Endothelial function in hypertension

Endothelial dysfunction has been documented both in the forearm and coronary beds of essential hypertensive patients. Impairment in the tonic release of nitric oxide (NO) is secondary to hypertension, while the alteration in agonist-induced endothelium-dependent vasodilation seems to be a primary defect caused both by an alteration of the L-arginine-NO pathway and the production of cyclooxygenase-dependent EDCFs, such as prostanoids or superoxide anions. These latter substances curtail endothelium-dependent vasodilation mainly by inactivating NO production. Although experimental data clearly indicate that the L-arginine-NO pathway participates in the regulation of renal hemodynamics and renal excretory function under basal and stimulated conditions, data in humans are scanty and confounded by methodological approaches. A posteriori interpretation of data obtained with intrarenal infusion of acetylcholine in kidney donors suggests that endothelium dependent vasodilation in the kidney is impaired by aging, a phenomenon well documented in the forearm and coronary circulation. Systemic infusion of L-arginine induced renal vasodilation and natriuresis in normotensive subjects, an effect which seems to be mediated mainly by intrarenal NO production. Moreover the few available data suggest that both renal vasodilation and renal production of NO in response to L-arginine are blunted in patients with essential hypertension and that superoxide anions, may be, at least partially, responsible for this alteration of the L-arginine-NO pathway. In conclusion, endothelial dysfunction has been well documented in the forearm and coronary circulation of patients with essential hypertension. Available data suggest that endothelial, dysfunction is also detectable in the kidney and that a common mechanism, probably superoxide anions, can account for this abnormality.

Steroid withdrawal in tacrolimus (FK506)-treated pediatric liver transplant recipients

PURPOSE

The use of steroids in pediatric transplant recipients is associated with significant adverse side effects. The authors examined the feasibility of steroid withdrawal in patients who underwent immunosuppression with tacrolimus (FK506; FK).

METHODS

All pediatric liver transplant recipients on FK greater than 6 months were evaluated for steroid withdrawal. FK was administered 0.3 mg/kg/d in two divided doses. Steroids were tapered as tolerated with goals of 0.2 to 0.3 mg/kg/d at 6 weeks, 0.2 to 0.3 mg/kg every other day at 3 months, and complete withdrawal after 6 months. Steroid bolus and taper were instituted for enzyme elevation or rejection during biopsy.

RESULTS

Twenty-nine patients underwent evaluation for steroid withdrawal. Five patients could not be placed on FK506 monotherapy (chronic, recurrent rejection or LPD). The remaining 24 had steroids withdrawn. Tweleve (50%) had no sequelae and continue on FK monotherapy (mean, 22 months off steroids). The other 12 required intermittent steroid therapy for presumed or biopsy-proven rejection (n = 7), graft dysfunction (FK toxicity, n = 2), lymphoproliferative disease necessitating reduction in FK (n = 2) or exacerbations of asthma (n = 1). Five of these 12 patients are now on FK monotherapy (mean, 6 months) for a total of 17 of the 24 (71%) currently off steroids.

CONCLUSION

FK monotherapy can be successfully used to withdraw steroid therapy in the majority of pediatric liver transplant recipients with few sequelae.

Transcapillary escape rate of albumin in type II diabetic patients. The relationship with microalbuminuria and hypertension

OBJECTIVE

To study why in type II diabetes, microalbuminuria, a marker of generalized vascular dysfunction, and hypertension have been linked with both renal and cardiovascular organ damage.

RESEARCH DESIGN AND METHODS

To investigate the effect of moderately elevated blood pressure on vascular damage, the transcapillary escape rate of albumin (TERalb) was measured by intravenous injection of purified 125I-human serum albumin in 9 healthy control subjects (group 1), 9 nondiabetic hypertensive subjects (group 2), and 73 nonobese type II diabetic patients stratified as follows: group 3: 17 normoalbuminuric-normotensive subjects; group 4: 22 normoalbuminuric-hypertensive subjects (systolic blood pressure [sBP] > or = 140 mmHg or diastolic blood pressure [dBP] > or = mmHg or both); group 5: 16 normotensive subjects with microalbuminuria (albumin excretion rate [AER]: 20-200 micrograms/min); and group 6: 18 microalbuminuric-hypertensive subjects.

RESULTS

Groups 3-6 had similar age, sex, duration of diabetes (group 3: 7.8 +/- 5.5; group 4: 9.7 +/- 8.7; group 5: 12.1 +/- 8.1; and group 6: 10.7 +/- 8.3 years), BMI, HbA1c (7.8 +/- 1.1, 7.5 +/- 1.5, 8.7 +/- 1.5, and 7.7 +/- 1.1%, respectively), blood glucose, and lipid profile. Systolic and diastolic blood pressure did not differ in the three hypertensive group (group 2: 154 +/- 3/99 +/- 6; group 4: 149 +/- 13/95 +/- 6; group 6: 154 +/- 15/91 +/- 9 mmHg) and were significantly lower (P < 0.001) in group 3 (126 +/- 12/76 +/- 7), group 5 (128 +/- 11/77 +/- 5), and healthy control subjects (group 1: 133 +/- 7/81 +/- 4). TERalb was similar in control subjects (5.77 +/- 1.06%/h) and in normoalbuminuric-normotensive subjects (5.81 +/- 1.51%/h) but significantly higher (P < 0.0001) in microalbuminuric subjects with or without hypertension (9.11 +/- 1.65 and 8.60 +/- 1.50%/h, respectively) as well as in normoalbuminuric diabetic patients with hypertension (8.10 +/- 2.27%/h) and in essential hypertensive subjects (8.12 +/- 1.68%/h).

