Enalapril versus combined enalapril and nadolol treatment: effects on blood pressure, heart rate, humoral variables, and plasma potassium at rest and during exercise in hypertensive patients

The effect of enalapril alone and in combination with nadolol on resting and exercising blood pressure, heart rate, plasma renin activity, aldosterone, noradrenaline, and potassium levels was studied in 10 hypertensive patients (diastolic blood pressure between 95 and 114 mmHg). Patients received placebo for 4 weeks, enalapril (mean daily dose 24.5 mg) for 8 weeks, and nadolol, 40 mg once daily, was added for the remaining 8 weeks of the study. Exercise testing (modified Bruce, treadmill) was conducted at the end of the placebo run-in phase and at the end of each treatment period. Enalapril reduced resting and exercising blood pressure independent of any change in heart rate: This effect was increased with combination treatment. Plasma renin activity at rest and during exercise was increased by enalapril. Combination treatment attenuated this response and significantly reduced plasma aldosterone. Neither treatment had any effect on plasma noradrenaline levels. Resting plasma potassium levels were increased with combination treatment, whereas both treatment regimens increased plasma potassium levels during exercise. There were no clinically relevant episodes of hyperkalemia. Further investigation is required to qualify the nature of the blood pressure and plasma potassium response with combination treatment.

A secreted beta-glucan-branching enzyme from Candida albicans

A Mr 34,000 wall protein was isolated as a by-product of the purification of an endo-(1-3)-beta-glucanase from the culture filtrate of Candida albicans. The purified fraction contained no exo- or endo-beta-glucanase activity, and analysis by SDS poly-acrylamide gel electrophoresis (SDS-PAGE) showed one protein band at Mr 34,000. Analysis by gel filtration high performance liquid chromatography (HPLC) of reaction products from incubations of the protein fraction with laminarioligosaccharides of five glucosyl units or greater revealed a unique glucanosyl transferase activity. The enzyme specifically cleaved laminaribiaose (G2) from the reducing-end of a linear beta-(1-3)-glucan and transferred the remainder to another laminarioligosaccharide. The reaction with laminaripentaose (G5) produced G2 and a product eluting at the position of G8. Analysis of the latter transferase product by 13C- and 1H-nuclear magnetic resonance (NMR) spectroscopy shows it to be a branched molecule containing a beta-(1-3)-beta-(1-6)-branchpoint. It is suggested that the Mr 34,000 wall protein is a glucan branching enzyme, perhaps the key enzyme responsible for the transformation of the initial linear beta-(1-3)-glucan into the branched beta-(1-3)-beta-1-6)-glucan as found in the cell wall of C. albicans.

Common-sense ethics in administrative decision making. Part II, Proactive steps

This article is the second in a two-part study on common-sense ethics. In Part 1 (October 1991 JONA), the authors presented preparatory steps for the nurse administrator to consider in the management of diverse ethical issues. In Part 2, the authors delineate proactive steps to facilitate the resolution of administrative problems with economic, social, and ethical dimensions. They apply the model to the problem of the nursing shortage. Although no guarantees are assured in following the steps, decision making may be facilitated during the ethical conflict.

Common-sense ethics in administrative decision making. Part I, Preparatory steps

This is Part 1 of two articles demonstrating the relevance of business ethics to nurse administrators as they confront value-laden issues such as the advantages and disadvantages of 10-12-hour scheduling patterns, understaffing, emerging registered nurse partnerships, and other administrative problems. Common-sense ethics can serve as the basis of just administrative decisions. The authors present a model of preparatory attitudes and behaviors. The steps that they propose do not guarantee success, but if implemented, they may facilitate the nurse administrator's management of diverse ethical issues.

