The effects of epinine on arterial blood pressure and regional vascular resistances in anesthetized rats

1. We carried out experiments in anesthetized rats to study the hemodynamic effects of intravenous injections of epinine. 2. Epinine (1-320 micrograms/kg) produced a biphasic effect on mean arterial blood pressure (n = 30). At doses lower than 40 micrograms/kg, arterial blood pressure decreased (by as much as 21.5 +/- 3.4%), though at higher doses it increased dose dependently (by as much as 73.2 +/- 14.5%). Epinine also produced bradicardia in a dose-dependent manner (by as much as 26.4 +/- 4.9%). Sulpiride (100 micrograms/kg) suppressed the hypotensive effect of epinine but did not change the hypertensive effect. In the presence of prazosin (1,000 micrograms/kg), arterial blood pressure remained significantly decreased at all doses of epinine. Neither sulpiride nor prazosin changed the bradycardic effect of epinine. 3. Prazosin produced a significant decrease in renal vascular resistance. Epinine (5 micrograms/kg) after prazosin reverted the effects of prazosin in renal vascular resistance, without any significant modification in the renal blood flows. However, 20 micrograms/kg epinine increased the renal vascular resistances and, moreover, produced a significant decrease in the blood flows of both kidneys. Neither prazosin nor epinine produced modifications in the intestinal vascular bed. 4. Although epinine possesses significant dopamine and alpha-adrenergic activities that are involved in the biphasic effect of the agent on mean arterial blood pressure in anesthetized rats, in the presence of prazosin, it is not possible to manifest dopaminergic activity involved in the increase in renal or mesenteric blood flow; this may be due to the low tone of the vascular wall induced by the alpha-adrenergic antagonist, though an alpha 2-activity cannot be discarded.

In vivo insulin-dependent glucose uptake of specific tissues is decreased during aging of mature Wistar rats

Aging has been associated with peripheral insulin resistance in both humans and rats. However, the specific tissues that become insensitive to insulin before glucose homeostasis is altered remain to be elucidated. In the present work we studied the glucose metabolic index of a number of tissues known to be insulin sensitive in 3- and 24-month-old Wistar rats by measuring 2-deoxy-D-[1-3H]glucose uptake both under euglycemic-hyperinsulinemic conditions and in the basal state. Analysis of the glucose infusion rate to maintain normoglycemia during the clamp confirmed that the old rats show overall insulin resistance at both saturating and subsaturating insulin concentrations. The maximal response of glucose uptake to insulin as well as insulin sensitivity in red and white quadriceps were unaltered in old rats. In contrast, glucose uptake by soleus and diaphragm was poorly stimulated in old animals, and a marked decrease in insulin sensitivity was observed in both tissues. In heart, only the sensitivity to the hormone, not the maximal response, was impaired in old rats. In white adipose tissue, no significant stimulation was detected. We conclude that during aging in Wistar rats and before fasting plasma insulin and glucose levels become altered, specific tissues develop insulin resistance, whereas other remain insulin sensitive. We postulate that fat tissue plays a qualitative important role in eliciting the insulin resistance in old animals. Due to the metabolic characteristics of the aged Wistar rat, the changes reported might reflect what occurs in nonobese elderly humans, nongenetically committed to develop type 2 diabetes.

A prospective study of adverse drug reactions as a cause of admission to a paediatric hospital

1. A total of 512 consecutive paediatric hospital admissions of children 2 years old or less were evaluated to assess the extent and pattern of admission caused by suspected adverse drug reactions (ADRs). the proportion of suspected ADRs related to hospital admissions was 4.3%. 2. The organ-systems most commonly implicated were the central nervous system (40.5%), digestive system (16.7%), and skin and appendages (14.3%). Together, they accounted for 71.5% of admissions attributed to ADRs. The most common clinical manifestations inducing admission were convulsions (4 cases), dizziness (4), vomiting (3), and tremor, fever, itching and apnoea (2 cases each). 3. The four classes of drugs most frequently suspected in admissions due to ADRs were respiratory drugs (35%), anti-infective agents (25%), drugs active on the central nervous system (15%) and drugs used in dermatology (10%). The most common drugs related to ADRs were a combination of chlorpheniramine, diphenhydramine, phenylephrine, guaiphenesin and salicylic acid (4 cases), followed by fenoterol, adrenaline, paracetamol, DTP vaccine and antipolio vaccine (2 cases each). 4. There were no significant differences between children older and younger than 1 year (odds ratio 0.89; 95% CI 0.37-2.17) or between the sexes as regards hospital admittance due to suspected ADRs (odds ratio 1.94; 95% CI 0.72-5.42). 5. The results of this kind of study may be influenced by patterns of drug utilization. Nevertheless, the lack of specific studies of drug effects in young children makes it desirable to carry out pharmacoepidemiological studies in this age group.