CONCLUSIONS

By stepwise regression, TERalb was related (step 1) to log-AER (r = 0.30) or to the presence of microalbuminuria (r = 0.36) and (step 2) to dBP (multiple r = 0.40) or to the presence of hypertension (multiple r = 0.51) in the whole diabetic cohort (groups 3-6). TERalb was related to dBP (r = 0.47) or to the presence of hypertension (r = 0.56) only in normoalbuminuric diabetic patients (groups 3 and 4) and to log-AER (r = 0.56) or the presence of microalbuminuria (r = 0.68) only in normotensive patients (groups 3 and 5). In type II diabetic patients, TERalb was elevated in subjects with increased albuminuria, irrespective of blood pressure levels, but also was independently related to the presence of mild-to-moderate systemic hypertension.

Wisconsin card sorting test and Stroop test performance in schizophrenia: a shared construct

The Wisconsin card sorting test (WCST) and Stroop test were administered to 25 schizophrenic patients in order to better identify and understand more specific processing mechanisms involved in executive dysfunctions and to investigate their hypothetical involvement in symptom formation. Data show that for as much as the two tests employed measured executive functions in terms of mental control and cognitive flexibility, our findings seemed to indicate shared or interconnected mechanisms. No correlations were seen between the psychopathological evaluation and any of the neuropsychological indexes. The use of the Stroop task could provide a more readily cognitive analysis in terms of specific processing mechanisms, at the basis of WCST impairment in schizophrenia.

Remediation of Wisconsin Card Sorting Test performance in schizophrenia. A controlled study

Previous studies have shown encouraging plasticity in some schizophrenic patients' Wisconsin Card Sorting Test (WCST) performance while receiving detailed specific instructions on task and reinforcement. The present study examines the efficacy of a modified procedure for WCST administration that bound schizophrenic patients to use a conceptually driven cognitive strategy without instruction or reinforcement. The schizophrenics' results were also compared to those obtained with the same procedure from a matched control sample. By using this procedure, 63.2% of WCST schizophrenic poor performers dramatically improved their results. Schizophrenic poor performers who did not achieve remediation were of a younger age at onset and had more negative symptoms. This pattern was strictly associated with more perseverative errors on WCST that increased even more when the conceptually driven processing was forced. Our findings could have important implications for our understanding of the underlying cognitive deficit of the poor neuropsychological performance and allow the distinction of schizophrenic subtypes who show peculiar features that probably reflect a different pathophysiology and would potentially benefit from different modalities of treatment and rehabilitation.

Hypertension causes premature aging of endothelial function in humans

We designed the present study to evaluate whether in normotensive subjects and hypertensive patients aging causes endothelial dysfunction by a defect in the L-arginine-nitric oxide pathway or production of cyclooxygenase-dependent vasoconstrictors. In 43 normotensive subjects and 47 essential hypertensive patients, we evaluated forearm blood flow (strain-gauge plethysmography) modifications evoked by intrabrachial acetylcholine (0.15, 0.45, 1.5, 4.5, and 15 microg/100 mL per minute), an endothelium-dependent vasodilator, in the presence of saline, L-arginine (1 micromol/100 mL per minute), or indomethacin (50 microg/100 mL per minute), a cyclooxygenase inhibitor, and by sodium nitroprusside (1, 2, and 4 microg/100 mL per minute), an endothelium-independent vasodilator. Vasodilation to acetylcholine was lower (P<.01) in essential hypertensive patients than normotensive control subjects, and in both groups, it declined with advancing age. In normotensive subjects older than 30 years, L-arginine potentiated the response to acetylcholine in parallel with increasing age, whereas indomethacin increased the vasodilation to acetylcholine only in the oldest group (>60 years). In younger hypertensive patients (<30 years), L-arginine but not indomethacin potentiated the response to acetylcholine. In adult patients (31 to 45 years), L-arginine still potentiated the vasodilation to acetylcholine, and indomethacin began to show some effect. In the oldest patients (46 to 60 and >60 years), L-arginine was no longer effective, and indomethacin exerted a potentiating action that was positively related to advancing age. In normotensive and hypertensive humans, similar mechanisms, including dysfunction of the nitric oxide pathway and production of cyclooxygenase-dependent vasoconstrictors, cause age-related impairment of endothelium-dependent vasodilation, and only their earlier appearance characterizes hypertensive disease. Thus, the endothelial dysfunction that occurs in hypertension seems to represent an accelerated form of dysfunction that occurs in aging.

Risperidone, negative symptoms and cognitive deficit in schizophrenia: an open study

The aim of this study was to evaluate the effects of a new antipsychotic compound on negative symptoms and cognitive deficit in schizophrenia. Psychiatric symptoms and cognition were assessed in 25 patients with schizophrenia, at baseline and after they had taken risperidone for 4 weeks. The Positive and Negative Symptoms Scale (PANSS), the Wisconsin Card Sorting Test (WCST) and two WAIS sub-tests were used to assess the patients. After the study period, both negative and positive symptoms and also measures of cognitive performance improved significantly. The WCST results correlated with negative symptom scores before and after treatment. This suggests that negative symptoms and cognitive deficit have a common underlying substrate which is the target of the risperidone treatment. Our data show that risperidone may have a substantial effect on complex cognitive functions in schizophrenia, and they suggest that certain cognitive deficits are relatively dependent on the negative symptoms of this disorder.

