[Effects of high carbohydrate and high fat diet on plasma apolipoproteins AI, AII, B100, CI, CII, CIII and E in normal and hypertriglyceridemic humans]

Effects of high carbohydrate (CHO) and high fat diet on plasma apolipoproteins (apo) AI, AII, B100, CI, CII, CIII and E were assessed in 10 healthy subjects and 10 patients with endogenous hypertriglyceridemia. High CHO diet consisted of 80% CHO, 5% fat and 15% protein of total calories, and high fat diet consisted of 40% CHO, 45% fat and 15% protein. After 5 days normal diet (60% of total calories from CHO, 25% from from fat and 15% from protein), the subjects studied received sequentially high CHO diet and normal diet for 5 days and high fat diet and normal diet for 5 days. Fasting blood samples were drawn on days 1, 3, and 5 of high CHO and high fat diet period, and 5 days after taking normal diet. Results showed that fasting plasma apo AI slightly decreased (P less than 0.01) on day 3 of the high CHO diet period and slightly increased (P less than 0.01) on day 3 of the high fat diet period, plasma apo AII increased after intake of high CHO diet, but no changes were observed after the subjects were placed on high fat diet. Fasting plasma apo B100 decreased (P less than 0.001) in hypertriglyceridemics on the 3rd day of the high CHO diet, but no differences were noted in normal subjects on the same diet. On the 3rd day of the high fat diet period, apo B100 increased (P less than 0.01) in normal subjects, but no changes were found in hypertriglyceridemics. Apo CII and CIII levels declined during the high CHO diet period but increased in normal subjects after intake of high fat died.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of laminin B1 mRNA in retinal ganglion cells by in situ hybridization

In the nervous system, neuronal migration and axonal growth are dependent on specific interactions with extracellular matrix proteins. During development of the vertebrate retina, ganglion cell axons extend along the internal limiting (basement) membrane and form the optic nerve. Laminin, a major component of basement membranes, is known to be present in the internal limiting membrane, and might be involved in the growth of ganglion cell axons. The identity of the cells that produce retinal laminin, however, has not been established. In the present study, we have used in situ hybridization to localize the sites of laminin B1 mRNA synthesis in the developing mouse retina. Our results show that there are at least two principal sites of laminin B1 mRNA synthesis: (a) the hyaloid vessels and the lens during the period of major axonal outgrowth, and (b) the retinal ganglion cells at later development stages. Müller (glial) cells, the major class of nonneuronal cells in the retina, do not appear to express laminin B1 mRNA either during development or in the adult retina. In Northern blots, we found a single transcript of approximately 6-kb size that encodes the laminin B1 chain in the retina. Moreover, laminin B1 mRNA level was four- to fivefold higher in the postnatal retina compared to that in the adult. Our results show that in addition to nonneuronal cells, retinal ganglion cells also synthesize laminin. The function of laminin in postnatal retinas, however, remains to be elucidated. Nevertheless, our findings raise the possibility that neurons in other parts of the nervous system might also synthesize extracellular matrix proteins.

Figure-eight kinking of the aorta (pseudocoarctation) coexistent with coarctation

An asymptomatic young man presented with a cardiac murmur and hypertension only in the right arm. Angiograms showed kinking of the aortic arch with a figure-eight appearance consistent with pseudocoarctation. Before the kinked segment, also demonstrated were a stenotic lesion in the aortic arch proximal to the left carotid artery and profound collateral circulations in the right thorax. These findings strongly suggested a rare combination of pseudocoarctation and true coarctation. His hypertension was corrected following surgery with a bypass graft between the ascending aorta and the abdominal aorta.