Are the Adverse Drug Reactions of Amoxycillin and Amoxycillin-Clavulanic Acid Similar?

In an attempt to assess the relative toxicity of amoxycillin and amoxycillin-clavulanic acid, we compared the adverse drug reactions reports collected using the spontaneous reporting system of a Regional Drug Surveillance Centre of Spain for both drugs between November 1986 and December 1992. During the 7-year period 1986-92, the 247 reports of amoxycillin-clavulanic acid represent twice the number of reports of amoxycillin alone, and the number of reports related with sales received concerning the association were higher than those concerning amoxycillin alone. The adverse effects classified as severe were quantitatively and qualitatively similar for both drugs and gastrointestinal and skin are the most common system-organ affected by both drugs. With amoxycillin-clavulanic acid there is a higher proportion of stomatological reactions reported and a later onset of adverse drug reactions related with oropharyngeal lesions, and the reaction of the resistance mechanism when compared with the other organs and systems affected. The duration of the adverse drug reactions to amoxycillin-clavulanic acid is longer than for amoxycillin alone.

IN CONCLUSION

(i) the adverse drug reactions profile of both drugs is different; (ii) the higher reporting rate for amoxycillin-clavulanic acid may be due to more recent marketing; and (iii) amoxycillin-clavulanic acid produces proportionately more gastrointestinal and fewer skin adverse reactions than amoxycillin alone.

Isolated human colon strips as a pharmacological tool

The spontaneous activity of isolated human colon strips was studied to obtain homogeneous results with a reproducible model. The strips of macroscopically normal appearance were mounted in an organ bath containing Krebs solution at 32 degrees C or Tyrode solution at 37 degrees C. Mechanical activity was recorded by an isometric transducer. Spontaneous motility did not occur in all preparations. Moreover, when observed, it could not always be evaluated. The percentage of strips with spontaneous activity was lower with Tyrode solution than with Krebs solution (65 vs. 81%). KC1 did not induce a plateau contraction. Acetylcholine induced concentration-dependent contractions, with a significantly different pD2: 4.43 +/- 0.39 and 5.59 +/- 0.16 for Krebs and Tyrode, respectively. Isoprenaline abolished spontaneous motility in Krebs solution. Only 20% of specimens presented evaluable motility. Krebs solution may be the best conditions for studying the effects of drugs on spontaneous motility, while Tyrode solution can be used to investigate the effects of contractile agents.

Arterio-jugular differences of oxygen (AVDO2) for bedside assessment of CO2-reactivity and autoregulation in the acute phase of severe head injury