Menopause is associated with endothelial dysfunction in women

To evaluate the effect of endogenous estrogens on endothelial function in humans, we examined whether menopause is associated with impairment in endothelium-dependent vasodilation in normotensive and essential hypertensive women. In 73 normotensive subjects (37 women, 36 men) and 73 hypertensive patients (36 women, 37 men), we studied endothelial function by measuring forearm blood flow modifications (strain-gauge plethysmography) induced by intrabrachial acetylcholine (0.15, 0.45, 1.5, 4.5, and 15 micrograms/100 mL per minute), an endothelium-dependent vasodilator, and sodium nitroprusside (1,2, and 4 micrograms/100 mL per minute), an endothelium-independent vasodilator. Women younger than 45 years had normal menstrual cycles. In essential hypertensive patients, responses to acetylcholine but not to sodium nitroprusside were significantly (P < .001) reduced compared with responses in normotensive subjects. Moreover, in both groups, vasodilation to acetylcholine showed a marked negative correlation with advancing age (normotensive subjects: r = -.88, P < .001; hypertensive patients: r = -.87, P < .001). In contrast, vasodilation to sodium nitroprusside showed a less evident negative correlation with advancing age (normotensive subjects: r = -46, P < .01; hypertensive patients: r = -.48, P < .01). However, in normally menstruating normotensive women, no endothelial dysfunction was observed, and age-related impairment in endothelium-dependent vasodilation was evident only after menopause. In normally menstruating hypertensive women, aging was associated with endothelial dysfunction although the deterioration of endothelium-dependent vasodilation was less marked than that in men. In contrast, after menopause, the age-related endothelial dysfunction in hypertensive women was similar to that observed in men. Finally, no sex-related difference in the response to sodium nitroprusside was observed in either normotensive subjects or essential hypertensive patients. Age-related endothelial dysfunction is attenuated in premenopausal normotensive and hypertensive women compared with men, whereas no sex-induced difference is observed after menopause, suggesting a protective effect of endogenous estrogens on endothelial function.

Cardiovascular characteristics in normotensive subjects with or without family history of hypertension

The aim of our study was to evaluate whether initial changes of cardiovascular structure and/or function can be detected in young normotensive subjects with (F+) and without (F-) family history of hypertension. Thirty-two subjects (19 F+, 10 males and 9 females, age range 17-32 years; 13 F-, 6 males and 7 females, age range 19-33 years) were studied. In each subject 24 hours ambulatory blood pressure monitoring, a M-mode, 2d guided and pulsed doppler echocardiogram and postischemic forearm strain gauge plethysmography were performed. The two groups of subjects did not differ for causal systolic and diastolic BP and 24 hours systolic and diastolic ambulatory monitored blood pressure. No differences in LV end-diastolic and end-systolic diameters, as well as in LV wall thickness, and in LV mass index were observed. Systolic functional parameters were also similar in the two groups. In F+ subjects peak early filling velocity was reduced in respect to F- (p < 0.01), peak late filling velocity integral was increased (p < 0.05) and the ratio of peak E/peak A integrals was decreased (p < 0.05). No difference was observed for postischemic forearm blood flow and minimal vascular resistance, taken as an index of arteriolar structural changes as well as intima-media thickness of carotid arteries. In conclusion in this study F+ and F- had similar BP values, LV mass and min VR; differences previously observed in LV mass between F+ and F- may have been due to the presence of different basal levels of BP; in F+ LV diastolic filling, although still in the normal range, shifted early toward the pattern of LV filling usually observed in hypertensive patients.

Defective L-arginine-nitric oxide pathway in offspring of essential hypertensive patients

BACKGROUND

Essential hypertension is characterized by impaired endothelium-dependent vasodilation. The present study was designed to investigate whether this abnormality is a primary defect or a consequence of blood pressure increases.

METHODS AND RESULTS

In offspring of essential hypertensive patients (n = 34) and normotensive subjects (n = 30), we evaluated forearm blood flow (strain-gauge plethysmography) modifications induced by intrabrachial acetylcholine (0.15, 0.45, 1.5, 4.5, and 15 micrograms.100 mL-1.min-1), an endothelium-dependent vasodilator, and sodium nitroprusside (1, 2, and 4 micrograms.100 mL-1.min-1), an endothelium-independent vasodilator. Minimal forearm vascular resistances also were calculated as the ratio between mean intra-arterial pressure and maximal forearm blood flow induced by forearm ischemia and hand exercise. Vasodilation to acetylcholine was significantly (P < .01) blunted in offspring of hypertensive patients compared with offspring of normotensive subjects, whereas the responses to sodium nitroprusside and minimal forearm vascular resistances were similar. In two subgroups of 14 offspring of essential hypertensive patients but not in 10 offspring of normotensive subjects, vasodilation to acetylcholine was increased by intra-brachial L-arginine (1 mumol.100 mL-1.min-1), the substrate for nitric oxide synthesis, whereas in the other 10 and 8 offspring of essential hypertensive patients and normotensive subjects, respectively, cyclooxygenase blockade by intra-brachial indomethacin (50 micrograms.100 mL-1.min-1) was ineffective.