Atrial natriuretic peptide and vasopressin during percutaneous transvenous mitral valvuloplasty and relation to renin-angiotensin-aldosterone system and renal function

To study the relation between plasma atrial natriuretic peptide (ANP) and cardiac pressure, and to assess the pathophysiologic significance of ANP in water and electrolyte metabolism, the changes in plasma levels of ANP and arginine vasopressin (AVP) were examined in 11 patients with mitral stenosis who underwent percutaneous transvenous mitral valvuloplasty, and compared with the changes in the renin-angiotensin-aldosterone system and renal function. Immediately after valvuloplasty, plasma ANP levels decreased significantly with a concomitant decrease in mean pressures in the left atrium, the pulmonary artery and the right atrium. Plasma ANP levels decreased to the normal range in 4 of the 6 patients with normal sinus rhythm, while all 5 patients with atrial fibrillation had higher levels despite a similar degree of decrease in atrial pressure. There were significant positive correlations between plasma ANP levels and the mean left atrial pressure (r = 0.61, p less than 0.01), the mean pulmonary arterial pressure (r = 0.49, p less than 0.01) and the mean right atrial pressure (r = 0.54, p less than 0.01). The mean plasma AVP levels, on the other hand, showed a transient increase after valvuloplasty from 0.5 +/- 0.1 to 1.2 +/- 0.4 pg/ml (p less than 0.05). The mean plasma renin activity (1.3 +/- 0.3 vs 2.7 +/- 0.8 ng/ml/hr, p less than 0.05) and plasma aldosterone concentration (8.6 +/- 2.3 vs 17.2 +/- 5.2 ng/dl, p less than 0.05) also increased significantly 30 minutes after valvuloplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic and clinical efficacies of catheter balloon percutaneous transvenous mitral commissurotomy: experience of 100 patients with rheumatic mitral stenosis

From January 1987 to December 1988, 100 patients with symptomatic severe rheumatic mitral stenosis underwent percutaneous transvenous mitral commissurotomy (PTMC). The patients included 32 males and 68 females, aged 19-71 years (mean of 41). Mild mitral regurgitation (grade 1 or 2) was present in 23 patients and a history of thromboembolism in 12. One patient had had mitral restenosis after surgical open mitral commissurotomy 9 years earlier. The mitral valve was successfully dilated in 97 patients. PTMC resulted in immediate improvements in hemodynamic measurements. The left atrial pressure decreased from 24.5 +/- 5.3 to 14.8 +/- 5.2 mmHg (p less than 0.001), the mean mitral transvalvular gradient from 13.8 +/- 4.8 to 5.0 +/- 2.8 mmHg (p less than 0.001), and the mean pulmonary artery pressure from 38.8 +/- 12.0 to 30.6 +/- 10.3 mmHg (p less than 0.001). The mitral valve area increased from 1.1 +/- 0.3 to 2.2 +/- 0.8 cm2 (p less than 0.001). The cardiac output increased from 4.5 +/- 1.2 to 4.84 +/- 1.2 L/min (p less than 0.05). The right atrial pressure did not change significantly after PTMC (6.5 +/- 3.8 vs 6.4 +/- 4.0 mmHg). The mitral valve area measured by 2-D echocardiograms increased from 1.04 +/- 0.48 to 1.88 +/- 0.66 cm2 after PTMC (p less than 0.001). All 97 patients were followed for 6-24 months (median of 13) after the PTMC. After an initial recovery period of 1-2 weeks, all patients reported improvements in symptoms and in New York Heart Association (NYHA) functional class by at least one class. A comparison between treadmill exercise test durations before, and 3 months after PTMC, showed an increase from 9.1 +/- 4.3 to 15.4 +/- 3.8 minutes (n = 60; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of L-glutamic acid decarboxylase mRNA in cat retinal horizontal cells by in situ hybridization

