Improvement of bioavailability of poorly absorbed drugs. III. Oral acute toxicity and local irritation of medium chain glyceride

Oral acute toxicity of medium chain glyceride (MCG) was studied in mice and rats. In mice and rats, clinical signs such as irregular respiration, laxity of movement, staggering gait and loss of righting reflex appeared after single oral administration of MCG at a relatively large dose. The LD50 values determined in male and female mice were 26.9 and 28.5 ml/kg, and in male and female rats were 27.4 and 26.7 ml/kg, respectively. In order to evaluate the biological safety of MCG suppository of cefmetazole sodium (CMZ), its local irritation on the mucous membrane was studied. Primary eye irritation of MCG suppository of CMZ was studied in rabbits. Although mild irritation was seen in conjunctivae, no remarkable changes were observed in cornea and iris. Furthermore, primary effect of MCG suppository of CMZ on the rectal mucous membrane was studied macro- and microscopically. It was observed that remarkable histological changes of rectal mucous membrane by MCG suppository of CMZ were not observed in all animals used.

Improvement of bioavailability of poorly absorbed drugs. IV. Mechanism of the promoting effect of medium chain glyceride on the rectal absorption of water soluble drugs

The mechanisms of the promoting effect of medium chain glyceride (MCG) containing glyceryl mono-, di- and tri-caprylate on rectal absorption of water soluble drugs were investigated. It was found that the solubility behavior of the drugs in mucosal fluids on the surface of the membrane are critical factor for the enhanced rectal absorption. Moreover, the drugs to be readily absorbed from MCG base may be ones of low partition coefficients to MCG phase as well as high solubility in water. And it was found that MCG can't be absorbed from the rectum, different from oral administration, suggesting an interaction of MCG with absorption membrane, rather than the carrier effect of MCG itself. Furthermore, from the results in the pretreatment experiments and additional administration of MCG alone, it was suggested that the interactions of MCG with the membrane components, as well as the induction of biological or physiological changes, may be at least partly responsible for the promoting effect of MCG.

Improvement of bioavailability of poorly absorbed drugs. V. Effect of surfactants on the promoting effect of medium chain glyceride for the rectal absorption of beta-lactam antibiotics in rats and dogs

The promoting effects of medium chain glyceride (MCG) on the rectal absorption of beta-lactam antibiotics were compared among various experimental animals (such as rats, rabbits and dogs). The plasma levels of cefmetazole (CMZ) after rectal administration, when MCG was used as the vehicle, significantly increased in all animals, but the bioavailability of CMZ was greatly varied among the animal species; the bioavailability of CMZ in dogs was apparently less than those in other animals (rats = rabbits greater than dogs). However, in dogs, the promoting effect of MCG on the rectal absorption of CMZ increased by addition of nonionic surfactants such as ether-type (Brij 30 and Brij 35) and ester type (Nikkol MYL-10). And the promoting effect of surfactants in the MCG vehicle is not always correlated with blood hemolysis, suggesting contribution of other physicochemical or biological factors.

Ventromedial thalamic lesions and seizure susceptibility

Recent data indicate that the substantia nigra is an important site in a circuitry involved in the modification of various experimental seizures with neocortical and limbic involvement. Since there are no direct nigral projections to either area, we assumed that the nigral effects on seizures are relayed by other sites such as the thalamus. To evaluate this hypothesis we produced bilateral high-radiofrequency thermocoagulative lesions of the ventromedial (VM) thalamic nuclei which receive the nigral efferents in the rat. We determined the susceptibility of lesioned and control adult rats to the development of flurothyl seizures 2 and 4 weeks later. The latency to the onset of a generalized seizure was considered as the convulsive threshold. There were no differences in the mean latencies between the groups. The results suggest that bilateral destruction of the VM thalamic nuclei does not modify the susceptibility to the development of flurothyl seizures in the rat.

Comparison of three semiautomatic methods for determination of left ventricular ejection fraction from gated cardiac blood pool images

A number of computer programs exist for the determination of ejection fraction from gated blood pool images. Three commercially available algorithms were compared on the same radionuclide data from 50 catheterized patients. The methods used were: (1) simple thresholding, (2) second derivative edge determination, and (3) a combination of these two. There was good correlation with catheterization ejection fraction for all three methods using smoothed data [r = 0.781, 0.77, 0.84 respectively (P less than 0.01)]. However, interobserver variance was significantly decreased (P less than 0.01) by use of the second derivative method when compared with the other two methods and catheterization. Thus, if accuracy and low interobserver variance are required, then a combination of a second derivative and thresholding method is preferable.

