromechanical systole (QS2) and left ventricular ejection time (LVET) were measured and preejection period (PEP) calculated and corrected for heart rate. LVET showed significant correlation with stroke volume (r = 0.62), confirming previous observations. Patients with significantly elevated left ventricular end-diastolic pressure (LVEDP) and clinical signs of congestive heart failure (CHF) usually exhibited a prolonged PEP when compared with normal subjects or patients with AMI who did not have signs of CHF. The normal PEP in the latter group might be due to adrenergic stimulation offsetting the effect of myocardial damage, although measurements of circulating catecholamines did not conclusively support this hypothesis. We conclude that STI are not reliable indices of left ventricular performance in AMI.