Suppression of chromogranin-A release from neuroendocrine sources in man: pharmacological studies

Chromogranin-A (CgA) is an acidic soluble protein with a virtually ubiquitous occurrence in normal human neuroendocrine tissues. Of the many potential tissue sources of CgA immunoreactivity, which contribute to basal (unstimulated) circulating CgA? To explore this question we studied the effects of selective and nonselective suppression of secretion at several sites within the neuroendocrine system. Selective disruption of sympathetic outflow by trimethaphan decreased basal CgA by 25%, suggesting that sympathetic neurons contribute to circulating CgA. Plasma CgA in patients with unilateral and bilateral adrenalectomy fell within the range observed in normal subjects, weighing against the adrenal medulla as a major source of basal circulating CgA. Selective suppression of a variety of anterior and posterior pituitary cell types decreased plasma levels of the usual resident peptide hormones, but left plasma CgA unperturbed. After propranolol treatment, plasma CgA remained unaltered. Secretin suppressed plasma PTH and calcitonin, but did not alter plasma CgA levels. On the other hand, widespread nonselective suppression of a variety of neuroendocrine secretory cells by somatostatin decreased plasma CgA by 48%. Plasma catecholamines were unaltered by somatostatin infusion, suggesting that somatostatin inhibited CgA release from nonsympathoadrenal sources. During the infusion of somatostatin, the plasma epinephrine increment in response to insulin-induced hypoglycemia was maintained, and plasma CgA did not fall, nor did it rise after somatostatin cessation. Taken together, these findings suggest that somatostatin did not inhibit transport of stimulation-released CgA from the adrenal medulla to the circulation. In conclusion, although the adrenal medulla is the major tissue source of CgA immunoreactivity in man, other neuroendocrine sites, including sympathetic axons and multiple endocrine glands, appear to influence the basal circulating concentration of CgA.

Subcritical flutter in collapsible tube flow: a model of expiratory flow in the trachea

Using an axisymmetric geometry that retains certain qualitative features of the trachea, we extend one-dimensional modeling of flow in collapsible tubes to include both curved shell effects and, for untethered tubes, wall inertia. A systematic scaling of the finite deformation membrane equations leads to an approximate set which is consistent with the one-dimensional fluid model; axial and normal wall variables are coupled elastically, but only axial inertia is retained. Transverse curvature causes elastic coupling that can give rise to axial wall motion and a flutter instability. The source of instability is the product of a nonzero reference axial curvature with axial tension variation due to axial stretching. The numerical results suggest that this mechanism may be significant even in processes which cannot be assumed one-dimensional.

Purification and properties of two lactose hydrolases from Trichosporon cutaneum

Two enzymes that hydrolysed lactose were purified essentially to homogeneity from cell extracts of the oleaginous yeast Trichosporon cutaneum. One enzyme of Mr 120,000 had properties typical of a beta-galactosidase (EC 3.2.1.23). It hydrolysed lactose, lactulose and nitrophenyl-beta-D-galactosides. The enzyme required K+ or Rb+ for activity, and other monovalent cations tested were not effective. Enzyme activity was abolished by EDTA and stimulated by Mg2+, Mn2+ and Ca2+. The beta-galactosidase was induced by lactose, galactose, lactulose and lactobionic acid. The other enzyme, a beta-glycosidase (EC 3.2.1.21) of Mr 52,000 showed no ionic requirements and it hydrolysed lactose, nitrophenyl-beta-D-galactosides, 4-nitrophenyl-beta-D-glucoside, cellobiose, laminaribiose, laminaritriose and sophorose, but not gentiobiose, 4-nitrophenyl-beta-D-mannoside or sucrose. This enzyme was induced by lactose, galactose and lactulose, and also by cellobiose.