CONCLUSIONS

Offspring of essential hypertensive patients are characterized by a reduced response to acetylcholine linked to a defect in the nitric oxide pathway, suggesting that an impairment in nitric oxide production precedes the onset of essential hypertension.

Effect of insulin on acetylcholine-induced vasodilation in normotensive subjects and patients with essential hypertension

BACKGROUND

The present study was designed to directly test the vasodilation action of insulin and its relation to endothelium-dependent mechanisms.

METHODS AND RESULTS

In 18 normotensive subjects and 27 patients with untreated mild to moderate essential hypertension, we studied the effect of intrabrachial insulin on the changes in forearm blood flow (strain-gauge plethysmography) induced by intrabrachial acetylcholine (at doses of 0.15, 0.45, 1.5, 4.5, and 15 micrograms.min-1.dL-1), an endothelium-dependent vasodilator, or sodium nitroprusside (at doses of 1, 2, and 4 micrograms.min-1.dL-1), and endothelium-independent vasodilator. Local hyperinsulinemia (deep venous plasma insulin, 48 +/- 6 and 51 +/- 5 microU/mL in control subjects and hypertensive patients, respectively) did not affect basal forearm blood flow and stimulated forearm glucose extraction (control subjects, 3 +/- 1% to 11 +/- 2%, P < .001; hypertensive patients, 3 +/- 1% to 6 +/- 1%, P < .001; P < .01 for the between-group difference). In both normotensive and hypertensive subjects, insulin significantly potentiated acetylcholine-induced vasodilation, whereas it did not alter the vasodilatory response to sodium nitroprusside. NG-monomethyl-L-arginine, an inhibitor of endothelial nitric oxide synthesis, blunted insulin-induced facilitation of acetylcholine vasodilation in normotensive but not in hypertensive subjects. In contrast, in hypertensive patients but not in normotensive control subjects, the potentiation of the vascular response to acetylcholine induced by local hyperinsulinemia was abolished by intrabrachial ouabain, an inhibitor of Na(+)-K+ pump.

CONCLUSIONS

In healthy humans and essential hypertensive patients alike, local physiological hyperinsulinemia per se does not increase forearm blood flow but potentiates the vasodilation induced by acetylcholine regardless of metabolic insulin resistance. This effect is endothelium-dependent because it is not seen with nitroprusside and is related to the L-arginine-nitric oxide pathway in normotensive subjects and to smooth muscle cell hyperpolarization in essential hypertensive patients.

Lack of correlation between microalbuminuria and endothelial function in essential hypertensive patients

OBJECTIVE

To evaluate whether microalbuminuria, defined as urinary albumin excretion between 30 and 300 mg/24 h, is associated with endothelial dysfunction in essential hypertensive patients.

DESIGN

We correlated urinary albumin excretion with vasodilatation in response to endothelium-dependent (acetylcholine) and -independent (sodium nitroprusside) agonists in the forearm vascular bed in essential hypertensive patients with (n = 13) and without (n = 23) microalbuminuria and matched normotensive controls (n = 21).

METHOD

We studied forearm vascular responses (strain-gauge plethysmography) to intrabrachial infusion of acetylcholine (0.15, 0.45, 1.5, 4.5 and 15 ng/100 ml forearm tissue/min) and of sodium nitroprusside (1, 2, 4ng/100 ml forearm tissue per min). Minimal forearm vascular resistances (the ratio between mean arterial pressure and maximal forearm vasodilation induced by 13 min of ischaemia + 1 min of exercise) were also evaluated.

RESULTS

Responses to acetylcholine, but not to sodium nitroprusside, were significantly blunted and minimal forearm vascular resistances were increased in hypertensive patients compared with controls. However, no correlation was found between urinary albumin excretion and vasodilatation in response to acetylcholine or to sodium nitroprusside or between urinary albumin excretion and minimal forearm vascular resistances.

CONCLUSIONS

In hypertensive patients, increased urinary albumin excretion is associated neither with functional nor with structural dysfunction in the forearm vasculature.

Humoral and haemodynamic effects of idrapril calcium, the prototype of a new class of ACE-inhibitors, in essential hypertensive patients

Idrapril is the prototype of a new class of ACE inhibitors, characterised by the presence of a hydroxdmic group. Six untreated in-patients with essential hypertension were given single oral doses of the calcium salt of idrapril, idrapril calcium (200 mg) and placebo according to a double blind, randomised experimental design. Supine and upright blood pressure, heart rate, plasma idrapril serum UCE, active renin and angiotensin II were measured at timed intervals for 24 hours after dosing. Plasma idrapril reached a peak after 2 hours (3.01 microgm x ml(-1)), and by 12 hours the compound had almost disappeared (67 ng x ml(-1)). Derived t1/2 was 1.4-2.2 h. ACE activity was suppressed [from 77.9 to 3.3 after 2 hours and 11.8 after 12 hours nmol(-1) x min(-1) x ml] and angiotensin II production inhibited [from 8.8 to 3.1 (after 1 hour) and 7.5 (after 24 hours) pg x ml(-1)]. Compared to placebo, idrapril calcium significantly lowered both supine blood pressure starting at 4 hours (idrapril calcium 140/93 mmHg; placebo 157/101 mmHg; placebo 147/100 mmHg), and upright blood pressure starting at 3 hours (idrapril calcium 135/95 mmHg; placebo 147/100 mmHg) up to 24 hours (idrapril calcium 132/92 mmHg; placebo 145/100 mmHg). Idrapril calcium appears to be an effective ACE inhibitor in essential hypertension, with a hypotensive action for up to 24 h.