Autoregulation and CO2-reactivity can be impaired independently of each other in many brain insults, the so-called 'dissociated vasoparalysis'. The theoretical combination of preserved CO2-reactivity and impaired or abolished autoregulation can have many clinical implications in the daily management of brain injured patients. To optimize their treatment, a bedside assessment of autoregulation and CO2-reactivity is desirable. When cerebral metabolic rate of oxygen is constant, changes in arterio-jugular differences of oxygen (AVDO2) reflect changes in CBF. In these situations relative changes in AVDO2 can be viewed as inverse changes in CBF and used as an evaluation method of CO2-reactivity and autoregulation. In 39 consecutive severe head injury patients with a mean age of 28 +/- 17 years and a diffuse brain injury, cerebrovascular response to changes in pCO2 was tested in the acute phase after injury (18 +/- 8 hours). In 28 of those cases autoregulation was also assessed. A relative CBF value (1/AVDO2) was calculated from baseline AVDO2 and was expressed as 100%. Changes in 1/AVDO2 after inducing pCO2 changes give a good estimate of changes in global CBF. Two different indexes were calculated for CO2-reactivity: 1) absolute CO2-reactivity (CO2RABS) and 2) percentage reactivity (CO2R%). CO2R% was used to separate patients with impaired/abolished CO2-reactivity from those with preserved CO2-reactivity. Patients with CO2R% above 1% were considered in the intact CO2-reactivity group and patients in whom CO2R% was below or equal to 1% were included in the impaired/abolished CO2-reactivity group. Only five cases (12.8%) presented an impaired/abolished CO2-reactivity. AVDO2 response to induced hypertension was studied in a subset of 28 patients. Phenylephrine was used to increase MABP about 25%. All AVDO2 values were corrected for changes in pCO2. Patients with changes in 1/AVDO2 less than or equal to 20% were included in the intact autoregulation group. Patients with estimated CBF changes above 20% were classified as having an impaired autoregulation (impaired/abolished). In 12 patients (43%) autoregulation was intact. In the remaining 16 patients (57%) autoregulation was imparied. Of the 28 cases, CO2-reactivity was impaired in only five cases. All patients with an impaired CO2-reactivity also had an impaired autoregulation. Monitoring relative changes in AVDO2 permits a reliable study of CO2-reactivity and autoregulation at the bedside. Introducing these variables into the day-to-day management should be considered in treatment protocols.

Exercise-induced asthma prophylaxis in athletes using inhaled nedocromil sodium

This open labelled, group comparative, cross over study, was carried out to analyze the efficacy of two dosages of Nedocromil sodium (NS) in the prophylaxis of Exercise Induced Asthma (EIA). 13 athletes (6 males, 7 females), aged: 12-38 years, were studied measuring their EIA by forced spirometries prior and at 1, 3, 5, 10, 15 and 30 minutes post treadmill test. Four mg of NS were administered via inhalation chamber 30 minutes prior to the second test; prior to the third one;: NS at a dose of 4 mg every 8 hours during four weeks plus 4 mg of NS 30 minutes before it. In the baseline exercise test, a 33.6 +/- 10.5 percent decrease of FEV1 was observed; 12.6 +/- 11.4 in the second one, and 9.7 +/- 9.76 in the third test. A protection index higher than 30% was obtained in 9 cases of the second test (81.5 +/- 16.2%), and in 10 of the third one (77.2 +/- 15.3%). Nedocromil sodium (4 mg prior to exercise) is effective for EIA prophylaxis. Although no significant differences exist between both dosages, a greater protection index is reached after NS sustained administration.

No evidence for dopamine-induced relaxation in isolated human mesenteric arterial strips from elderly patients

1. We investigate the effects of dopamine in isolated mesenteric artery from elderly patients. 2. Noradrenaline (10(-11) to 10(-4) M) and dopamine (2.7 x 10(-6) to 1.4 x 10(-3) M) induced a concentration-dependent contraction that was antagonized by prazosin. Fenoldopam (10(-8) to 10(-4) M) and clonidine (10(-9) to 10(-4) M) did not produce any contractile effects. 3. Potassium chloride (80 mM) produced a well-maintained plateau contraction and dopamine-induced contraction in these conditions, which was decreased by prazosin (10(-8) M). Neither fenoldopam nor isoprenaline (10(-10) to 10(-5) M) modified the well-maintained plateau. 4. Our results suggest that post-synaptic dopamine receptors are not present in this preparation but alpha1-adrenoceptors are present.