Evidence for a role for secreted aspartate proteinase of Candida albicans in vulvovaginal candidiasis

The presence of the secretory aspartate (acid) proteinase in the vaginal fluid of candidal vaginitis patients and controls was studied by ELISA and immunoblot (Western blot). In addition, a proteinase-deficient mutant strain of Candida albicans (IR24) was compared with the wild-type parent strain (10261) for ability to infect the vagina of pseudoestrus rats under estradiol treatment. Among the 67 women examined, proteinase was detected only in 22 harboring C. albicans (range, 42-233 ng/ml of vaginal fluid), at concentrations significantly higher in the 14 vaginitis patients than in the 8 asymptomatic fungal carriers. Western blots confirmed the presence of only one protein band of approximately 43 kDa, corresponding to that of the purified proteinase, in the ELISA-positive vaginal fluids. Experimental vaginal infection was significantly more extensive and persistent in rats infected with the proteinase-producer strain than in those challenged with the proteinase-deficient mutant, and the enzyme was detected in the vaginas of the former but not of the latter animals. Both strains 10261 and IR24 developed hyphal forms to a roughly similar extent during infection, and both showed a comparable adherence in vitro to vaginal and buccal epithelial cells. The clinical and experimental evidence support a role for secretory proteinase as a virulence factor in the pathogenesis of candidal vaginitis.

The secreted aspartate proteinase of Candida albicans: physiology of secretion and virulence of a proteinase-deficient mutant

It was established that Candida albicans grew rapidly in a simple medium containing yeast extract (0.2%, w/v) plus glucose (2%, w/v). These cultures were in or near to a state of nitrogen limitation and the concentration of secreted aspartate proteinase increased rapidly (within 3-4 h) on addition of BSA. Synthesis and secretion were apparently controlled both positively (induction by albumin or, more probably, the peptides produced from it) and negatively (repression by NH4Cl). A small intracellular pool of the enzyme was detected during production of the enzyme and this pool decreased with the cessation of synthesis and secretion. A stable mutant, IR24, was isolated which secreted less than 0.3% of the amount of the proteinase exported by the parent strain ATCC 10261. The LD50 values for mutant IR24 and the parent strain administered intravenously to mice were greater than 1.0 x 10(9) and 1.6 x 10(6) c.f.u. kg-1 respectively.

Is physiologic sympathoadrenal catecholamine release exocytotic in humans?

In cultured cells and isolated perfused organs, catecholamines are coreleased with chromogranin A (CgA) from adrenal chromaffin cells and sympathetic neurons. The corelease suggests that exocytosis is the mechanism of catecholamine secretion. To investigate whether physiologic catecholamine secretion is exocytotic in humans, we measured plasma norepinephrine, epinephrine, and CgA responses to differentiated stimuli of sympathoadrenal discharge. The CgA radioimmunoassay antibody recognized authentic CgA in normal human adrenal chromaffin vesicles. Insulin-induced hypoglycemia and caffeine ingestion, in decreasing order of potency, selectively stimulated epinephrine release from the adrenal medulla. During hypoglycemia, plasma levels of epinephrine and CgA rose, and peak plasma levels of epinephrine and CgA correlated, suggesting that gradations in epinephrine release represented gradations in exocytosis. However, significant increments in plasma CgA were not observed after caffeine ingestion. Furthermore, the rise of CgA levels during hypoglycemia lagged 60 minutes behind those of epinephrine. A less-pronounced temporal dissociation between CgA and epinephrine release was also shown in isolated chromaffin cells in vitro. Selective adrenal vein catheterization suggested a barrier to CgA transport across the adrenal capillary wall. Short-term, high-intensity dynamic exercise, assumption of the upright posture, prolonged low-intensity dynamic exercise, and smoking, in decreasing order of potency, stimulated norepinephrine release from sympathetic nerve endings. Only the first sympathetic neuronal stimulus resulted in significant increments in plasma CgA, increments considerably less than those attained during adrenal medullary activation by insulin hypoglycemia. During high-intensity exercise, peak plasma norepinephrine and CgA levels correlated, suggesting that gradations in norepinephrine release represented gradations in exocytosis. The human adrenal medulla was a far more prominent tissue source of CgA than human sympathetic nerves--adrenal medullary homogenates contained 97-fold more CgA (micrograms/g) than sympathetic nerve homogenates. In conclusion, catecholamine secretion during selective stimulation of either sympathetic nerves or the adrenal medulla is, at least in part, exocytotic. Furthermore, stimulation of the former results in comparatively modest changes in plasma CgA compared with changes attained during stimulation of the latter. CgA appears to be transported by a route different from that of catecholamines from adrenal medullary chromaffin cells to the circulation in vivo.