Angiotensin II and sympathetic activity in sodium-restricted essential hypertension

Angiotensin II (Ang II) potentiates sympathetic neurotransmission by presynaptic facilitation of norepinephrine release. We investigated whether endogenous Ang II modulates peripheral sympathetic activity in sodium-depleted essential hypertensive patients. We evaluated the effect of intrabrachial infusion of saralasin, an Ang II antagonist (5 micrograms/100 mL forearm tissue per minute), and benazeprilat, an angiotensin-converting enzyme inhibitor (2 micrograms/100 mL forearm tissue per minute), on forearm vasoconstriction (measured by strain-gauge venous plethysmography) induced by the application of lower body negative pressure (-10 mm Hg for 5 minutes). Both saralasin and benazeprilat (n = 6 for each group) blunted the vasoconstrictor action of lower body negative pressure, suggesting that circulating Ang II modulates peripheral sympathetic activity. In addition, since beta-adrenoceptor stimulation can activate the production of vascular Ang II, the effect of saralasin and benazeprilat on lower body negative pressure application was evaluated in the presence of isoproterenol (0.09 microgram/100 mL forearm tissue per minute) and propranolol (10 micrograms/100 mL forearm tissue per minute). In two other groups of hypertensive patients, isoproterenol infusion increased the release of Ang II in the forearm vasculature (arteriovenous values measured by radioimmunoassay). Furthermore, isoproterenol potentiated lower body negative pressure-induced vasoconstriction. This facilitating effect was abolished by either saralasin or benazeprilat (n = 6 for each group). In contrast, in two further groups of patients (n = 6 for each group), in the presence of the beta-blocker propranolol saralasin and benazeprilat did not alter the vasoconstrictor action of the endogenous sympathetic stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging and endothelial function in normotensive subjects and patients with essential hypertension

BACKGROUND

Experimental data from normotensive and hypertensive animals indicate that aging is associated with impaired endothelium-dependent relaxations to acetylcholine, and this possibility appears to be confirmed in the human coronary artery. In the present study, we evaluated the effect of age on endothelial responsiveness in the forearm vessels of either normotensive control subjects or essential hypertensive patients.

METHODS AND RESULTS

Within the normotensive or hypertensive group (n = 53 and n = 57, respectively), subjects were selected with similar blood pressure, plasma cholesterol, and glucose values, and hypercholesterolemic subjects, diabetics, and smokers were excluded. We evaluated forearm blood flow (by strain-gauge plethysmography) modifications induced by intrabrachial acetylcholine (0.15, 0.45, 1.5, 4.5, and 15 micrograms/100 mL per minute), an endothelium-dependent vasodilator, and sodium nitroprusside (1, 2, and 4 micrograms/100 mL per minute), an endothelium-independent vasodilator. Acetylcholine caused a dose-dependent vasodilation that was significantly (P < .01) lower in essential hypertensive patients than in normotensive control subjects. However, a significant negative correlation was observed between acetylcholine-induced vasodilation and patient age in both normotensive (r = -.86, P < .001) and hypertensive (r = -.85, P < .001) patients. In contrast, vasodilation to sodium nitroprusside was similar in normotensive control subjects and essential hypertensive patients with a poorer inverse correlation with patient age (normotensive control subjects, r = -.37; hypertensive patients, r = -.36) compared with acetylcholine.

CONCLUSIONS

The present data indicate that there is a blunted response to acetylcholine with advancing age in both normotensive control subjects and essential hypertensive patients, suggesting that aging is associated with reduced endothelium-dependent vasodilation in humans.

Three-dimensional in vivo planum temporale reconstruction

We describe a new multistep technique for three-dimensional reconstruction and analysis of the in vivo planum temporale (PT) based on the manipulation of magnetic resonance raw data obtained with a special protocol. Measurements of left and right plana confirm previous neuroanatomical descriptions of a larger left planum temporale. This method can be easily adopted, allowing anatomically valid PT measurements.

Information processing strategy to remediate Wisconsin Card Sorting Test performance in schizophrenia: a pilot study

A modified procedure for administering the Wisconsin Card Sorting Test, focusing on a hypothesized deficit of organizational strategy in information processing, was used to administer the test to 20 schizophrenic patients. By using this procedure, 61.5% of the poor performers (eight of 13) were dramatically transformed into good performers without any task instruction or reinforcement. The results, albeit preliminary, support the hypothesis and the possibility of remediating the task performance of some schizophrenic patients.