The synthesis and evaluation of radioiodinated 14-(iodophenyl)-3-(R,S)methyltetradecanoic acid

Radiohalogenated fatty acids (FA) labelled with gamma-emitting isotopes have a potentially important application in studies of impaired myocardial perfusion and metabolism. Evaluation of straight-chain fatty acids radiolabelled in different positions on the FA chain has been reported by many groups. In this paper we extended our recent studies using the betamethyl branched-chain fatty acid. The synthesis, labelling and preliminary evaluation of 131I- and 123I-14-(iodophenyl)-3-(R,S)methyltetradecanoic acid (I-PBMTA) are reported. This radiolabel concentrates in the mouse myocardium with 16% injected dose g-1 and 11% injected dose g-1 at 15 and 30 min, respectively. The images of the canine heart postinjection indicate a high myocardial extraction of the label with activity retained over an hour. The rate of washout of the activity from the heart was very low. This analogue is a potential agent for myocardial imaging studies.

Improvement of bioavailability of poorly absorbed drugs. II. Effect of medium chain glyceride base on the intestinal absorption of cefmetazole sodium in rats and dogs

The effect of medium chain glyceride (MCG) on the intestinal absorption of cefmetazole sodium (CMZ) was investigated in rats and dogs. In rats, MCG containing glyceryl mono-, di- and tri-caprylate enhanced the intestinal absorption of CMZ after intraduodenal administration, though the promoting effect of MCG was less than that after rectal administration. The promoting effect of MCG was found to be mainly due to glycerylmonocaprylate and dependent on the dosage of MCG. The plasma CMZ levels after intraduodenal administration as MCG solution tended to be slightly higher than those observed after administration as MCG emulsion, though the differences were found to be statistically insignificant. Moreover, the intestinal absorption of CMZ after intraduodenal administration as MCG emulsion was decreased significantly by increasing the amount of water in the emulsion. The promoting effect of MCG in dogs was more clearly demonstrated in the lower intestine than in the upper intestine. Furthermore, the oral bioavailability of pharmaceutical formulations of CMZ was also investigated in dogs. When enteric coated capsules filled with MCG solution were administered to dogs, the bioavailability of CMZ was enhanced significantly.

[Traumatic mitral insufficiency: a case report]

A 25-year-old man was admitted to Juntendo University Hospital with chief complaints of nocturnal dyspnea and shortness of breath on Sept. 22, 1983. He had no history of rheumatic fever or bacterial endocarditis. He was violently kicked in the chest while practicing Shorinji-Kempo (Karate) in July 1977. His heart murmur was first noticed in April 1978, but he was asymptomatic for six years after the accident until transient nocturnal dyspnea developed January 1983. Physical examination on admission revealed a grade 4/6 apical holosystolic murmur, a markedly accentuated third sound, and hepatomegaly of two finger breadth in the right midclavicular line. An electrocardiogram revealed sinus tachycardia (100/min), left atrial overload and left ventricular hypertrophy. Chest radiography showed slight cardiac enlargement with a cardiothoracic ratio of 55%, and slightly increased pulmonary vascular markings. Two-dimensional echocardiography showed a markedly prolapsed posterior mitral leaflet and fluttering in diastole. Cardiac catheterization showed elevated pressure of pulmonary capillaries (a: 16, v: 30, mean: 19 mmHg), the pulmonary artery and the right ventricle. Left ventriculography revealed grade four (Sellers) mitral regurgitation. Mitral valve replacement was performed on October 13, 1983. A chorda tendinae supporting the posterior leaflet of the mitral valve was found to be ruptured just above its origin from the posterior papillary muscle. Histological examination of the resected valve showed increased spongiosa tissue which mimicked so-called myxomatous changes, but it seemed preferable to interpret this as a "secondary change due to increased hemodynamic stress" rather than the "primary change".

Myocarditis in autopsy

In the Annuals of Autopsy Records for Japan from 1958 to 1977, 377,841 autopsy cases were registered; a short summary of pathologic findings was included. Of the 377,841 cases, 409 (0.11%) were registered as idiopathic, nonspecific, interstitial, or viral myocarditis and 25 cases (0.007%) as giant-cell myocarditis. The annual incidence of the myocarditis varied at 5-year intervals and a remarkable increase was observed after 1974. An analysis of 19 cases of myocarditis and 19 of postmyocarditic cardiomegaly (PMC) showed a preponderance of males. Dilatation of ventricles was found in all cases of acute, subacute, and healing myocarditis, which histologically showed interstitial mononuclear cell infiltration, necrosis, and disarray of myocytes. Hypertrophy with ventricular dilatation, ventricular dilatation without hypertrophy, endo- or epicardial involvement, and right ventricular lipomatosis were found in 70%, 20%, 30%, and 10% of cases with chronic myocarditis and PMC, respectively. In these cases, residual inflammation, fibrosis, and hypertrophy was observed histologically.