Posterior fossa reconstruction: a surgical technique for the treatment of Chiari I malformation and Chiari I/syringomyelia complex--preliminary results and magnetic resonance imaging quantitative assessment of hindbrain migration

Experimental models have shown that Chiari I malformation is a primary paraaxial mesodermal insufficiency occurring after the closure of the neural folds takes place. According to these hypotheses, a small posterior fossa caused by an underdeveloped occipital bone would be the primary factor in the formation of the hindbrain hernia. The main objective in the surgical treatment of Chiari I malformation and related syringomyelia is directed to restore normal cerebrospinal fluid dynamics at the craniovertebral junction. The most widely accepted surgical approach is to perform a craniovertebral decompression of the posterior fossa contents with or without a dural graft. It has been emphasized that suboccipital craniectomy should be small enough to avoid downward migration of the hindbrain into the craniectomy. This slump of the hindbrain has been verified by studies using postoperative assessment by magnetic resonance imaging. Our aim in this study is to present a modification of the conventional surgical technique, which we have called posterior fossa reconstruction (PFR). Ten patients were operated on using this technique and compared with a historical control group operated on with the classic approach of making a small suboccipital craniectomy, opening the arachnoid, and closing the dura with a graft. To evaluate the morphological results in both groups objectively, preoperative and postoperative measurements of the relative positions of the fastigium and upper pons above a basal line in the midsagittal T1-weighted magnetic resonance images were obtained. In those cases with syringomyelia, syringo-to-cord ratios were calculated. The mean age of the PFR group was 35 +/- 16 years (mean +/- SD); in the control group it was 35.2 +/- 12 years. In the PFR group, the formation of an artificial cisterna magna was observed in every case; it was observed in only one case in the control group. An upward migration of the cerebellum was seen in all cases in the PFR group, with a mean ascent of the fastigium of 6.2 mm. A significant downward migration of the cerebellum was observed in seven cases in the control group. No significant differences were found in both groups when comparing syringo-to-cord ratios. This leads us to conclude that PFR is more effective than conventional surgical approaches in restoring the normal morphology of the craniovertebral junction. This allows cranial ascent of the hindbrain verified by magnetic resonance imaging and good short-term clinical results. Because PFR is mainly an extraarachnoidal approach, complications related to surgery using this technique can be kept to a minimum.

[Adverse reactions from angiotensin-converting enzyme inhibitor drugs reported by the yellow card]

BACKGROUND

The aim of the present study was to analyze the adverse reactions (AR) to captopril (CP) and enalapril (EN) reported by voluntary notification by the yellow card (YC) over the first five years of the foundation of the Drug Surveillance Center of the Valencian Community.

METHODS

The AR described were classified by organs and systems, evaluating the age and the sex of the patient, the indication for the drug, dosage used, and the level of health care assistance received since notification. Previous knowledge of the reported AR was analyzed, as was the possible relation of causality with the drug and severity of the same. The rates of notification were calculated with respect to the consumption of both drugs, expressed in daily dosage defined (DDD).

RESULTS

Two hundred one YC were evaluated, 111 for CP and 90 for EN referring 160 and 133 clinical manifestations, respectively. The rate of notification was 2.51 YC/million DDD for CP and 5.57 for EN. The AR in the respiratory tract were the most frequently reported with cases of dry cough representing 33.7% of the total YC for CP and 33.8% for EN. Cutaneous AR followed for both drugs. Angioedema was reported in 0.09 AR/million DDD for CP and 0.56 for EN. Reactions were most frequently observed in patients over the age of 50 with a predominance of the female sex, being usually slight and with 80% having been notified from primary health care centers.

CONCLUSIONS

The high number of reports of cough demonstrate that this is the most frequently observed adverse reaction. The distribution of reactions and the characteristics of the patients with the same coincide with other studies. The low number of yellow cards reporting severe adverse reactions may support the favorable safety profile of this pharmacologic group, or, to the contrary, be a consequence of the under-reporting of adverse reactions.

[An evaluation of the control of antihypertensive treatment by using ambulatory arterial pressure monitoring]

BACKGROUND

Outpatient monitoring of blood pressure (OPMBP) allows more precise values to be obtained and to observe the oscillations over 24 hours. Although this is widely used in the estimation of the antihypertensive efficacy of drugs, few studies have been performed on the evaluation of the control in treated patients.

METHODS

One hundred eight patients (M/F 55/53, mean age 50 +/- 11 years, body mass index 29.7 +/- 4.4) with essential high blood pressure (HBP) were included in the study fulfilling the criteria of: a) DBP > 95 mmHg on 3 visits over a 2 month period, b) antihypertensive treatment maintained over 2 months and c) normal renal function (Cr < 115 mumol/l). Twenty-five patients were considered as having resistant HBP on presenting BP > 150/100 mmHg during the course of treatment with well combined and adequately dosed drugs, one of which was a diuretic. Twenty-four hour OPMBP was carried out in all the patients on a normal work day with a SpaceLabs 90202 monitor. Acceptable control was considered when the mean of the DBP throughout the day (08:00-22:00) was < 85 mmHg.