Magnetic resonance imaging findings of amygdala-anterior hippocampus shrinkage in male patients with schizophrenia

Recent magnetic resonance imaging (MRI) studies found abnormalities of medial temporal lobe and basal ganglia structures. We used an inversion recovery (IR) protocol with the assistance of the Talairach atlas to identify neuroanatomical regions of interest in 19 male schizophrenic patients and 14 matched control subjects. The patient group showed smaller amygdala-hippocampus volume as compared with normal control subjects. This finding was more pronounced for the left side, although no diagnosis X side interaction was present. Third ventricle volume was also enlarged in schizophrenic patients. Trends toward an overall reduction of basal ganglia (striatum and lenticular nucleus) and limbic structures and toward an increase in ventricle-brain ratio were also seen. The study confirms previous evidence of mesial temporal lobe shrinkage, more evident on the left side in a group of relapsing noninstitutionalized male schizophrenic patients.

Effect of potassium on vasodilation to acetylcholine in essential hypertension

Patients with essential hypertension show impaired endothelium-dependent vasodilation induced by acetylcholine. Because dietary potassium supplementation increases endothelium-dependent relaxations to acetylcholine in hypertensive rats, we designed the present study to investigate whether potassium increases endothelium-dependent vasodilation in essential hypertensive patients. Therefore, in patients with essential hypertension (n = 13) and in normotensive control subjects (n = 13) we evaluated the effect of intrabrachial potassium chloride (0.2 mmol/min) on forearm blood flow (strain-gauge plethysmography) modifications induced by intrabrachial acetylcholine (0.15, 0.45, 1.5, 4.5, and 15 micrograms/100 mL forearm tissue per minute). In both groups of patients, potassium chloride infusion augmented local plasma potassium concentrations. Furthermore, in essential hypertensive patients but not in normotensive subjects it increased the vasodilating effect of the first three infusion rates of acetylcholine. In contrast, in seven adjunctive essential hypertensive patients, potassium chloride did not alter intrabrachial sodium nitroprusside-induced forearm vasodilation (1, 2, and 4 micrograms/100 mL forearm tissue per minute). Finally, to evaluate the role of nitric oxide on potassium-dependent facilitation of acetylcholine-induced vasodilation in essential hypertension, we studied the effect of intrabrachial NG-monomethyl L-arginine (100 micrograms/100 mL per minute) in another group of seven hypertensive patients. Vasodilation to acetylcholine was again increased by potassium chloride; NG-monomethyl L-arginine slightly blunted the vasorelaxing effect of acetylcholine but abolished the potentiating effect of potassium.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic and recurrent appendicitis are uncommon entities often misdiagnosed

Those having chronic and recurrent appendicitis represent a small portion of patients with disorders of the appendix. We present a series of nine patients who underwent appendectomy for chronic or recurrent appendicitis at The Johns Hopkins Hospital, Baltimore, Maryland, between July 1984 and October 1992. There were seven women and two men (median age of 30 years, range of 15 to 63 years). All patients presented with pain in the right lower quadrant or lower abdomen of three or more weeks duration (mean of 16.0 +/- 8.4 months, range of three weeks to seven years), had no alternative diagnosis to account for the symptoms, had pathologic evidence of chronic inflammation or fibrosis of the appendix and had complete relief of the symptoms after appendectomy. Although the patients presented herein had clinical and pathologic evidence for recurrent or chronic appendicitis, careful review of the course of each patient before surgical referral revealed at least one episode of acute pain in the abdomen consistent with acute appendicitis managed by nonoperative means. This suggests that, while recurrent acute appendicitis and chronic appendicitis do occur, they can be avoided by the accurate diagnosis and operative management of acute appendicitis. We conclude that acute appendicitis can resolve spontaneously and recur repeatedly in the same individual; in the evaluation of a patient with abdominal pain, a history of prior similar episodes of pain should never dissuade one from considering the diagnosis of acute appendicitis, and recurrent acute appendicitis and chronic appendicitis should be considered in the differential diagnosis of recurrent pain in the lower abdomen.

Rupture of the right diaphragm following blunt trauma in an infant: case report

Traumatic diaphragmatic rupture is a rare childhood injury and is often difficult to diagnose. This is particularly true in infants. We present the case of a 3-month-old infant with traumatic rupture of the right diaphragm that became clinically apparent only after extubation. The diagnosis can often be made on the basis of chest radiography and clinical signs. Surgical treatment is required. Some phrenic nerve injuries can be anticipated and late sequelae may result.

Vascular renin-angiotensin system and sympathetic nervous system activity in human hypertension

Experimental data indicate the existence of a vascular tissue renin-angiotensin system in several different vessels from various animal models. Active renin can be locally synthesized into the vessel wall or taken up from circulating plasma to produce vascular angiotensin II. Using the human forearm technique, we produced evidence indicating the release of active and inactive renin and of angiotensin II from the vessels of hypertensive patients. Moreover, the production of vascular angiotensin II seems to be strictly correlated to the circulating renin profile, suggesting the possibility that vascular renin might be at least partially taken up from plasma. To investigate a possible function of the vascular renin-angiotensin system, we studied its interaction with sympathetic neurotransmission in essential hypertensive patients. In line with animal studies, vascular angiotensin II increases the vasoconstriction induced by the stimulation of the sympathetic nervous system through the potentiation of noradrenaline release at a presynaptic level, and this effect seems to be mediated by beta-adrenoceptor activation. This facilitating effect on sympathetic neurotransmission exerted by vascular angiotensin II can be antagonized by both angiotensin II antagonists and angiotensin-converting enzyme inhibitors.