Policy considerations related to AIDS

The nurse administrator faces many legal obligations as well as administrative responsibilities in the care of patients and staff with AIDS infection or at risk of infection. The authors discuss several resources nurse administrators can use to develop and implement policy for patients and staff at risk for or with AIDS infection.

Strenuous short-term dynamic exercise: effects on heart rate, blood pressure, potassium homeostasis, and packed cell volume in mild hypertension

This study examined the effect of strenuous short-term dynamic exercise on the heart rate, blood pressure, plasma potassium and packed cell volume in mildly hypertensive subjects. At baseline a symptom-limited Bruce Exercise Protocol was carried out with blood pressure, heart rate, plasma potassium and packed cell volume measurements at fixed time points at rest and during and after the exercise. After 6 weeks of taking exercise sessions (Bruce protocol) to fatigue three times a week, the subjects were restudied. Blood pressure and the heart rate fell significantly at rest and during and after exercise. The packed cell volume was higher at all study points and plasma potassium was higher in the postexercise period after the exercise conditioning. Strenuous short-term exercise has a beneficial antihypertensive effect, raises packed cell volume and has a favourable effect on plasma potassium homeostasis.

Unlicensed persons in patient care settings. Administrative, policy, and ethical issues

The current nursing shortage is a supply-and-demand problem. Factors contributing to the shortage include increased hospital use of RNs; decreased nursing school enrollment; increased demand for RNs outside of hospitals in skilled nursing facilities, health maintenance organizations, and home health care programs; noncompetitive salaries; and lack of autonomy. The nursing shortage has triggered the development and implementation of programs to prepare non-nurse bedside technicians to work in partnership with RNs. The functions of these unlicensed persons range from housekeeping, stocking, and clerical responsibilities to several technical treatments that once fell within the role responsibilities of registered or practical nurses. The partnerships between unlicensed persons and RNs in patient care settings have given rise to several administrative, policy, and ethical issues for nurse leaders. An ethical analysis, based on the application of ethical principles and moral dilemmas found in "The Parable of the Sadhu," offers some guidelines to nursing leaders in the administrative and policy decisions inherent in the development and retention of licensed persons in patient care settings. Some conclusions drawn from the ethically based questions are: The acquisition and retention of RNs and other licensed caregivers should take precedence over the development of programs for non-nurse bedside technicians. RNs in partnership with unlicensed persons in patient care settings must know what they can legitimately delegate. The RN has personal responsibility for ensuring optimal standards of nursing practice in the delegation of duties. The partnership between professional nurses and unlicensed persons must be a participative effort, not a manipulative or coercive one. In putting the organizational principle of subsidiarity into practice, decision makers will be able to maintain respect for human dignity and the uniqueness of patients and caregivers as well. The development and retention of unlicensed persons in patient care settings depends on a well-developed personal ethic that needs to be congruent with the mission, philosophy, and codes of ethics of national and local health care organizations.

Fosenopril, an angiotensin-converting enzyme inhibitor, and propranolol: comparative effects at rest and exercise on blood pressure, hormonal variables, and plasma potassium in essential hypertension