Improvement of bioavailability of poorly absorbed drugs. I. Effect of medium chain glyceride base on the rectal absorption of cefmetazole sodium in rats

The effect of medium chain glyceride on the rectal absorption of cefmetazole sodium is investigated using an in situ experiment in rats. Each glyceride component of medium chain glyceride was separated using a high-performance liquid chromatographic method. The promoting effect of medium chain glyceride was found to be mainly due to glycerylmonocaprylate and dependent on the concentration of glycerylmonocaprylate. When cefmetazole sodium in medium chain glyceride solution was administered into the rectal lumen of rats, rapid absorption of the drug was observed leading to a residual amount of about 45% at 15 min after administration. The promoting effect of medium chain glyceride was found to be more effective in the rectum than in the small intestine.

An autopsy case of rheumatoid arthritis with aortic steno-insufficiency, angina pectoris and severe heart failure

Although nonspecific pericarditis, myocarditis, valvulitis, and coronary arteritis are known as cardiac lesions that accompany rheumatoid arthritis (RA), there have been few reports of the occurrence of clinically severe valvular disease. We report here the case of 69-year-old man with a 25-year history of RA who died of acute left-sided heart failure complicating to aortic steno-insufficiency and angina pectoris. Autopsy findings revealed the coincidence of a congenital bicuspid aortic valve with chronic inflammation, fibrosis and calcification; eccentric hypertrophy and myocardial fibrosis of the left ventricle; 75% luminal narrowing of the proximal portion of the coronary artery due to atherosclerosis, and narrowing of the small arteries of the cardiac muscle due to angitis. It is deduced that the coronary artery lesions, aortic valve lesions and myocardial lesions were aggravated by the bicuspid aortic valve, changes with ageing and corticosteroid therapy.

Infantile status epilepticus and future seizure susceptibility in the rat

The long-term effects of infantile seizures on the development of seizures in adulthood were studied in rats. Infantile seizures of varying severity were induced with intraperitoneal injections of kainic acid in 15-day-old rats. In adulthood the seizure susceptibility of the rats was determined by kindling the left amygdala and by measuring their ability to resist recurrent seizures. The results suggest that infantile status epilepticus is associated with a very high mortality; however in the surviving rats, infantile seizures even as severe as status epilepticus do not cause neuronal brain damage and do not predispose to the development of convulsions later in life.

A morphometrical study of myocardial disarray associated with right ventricular outflow tract obstruction

In order to define quantitatively the histological characteristics of the hypertrophied myocardium of the right ventricular outflow tract in patients with congenital heart disease, a light-microscopic study of biopsy specimens obtained from 20 cases with tetralogy of Fallot (TOF) and 14 cases with muscular obstruction of the right ventricular outflow tract ( RVOTO ) was performed using a semi-automatic sampling counter. As the controls, the crista supraventricularis of 11 autopsied cases without cardiac disease were used. The TOF patients were divided into two groups: those with (9 cases) or without (11) a history of hypoxic spells. The myocyte diameter was calculated according to Chalkley 's and Arai 's method. The areas of myocardial fibrosis and myocyte disarray were determined quantitatively by the point count method. Myocardial fibrosis was classified into five types: focal, mild perimysial, severe perimysial, perivascular and plexiform. In the control group, the myocyte diameter and area of fibrosis and disarray tended to increase with age. In the obstructive groups, the myocyte diameter and area of disarray were greater than those of the control in any age group. Myocyte diameter tended to increase with age in all groups, except for the TOF cases with a history of hypoxic spells. The latter also had the largest area of myocardial disarray (25.3%) (p less than 0.01), and a largest area of fibrosis (20.5%) than the TOF cases without spell (14.4%), but severe perimysial fibrosis was observed in only five out of the nine patients with spells. The lack of a relation between the pressure and the presence of an increased area of the myocardial disarray in TOF with spells implies that this myocardial change is brought about by myocardial abnormality accompanied by cardiac malformation.

Successful surgical ablation of reentrant ventricular tachycardia caused by myocardial fibroma

We successfully removed a fibroma of the left ventricle in a 13-year-old boy. The tumor had caused recurrent ventricular tachycardia, which was resistant to antiarrhythmic drugs. Preoperative and intraoperative electrophysiological studies led to a diagnosis of reentrant ventricular tachycardia. After surgical excision of the tumor, the ventricular tachycardia stopped completely and until now, 1 year after the operation, no antiarrhythmic drugs have been required.