Vasodilation to acetylcholine in primary and secondary forms of human hypertension

Endothelium-dependent vasodilatation to acetylcholine is reduced in the forearm of essential hypertensive patients. To investigate whether endothelium-dependent vasodilatation is reduced also in secondary hypertension, we evaluated the effects of an intrabrachial infusion of acetylcholine on forearm blood flow (strain-gauge venous plethysmography) in essential hypertensive (n = 12), primary aldosteronism hypertensive (n = 8), and renovascular hypertensive (n = 8) patients and normotensive control subjects (n = 12). To further evaluate the role of a cyclooxygenase-dependent endothelium-derived vasoconstrictor substance, we repeated the infusion of acetylcholine in the presence of indomethacin. The effect of the direct vasodilator sodium nitroprusside was also examined. The vasodilatation to acetylcholine was reduced in essential, primary aldosteronism, and renovascular hypertensive patients compared with normotensive subjects. In contrast, the vasodilatation induced by sodium nitroprusside was similar in all groups of patients and control subjects. In the presence of indomethacin, the vasodilator effect of acetylcholine was increased in essential hypertensive patients but not in normotensive or in secondary hypertensive individuals. These data demonstrate an impairment of endothelium-dependent vasodilation in renovascular and primary aldosteronism hypertensive patients and indicate that a cyclooxygenase-dependent vasoconstrictor mechanism participates in the blunting of endothelium-dependent vasodilation in essential hypertensive patients.

Tension pneumothorax as a presentation of traumatic diaphragmatic hernia

Spontaneous pneumothorax and tension pneumothorax are being increasingly recognized as complications of traumatic diaphragmatic hernia, particularly when presentation is delayed. This underscores the importance of suspecting the diagnosis of diaphragmatic hernia in patients with a recent or remote history of blunt or penetrating trauma to the chest or abdomen and an unusual or an atypical thoracic process. Once the diagnosis is suspected, confirmation with contrast studies, CT, or MRI should be obtained and surgical repair undertaken without delay.

Endothelium-dependent forearm vasodilation is reduced in normotensive subjects with familial history of hypertension

Endothelium-dependent vasodilation is reduced in essential hypertensive subjects. To evaluate whether this abnormality is a primary defect or is a consequence of blood pressure increment, in offspring of essential hypertensive and normotensive subjects (n = 13 subjects for each group) matched for age, sex, body weight, and blood pressure, we studied the response of forearm vasculature to acetylcholine (ACh) (an endothelium-dependent vasodilator), sodium nitroprusside (a direct vasodilator of vascular smooth muscle), and forearm ischemia (13 min plus 1 min of exercise) to induce maximal vasodilation. Drugs were infused into the brachial artery at cumulative doses (ACh: 0.15, 0.45, 1.5, 4.5, and 15 micrograms/100 ml of forearm tissue/min; sodium nitroprusside: 1, 3, and 10 micrograms/100 ml of forearm tissue/min) while forearm blood flow was measured by strain-gauge venous plethysmography. The intra-arterial blood pressure and heart rate were continuously monitored. Despite a comparable forearm vascular response to sodium nitroprusside and to forearm ischemia, the effect of ACh was significantly (p < 0.001) reduced in offspring of hypertensive subjects compared to the offspring of normotensive subjects. These data indicate that ACh-mediated forearm vasodilation is reduced in normotensive subjects with a familial history of essential hypertension, a finding that suggests that endothelium dysfunction can precede the appearance of hypertension and that this abnormality might play a role in the pathogenesis of essential hypertension.

Planum temporale in schizophrenia: a magnetic resonance study

Magnetic resonance imaging (MRI) scans were used to examine the size and asymmetry of the planum temporale (PT) in 20 schizophrenic patients and 12 strictly matched healthy volunteers. PT lengths from coronal sections were measured and then summed to obtain an estimate of their areas. Schizophrenics showed the lack of the physiological PT area asymmetry evidenced in the control sample and a statistically significant diagnosis by side interaction was observed (F = 4.96; p less than 0.05). The study of PT asymmetry could permit us to better analyse the role of laterality in the pathophysiology of schizophrenia.

Noncontrast and contrast enhanced MR imaging in the evaluation of partial ureteral obstruction: an experimental study in the micropig

Twelve Yucatan micropigs (3 controls; 3 sham-operated; 6 with unilateral obstruction) were studied to assess the value of noncontrast and contrast-enhanced (Gadolinium-DTPA) magnetic resonance (MR) imaging in the evaluation of partial ureteral obstruction. MR findings were correlated with findings of quantitative (Tc-99m-DMSA) scintigraphy, and histology. On noncontrast T1-weighted images, the normal porcine kidney demonstrated good corticomedullary contrast (CMC = 16.8% +/- 5.0). Five minutes after administration of Gd-DTPA, there was enhancement of the renal cortex (+24.4% and medulla (+46.2%), and CMC was no longer discernible. Enhancement of the urine within the collecting system (+119.1%) was also observed. The obstructed kidneys demonstrated marked thinning of the renal parenchyma and decreased signal intensity on noncontrast T1- and T2-weighted images (P less than 0.01). Urine in the dilated collecting system did not differ significantly from urine in controls except in the three animals with urinary tract infection (P less than 0.05). Five minutes following injection of Gd-DTPA, there was enhancement of the renal parenchyma in all kidneys. Excretion was seen in three pigs and no excretion in two. Thus, useful information can be obtained in partial ureteral obstruction from both pre-contrast and Gd-DTPA-enhanced MR images of the kidney.