Fosenopril sodium, a prodrug, is converted to its active diacid during and after intestinal absorption. Its excretion is equally divided between hepatic and renal routes. This placebo-controlled, randomized, double-blind, parallel group study evaluated the efficacy and safety of fosenopril compared to propranolol, at rest and during exercise, on blood pressure, plasma potassium, plasma renin activity, and plasma aldosterone. Exercise testing utilized bicycle ergometry, and individual subjects underwent an identical exercise protocol on placebo and on active treatment. The fosenopril group comprised nine subjects who were matched to nine subjects on propranolol. Blood pressure fell significantly and equally at rest (fosenopril--157/103 to 141/95 mmHg, p less than 0.005; propranolol--159/100 to 149/90 mmHg p less than 0.005) and during exercise in both groups. Plasma potassium fell significantly at rest (4.25 to 3.98 mmol/l, p less than 0.05) and during exercise (5.18 to 4.87 mmol/l, p less than 0.05) on fosenopril, but rose in subjects on propranolol during exercise (4.99 to 5.44 mmol/l, p less than 0.01). Plasma renin activity rose on fosenopril and fell on propranolol. Plasma aldosterone was uninfluenced by either drug. Fosenopril was well tolerated and its antihypertensive profile is similar to that of beta blockers and other ACE inhibitors.

Alterations in maternal plasma corticosterone levels following treatment with phenytoin

The mechanisms of the embryotoxic effects of the anticonvulsant drug, phenytoin (PHT), are unknown. Glucocorticoids and PHT demonstrate similar embryopathic effects and strain sensitivity in that A/J mice are very sensitive to the embryopathic effects of synthetic glucocorticoids and PHT while C57BL/6 (B6) mice are comparatively resistant to both. It is possible that teratogenic consequences of PHT are not a result of drug interaction at the target site but are mediated indirectly by glucocorticoids. In this study, PHT was administered by intraperitoneal injection at 25 (a nonteratogenic dose) or 75 mg/kg body weight (a teratogenic dose) to pregnant A/J mice on Day 10 of gestation. Mice of the B6 strain received the drug at 75 mg/kg on Day 10. Control mice received vehicle (pH 11.0 distilled water). Dams were killed at various times after the injection; plasma samples were obtained, and corticosterone levels were determined by radioimmunoassay. In control animals, maternal plasma corticosterone levels were elevated soon after dosing but gradually declined, except for an apparent circadian rhythm effect seen in samples obtained in the afternoon. Administration of a nonteratogenic dose of PHT to A/J mice caused a temporary increase in plasma corticosterone levels which decreased to the control level between 6 and 24 hr following dosing. Treatment with a teratogenic dose in A/J mice led to plasma levels that remained elevated for the entire 48-hr period examined in this study. In B6 mice, treatment with 75 mg/kg increased plasma corticosterone levels for 24 hr, after which they declined to the control value by 30 hr. The adrenal corticosteroid response of A/J mice to PHT appeared to be much more sensitive than that of B6 mice, and there appeared to be a relationship between plasma levels of PHT and corticosterone. The lengthy increase in plasma corticosterone during organogenesis may be a factor in the increased incidence of cleft lip and palate seen after administration of PHT to A/J mice.

Effects of fosenopril, a once-daily angiotensin-converting enzyme inhibitor, on resting and exercise-induced changes of blood pressure, hormonal variables, and plasma potassium in essential hypertension

Fosenopril, a new angiotensin-converting enzyme (ACE) inhibitor, is a prodrug that is converted to its active diacid metabolite after intestinal absorption. Its excretion is equally divided between hepatic and renal routes. This study details the efficacy of fosenopril at rest and during exercise on blood pressure, plasma potassium, plasma renin activity, and plasma aldosterone in 11 hypertensive males, mean age 55 years. Individual subjects underwent an identical exercise protocol (bicycle ergometry) on placebo and on active treatment. Supine mean blood pressure fell from 116 to 100 mm Hg, P less than 0.005, and at 9 minutes of exercise mean blood pressure fell from 137 to 125 mm Hg, P less than 0.01 on fosenopril. Plasma potassium fell slightly at rest from 4.27 to 3.96 mmol/L and during exercise from 5.23 to 4.93 mmol/L, both P less than 0.025. Plasma renin activity (ng/mL/hr) rose on fosenopril, at rest 0.94 to 4.72, and during exercise 2.06 to 10.39, both P less than 0.005. Aldosterone changes on treatment were marginal and nonsignificant. The compound was well tolerated and free of subjective and routine laboratory side effects. Its antihypertensive action is broadly similar to the other ACE inhibitors currently available.