RESULTS

Out of all the patients studied, 67 (62%) showed acceptable control and 27 (25%) showed normotensive values. Among the 25 refractory hypertensive patients 20 (40%) showed an acceptable control and 7 (28%) normotensive values. The only clinical difference between both groups was the presence of a greater degree of organic repercussion in the inadequately controlled group (chi 2 p < 0.05). Eight patients showed medium values of SBP over 24 h < 120 mmHg and 2 medium values of DBP over 24 h < 70 mmHg.

CONCLUSIONS

Outpatient monitoring of blood pressure may be useful in the evaluation of the control of high blood pressure in patients submitted to pharmacologic treatment who do not present an adequate reduction in the values of blood pressure.

[Epididymal neoplasms. New case report. Report of an adenomatoid tumor]

Presentation of the case of one patient with epididymal adenomatoid tumour presenting as episodes of inguino-scrotal discomfort. With no evidence of relapse, the case is monitored three years after surgery. On the lines of the literature review presented, a series of considerations on what has been a controversial histogenesis are made. The reason for this report is the differential diagnosis which conditions all inguino-scrotal processes with torpid evolution.

Early ischaemia after severe head injury. Preliminary results in patients with diffuse brain injuries

Ischaemic brain lesions still have a high prevalence in fatally head injured patients and are the single most important cause of secondary brain damage. The present study was undertaken to explore the acute phase of severely head injured patients in order to detect early ischaemia using Robertson's approach of estimating cerebral blood flow (CBF) from calculated arterio-jugular differences of oxygen (AVDO2), lactates (AVDL), and the lactate-oxygen index (LOI). Twenty-eight cases with severe head injury were included (Glasgow Coma Scale Score below or equal to 8). All patients but one had a non-missile head injury. All the patients had a diffuse brain injury according to the admission CT scan. ICP measured at the time of admission was below 20 mmHg in 17 cases (61%). All patients were evaluated with the ischaemia score (IS) devised in our center to evaluate risk factors for developing ischaemia. Mean time from injury to the first AVDO2/AVDL study was 23.9 +/- 9.9 hours. According to Robertson's criteria, 13 patients (46%) had a calculated LOI (-AVDL/AVDO2) value above or equal to 0.08 and therefore an ischaemia/infarction pattern in the first 24 hours after the accident. Of the 15 patients without the ischaemia/infarction pattern, in three cases the CBF was below the metabolic demands and therefore in a situation of compensated hypoperfusion. No patient in our series had hyperaemia. Comparing different variables in ischaemic and non-ischaemic patients, only arterial haemoglobin and ischaemia score (IS) was significantly different in both groups. The ischaemia score had mean of 4.3 +/- 1.7 in the ischaemic group and 2.7 +/- 1.4 in non-ischaemic patients (p = 0.01). It is concluded that ischaemia is highly prevalent in the early period after severe head injury. Factors potentially responsible of early ischaemia are discussed.

Effect of histamine on the longitudinal and circular muscle of the oestrogen dominated rat uterus

The response of the longitudinal and circular myometrial strips to histamine was studied in oestrogen-treated rats. Histamine produced a dose-related inhibitory response in KCl-contracted longitudinal and circular uterine strips. Histamine was equipotent in producing the relaxant response but the maximal effect achieved in the longitudinal muscle was higher than the circular one. Ranitidine antagonized the histamine-induced relaxation with a similar dose ratio in both longitudinal and circular strips. Clemizole and reserpine treatment did not produce any modification of the dose-response curve to histamine. In the longitudinal and circular strips which were not preconstricted by KCl, neither histamine nor 2-pyridylethylamine, even in strips pretreated with ranitidine, produced any effect when added to the organ bath. Our results show that the response of histamine in both longitudinal and circular uterine layers of the oestrogen-treated rats are mediated exclusively by histamine H2-receptors.