Kainic-acid-induced seizures: a developmental study

Developmental dose-response curves for kainic-acid-induced seizures were generated in rats. Rats at 15-18 days (pups), 33-37 days ( pubescents ) and over 90 days (adults) were administered kainic acid intraperitoneally. Seizures were elicited in all 3 age groups, but some of the behavioral manifestations differed in the pups. This group also had the lowest convulsive threshold, the most severe seizures and the highest mortality. Forelimb convulsions and status epilepticus were associated with the occurrence of necrotic lesions in the adults and pubescents but not in the pups. Deoxyglucose (DG) autoradiographic studies of the convulsing rats disclosed differences in the DG uptake pattern of the substantia nigra across the 3 age groups. Increases in the DG uptake were present in the two older age groups but not in the pups. Since recent data have implicated the substantia nigra as a crucial site in a seizure modifying circuitry in adult animals, our results suggest that the lack of substantia nigra involvement in the pups may account for the early generalization and the increased severity of seizures in this age group.

Histopathological correlation between the QRS axis and disposition of the atrioventricular conduction system in common atrioventricular orifice and in its related anomalies

Serial sections of the atrioventricular (AV) conduction system were microscopically studied in 12 autopsied hearts: four with complete type common AV orifice (CAVO), two with atrial septal defect of the ostium primum type (ASD-I), two with ventricular septal defect of the persistent common AV canal type (VSD-C) and four without heart disease. The anatomic findings were semiquantitatively compared with the normal control using Feldt's method and correlated to the mean frontal QRS axis on ECG. The cases of CAVO or VSD-C with left axis devation invariably showed similar patterns regarding the location and course of the AV conduction system: (1) posterior displacement of the AV node, (2) relatively short distance between the AV node and the beginning of the left bundle branch (LBB), and (3) postero-inferior displacement of the bundle of His and the LBB. The postero-inferior displacement of the LBB seemed to be responsible for left axis deviation. The cases of ASD-I showed some additional findings: (1) impaired contiguity between the AV node and the bundle of His might have caused the occasional advanced AV block in one case, and (2) the posterior radiation of the LBB traversed down through the branch-free muscle bundle, which was assumed to be related to the right axis deviation in the other case. These findings suggest that the disposition of the AV conduction system in CAVO and in its related anomalies were basically the same whatever the type of defect, and this was considered to be correlated to the established ECG pattern.

An autopsied case of a two-month-old infant with granulomatous pancarditis having severe vasculitis and valvulitis

A 2-month-old female infant with pancarditis was reported. The patient died after a 26-day clinical course. The autopsy showed pancarditis, including inflammation in all 4 valves and chordae, fibrinoid vasculitis, pharyngolaryngitis and atrophy of the lymph nodes. Microscopic examination revealed proliferative inflammation in the endocardium, valve, myocardium, epicardium and coronary vessels. The histological findings suggested the etiology to be a rheumatic-type reaction at an extremely young age.

The location and course of the atrioventricular conduction system in common atrioventricular orifice and in its related anomalies with transposition of the great arteries--A histopathological study of six cases

The location and course of the atrioventricular (AV) conduction system were studied histopathologically in 6 hearts by sectioning serially, 4 having common AV orifice (CAVO) with complete or partial transposition of the great arteries (TGA) and 2 having ventricular septal defect of the persistent common AV canal type (VSD-C) with complete TGA. Two cases of CAVO with TGA and asplenia syndrome (Cases 1 and 2) had 2 discrete AV conduction systems, being posterior and anterior to the site of the defect, respectively. In these 2 cases posterior AV conduction system well developed, whereas the anterior one was hypoplastic. In another case of CAVO with TGA and asplenia syndrome (Case 3), only the anterior AV conduction system existed near the base of the great arteries. In the other case of CAVO with TGA and polysplenia syndrome (Case 4), the posterior AV conduction system was found to have a congenital interruption of the AV bundle of His. Two cases of VSD-C with TGA but with no splenic anomaly (Cases 5 and 6) showed the posterior AV conduction system with communication-free accessory bundles. The posterior AV node, bundle of His and left bundle branch inevitably shifted postero-inferiorly, except in Case 3. The bundle branches were always distributed appropriately to their morphologically matched ventricles. The superiorly oriented vector in the mean frontal QRS axis in Cases 1, 5 and 6 seemed to be related to the postero-inferior displacement of the posterior AV conduction system, whereas those of the left-inferior oriented vector in Cases 2 and 3 were thought to be responsible for the excessively unbalanced size of ventricles. The complete AV block in Case 4 was correlated with the interruption of the bundle of His. The morphogenesis of the anterior AV conduction system was discussed in relation to the asplenia syndrome.