The cellular location of proteases in Candida albicans

Vacuoles prepared from yeast cells of Candida albicans were enriched in proteinase ycaB (EC 3.4.21.48) but not in aminopeptidase or beta-glucosidase. Proteinase ycaB, assayed in situ, increased 1.5-fold during starvation whereas aminopeptidase activity decreased by 25%. Proteinase ycaB increased a further 1.5-fold during germ-tube formation.

Effects of clonidine on central and peripheral nerve tone in primary hypertension

To define the mechanisms whereby clonidine lowers blood pressure, we measured cerebrospinal fluid and plasma levels of norepinephrine, normetanephrine, epinephrine, dopamine, and the dopamine metabolite homovanillic acid in 10 primary hypertensive subjects before and after 3 months of clonidine treatment (mean dose, 0.68 mg/day). Catecholamines were measured by radioenzymatic methods. Cerebrospinal fluid and plasma sampling was performed after subjects had fasted and remained supine overnight, and plasma sampling was repeated 2 hours later, after subjects had ambulated. Supine and upright blood pressure fell, as might be expected. Cerebrospinal fluid levels of norepinephrine and normetanephrine fell significantly, but dopamine and homovanillic acid levels were unchanged. Plasma norepinephrine, normetanephrine, and epinephrine levels decreased 30 to 50%, and supine dopamine levels also fell. The percent fall in supine blood pressure was related to the fall of cerebrospinal fluid and plasma norepinephrine. There were also positive relationships between the decreases of plasma norepinephrine and of normetanephrine and dopamine. The cerebrospinal fluid/plasma norepinephrine ratio was unaffected by clonidine, suggesting that the drug lowered both pools equally. Our findings indicate that clonidine decreases both central and peripheral norepinephrine activity. The dopaminergic activity of cerebrospinal fluid was unaffected by clonidine, and though plasma dopamine levels tended to be lower after treatment, mean plasma prolactin level, an index of dopaminergic activity, was also unchanged. The fall in plasma epinephrine level is probably related to diminished sympathetic adrenomedullary stimulation and is unlikely to contribute to clonidine's antihypertensive action. These results also suggest that measurement of normetanephrine in cerebrospinal fluid and plasma provides a good index of norepinephrine activity.

The purification and properties of yeast proteinase B from Candida albicans

A serine proteinase (ycaB) from the yeast Candida albicans A.T.C.C. 10261 was purified to near homogeneity. The enzyme was almost indistinguishable from yeast proteinase B (EC 3.4.21.48), and an Mr of 30,000 for the proteinase was determined by SDS/polyacrylamide-gel electrophoresis. The initial site of hydrolysis of the oxidized B-chain of insulin, by the purified proteinase, was the Leu-Tyr peptide bond. The preferential degradation at this site, analysed further with N-blocked amino acid ester and amide substrates, demonstrated that the specificity of the proteinase is determined by an extended substrate-binding site, consisting of at least three subsites (S1, S2 and S'1). The best p-nitrophenyl ester substrates were benzyloxycarbonyl-Tyr p-nitrophenyl ester (kcat./Km 3,536,000 M-1 X S-1), benzyloxycarbonyl-Leu p-nitrophenyl ester (kcat./Km 2,250,000 M-1 X S-1) and benzyloxycarbonyl-Phe p-nitrophenyl ester (kcat./Km 1,000,000 M-1 X S-1) consistent with a preference for aliphatic or aromatic amino acids at subsite S1. The specificity for benzyloxycarbonyl-Tyr p-nitrophenyl ester probably reflects the binding of the p-nitrophenyl group in subsite S'1. The presence of S2 was demonstrated by comparison of the proteolytic coefficients (kcat./Km) for benzyloxycarbonyl-Ala p-nitrophenyl ester (825,000 M-1 X S-1) and t-butyloxycarbonyl-Ala p-nitrophenyl ester (333,000 M-1 X S-1). Cell-free extracts contain a heat-stable inhibitor of the proteinase.