Effects of a phorbol ester on mouse eggs: dissociation of sperm receptor activity from acrosome reaction-inducing activity of the mouse zona pellucida protein, ZP3

Biologically active phorbol esters or a diacylglycerol induce mouse eggs to modify the zona pellucida such that sperm receptor activity is retained but the ability of bound sperm to undergo a complete acrosome reaction is lost (Y. Endo, R.M. Schultz, and G.S. Kopf. 1987. Dev. Biol. 119, 199-209). We now show that purified ZP3 from 12-O-tetradecanoyl phorbol-13-acetate (TPA)-treated eggs possesses full sperm receptor activity but has lost its ability to induce a complete acrosome reaction. The modification of the acrosome reaction-inducing activity of ZP3 from these TPA-treated eggs differs from ZP3 isolated from two-cell embryos, which cannot initiate the acrosome reaction. These results demonstrate the dissociation of the two biological activities of ZP3 and may provide a system to assess the components of ZP3 involved in the acrosome reaction.

Effects of protein kinase C activators on germinal vesicle breakdown and polar body emission of mouse oocytes

Protein phosphorylation mediated by cAMP-dependent protein kinase is instrumental in maintaining meiotic arrest of mouse oocytes. To assess whether protein phosphorylation mediated by calcium/phospholipid-dependent protein kinase (protein kinase C) might also inhibit the resumption of meiosis, we treated oocytes with activators of this enzyme. The active phorbol esters 12-O-tetra-decanoyl phorbol-13-acetate (TPA) and 4 beta-phorbol 12,13-didecanoate (4 beta-PDD) inhibited germinal vesicle breakdown (GVBD), as did a more natural activator of protein kinase, C, sn-1,2-dioctanoylglycerol (diC8). An inactive phorbol ester, 4 alpha-phorbol 12,13-didecanoate (4 alpha-PDD), did not inhibit GVBD. We then examined whether protein kinase C activators inhibit a step in the cAMP-modulated pathway that regulates resumption of meiosis. TPA did not inhibit the maturation-associated decrease in oocyte cAMP. Microinjected heat-stable protein inhibitor of cAMP-dependent protein kinase failed to induce GVBD in the presence of TPA. Both TPA and diC8 partially inhibited specific changes in oocyte phosphoprotein metabolism that are tightly correlated with resumption of meiosis; these agents also induced the apparent phosphorylation of specific oocyte proteins. These results suggest that protein kinase C activators may inhibit resumption of meiosis by acting distal to a decrease in cAMP-dependent protein kinase activity, but prior to changes in oocyte phosphoprotein metabolism that are presumably required for resumption of meiosis. Finally, we compared the effects of db-cAMP and protein kinase C activators on polar body emission following GVBD. TPA, 4 beta-PDD or diC8, but not 4 alpha-PDD or db-cAMP, inhibited polar body emission in a dose-dependent manner. The morphology and cytology of oocytes in which polar body emission was inhibited by TPA or 4 beta-PDD differed from that of oocytes treated with diC8. Thirty to 60% of the former were round in shape and exhibited a clump of chromosomes but no spindle; the remainder were distended in shape and exhibited a metaphase I spindle. All oocytes treated with diC8, however, were round, had dispersed chromosomes, and no spindle. These results suggest that, in contrast to resumption of meiosis, polar body emission is inhibited by activation of protein kinase C but not cAMP-dependent protein kinase.

Involvement of cAMP-dependent protein kinase and protein phosphorylation in regulation of mouse oocyte maturation

We report the results of experiments which support the hypothesis that, in mouse oocytes, a decrease in intraoocyte cyclic AMP (cAMP) initiates meiotic maturation; oocytes microinjected with cyclic nucleotide phosphodiesterase (PDE) underwent germinal vesicle breakdown (GVBD) in the presence of 3-isobutyl-1-methylxanthine (IBMX), which inhibited GVBD both in oocytes not injected with PDE and in oocytes injected with heat-inactivated PDE. Cyclic AMP-dependent protein kinase (PK) has been proposed to mediate maintenance of meiotic arrest by cAMP. In support of this hypothesis is the observation that 2'-deoxy cAMP, which does not activate PK, did not maintain meiotic arrest as did cAMP; this result was obtained both by microinjection of these compounds and by incubating oocytes in the presence of their membrane-permeable N6-monobutyryl derivatives. Furthermore, microinjection into oocytes of the heat-stable inhibitor of PK, PKI, induced GVBD in the presence of either dibutyryl cAMP (dbcAMP) or IBMX. Meiotic arrest was maintained in the absence of dbcAMP or IBMX, however, by microinjected catalytic subunit of PK, but not by catalytic subunit coinjected with PKI. In addition, specific changes in oocyte phosphoproteins that preceded resumption of meiosis were induced, in the presence of dbcAMP, by microinjected PKI; these changes were also tightly coupled with commitment of oocytes to resume meiosis. These results are discussed in terms of our model for regulation of meiotic arrest and maturation.