The isolation of plasma membrane and characterisation of the plasma membrane ATPase from the yeast Candida albicans

Plasma membrane ghosts were isolated from Candida albicans ATCC 10261 yeast cells following stabilisation of spheroplasts with concanavalin A, osmotic lysis and Percoll density gradient centrifugation. Removal of extrinsic proteins with NaCl and methyl alpha-mannoside gave increased ATPase and chitin synthase specific activities in the resultant plasma membrane fraction. Sonication of this fraction yielded unilamellar plasma membrane vesicles which exhibited ATPase and chitin synthase specific activities of 4.5-fold and 3.0-fold, respectively, over those of the plasma membrane ghosts. ATPase activity in the membrane ghosts was optimal at pH 6.4, showed high substrate specificity (for Mg X ATP) and was inhibited 80% by sodium vanadate but less than 4% by oligomycin and azide. The effects of a range of other inhibitors were also characterised. Temperature effects of ATPase activity were marked, with a maximum at 35 degrees C. Breaks in the Arrhenius plot, at 12.2 degrees C and 28.9 degrees C, coincided with endothermic heat flow peaks detected by differential scanning calorimetry. ATPase was solubilised from the plasma membranes with Zwittergent in the presence of glycerol and phenylmethylsulphonyl fluoride and partially purified by glycerol density gradient centrifugation. The solubilised enzyme hydrolysed Mg X ATP at Vmax = 20 mumol X min-1 X mg-1 in the presence of phospholipids, with optimal activity at pH 6.0--6.5.

A Candida albicans mutant impaired in the utilization of N-acetylglucosamine

Indicator plates containing eosin, methylene blue, glucosamine and proline were used to select mutants of Candida albicans impaired in the utilization of glucosamine. One such mutant, strain hOG298, grew on glucosamine at a slower rate than the parent and was severely impaired in growth on N-acetylglucosamine. The mutant was unable to express the first three steps in the N-acetylglucosamine pathway: viz the permease, N-acetylglucosamine kinase and N-acetylglucosamine-6-phosphate deacetylase. Glucosamine-6-phosphate deaminase was, however, induced by N-acetylglucosamine. The mutant still possessed a constitutive uptake system and kinase activity for glucosamine but glucosamine neither increased the glucosamine kinase activity nor induced N-acetylglucosamine kinase. These findings accounted for the decreased growth rate on glucosamine. The parent strain formed germ-tubes in N-acetylglucosamine or 4% (v/v) serum but the mutant formed germ-tubes only in serum.

Diabetic control and the renin-angiotensin system, catecholamines, and blood pressure

Diabetic ketoacidosis is usually associated with marked secondary hyperaldosteronism. Plasma levels of renin, angiotensin II, and aldosterone are markedly raised before treatment in most patients, with values falling rapidly toward normal as metabolic control is restored. In a few patients, mostly those with long-term complications of diabetes, plasma levels of renin, angiotensin II, and aldosterone before treatment remain within the normal range. In moderately hyperglycemic patients who have glycosuria but not ketonuria, plasma levels of all three substances are significantly higher than when control is improved. Occasionally, moderately hyperglycemic patients have mild secondary hyperaldosteronism. Improved metabolic control in such patients causes a rise in plasma volume and a rise in total exchangeable sodium, the latter to levels significantly above normal. Plasma catecholamine levels are markedly elevated in diabetic ketoacidosis, probably as a consequence of the ketoacidotic state. In nonketotic patients with moderate hyperglycemia, basal plasma norepinephrine levels are normal; catecholamine responses to exercise may be exaggerated, however. Epidemiological and animal studies suggest a relationship between blood pressure and blood glucose levels. There are few clinical studies of the effects of altering metabolic control of diabetes on blood pressure, and this is an important area for further study.