Retinal horizontal cells receive synaptic input from photoreceptors and provide a pathway for lateral interactions in the vertebrate retina. In nonmammalian retinas, the H1 horizontal cells appear to use gamma-amino butyric acid (GABA) as their neurotransmitter. The transmitter used by mammalian horizontal cells, however, remains to be identified. In the present study, we have employed in situ hybridization to examine whether cat retinal horizontal cells contain L-glutamic acid decarboxylase (GAD) mRNA and hence might use GABA as their transmitter. In the cat retina, labeled cell bodies were found in the inner nuclear layer and the ganglion cell layer. No labeled cells were found in the photoreceptor layer. In the inner nuclear layer, labeled somata were present at two locations. The majority of them (approximately 72%) were located in the vitread side of the inner nuclear layer bordering the inner nuclear layer/inner plexiform layer boundary. A second class of labeled cells in the inner nuclear layer (approximately 20%) had larger somata and were present at the inner nuclear layer/outer plexiform layer boundary. Double labeling experiments with antisera to parvalbumin, a horizontal cell marker, showed that these perikarya belonged to horizontal cells. RNA blot analysis showed that cat retina contains a single species of GAD mRNA that is about 4 kb in size. These data show that in addition to GABAergic amacrine, displaced amacrine, and interplexiform cells described previously, horizontal cells contain GAD mRNA and may use GABA as their neurotransmitter. Hence, GABA may be a transmitter that is involved in lateral inhibition in both nonmammalian and mammalian retinas.

Localization of L-glutamic acid decarboxylase mRNA in monkey and human retina by in situ hybridization

Immunocytochemical studies with gamma-aminobutyric acid (GABA) antibodies and glutamic acid decarboxylase antibodies have shown that the primate retina contains GABAergic amacrine, interplexiform, and displaced amacrine cells. In addition, subpopulations of photoreceptors and horizontal cells have also been suggested to be GABAergic in this retina. In the present study, we have used in situ hybridization to localize GABAergic neurons in human and monkey retinas. In situ hybridizations were carried out with 35S-labeled DNA and RNA probes derived from human and cat glutamic acid decarboxylase cDNA clones. In the monkey retina, labeled cells were present in the inner nuclear and ganglion cells layers. The outer nuclear layer or the inner segment layer had only background levels of labeling. In the inner nuclear layer, all labeled somata were located in the vitread-half bordering the inner nuclear layer/inner plexiform layer boundary. These cells constituted approximately 83% of all labeled cells. Labeled cells were also seen in the ganglion cell layer. In the human retina, labeled somata were observed only in the inner nuclear and the ganglion cell layers. In the inner nuclear layer, the majority of labeled cells were located close to the inner nuclear layer/inner plexiform layer boundary although a minor population of labeled somata (approximately 20%) were found deeper in the inner nuclear layer. The distribution of glutamic acid decarboxylase mRNA-containing cells we observed is in good agreement with the known location of GABAergic neurons. We, however, did not find glutamic acid decarboxylase mRNA in either horizontal cells or photoreceptors in monkey and human retina.

Subcellular localization of an intermediate filament protein and its mRNA in glial cells

Eucaryotic mRNAs are generally localized in the cell body, where most protein synthesis occurs. We have found that mRNAs encoding the glial intermediate filament protein are spatially distributed in the glial cell cytoplasm close to the location of the glial filaments. Whereas the glial filament protein mRNA was located predominantly in the distal process, actin mRNA was found almost exclusively in the apical portion of the glial cell. This pattern of mRNA localization might provide a mechanism for synthesis of proteins in specific subcellular compartments by mRNA translation locally.

Transcriptional activation of an intermediate filament protein gene in mice with retinal dystrophy

We are interested in understanding neuronal interactions that regulate expression of specific genes in glial cells in the nervous system. In the normal mouse retina, the glial intermediate filament protein (GFAP) is not detectable in Müller cells, the predominant glial cells in the retina. Photoreceptor degeneration resulting from retinal degeneration (rd) mutation or environmental light damage, however, leads to the appearance of GFAP in Müller cells. We have investigated the mechanism underlying GFAP accumulation in these retinas. Western blotting analysis, steady-state mRNA level comparisons, and nuclear run-on assays show that transcription of the GFAP gene is activated in these retinas. In situ hybridizations with retinal sections and solitary Müller cells establish that GFAP mRNA levels are elevated in Müller cells. These results show that disruption of neuron-glia interactions resulting from photoreceptor degeneration leads to activation of the GFAP gene in glial cells of mice with retinal dystrophy. The functional significance of this glial response and the need for GFAP expression remain to be understood.

Rapid fall in elevated plasma atrial natriuretic peptide levels after successful catheter balloon valvuloplasty of mitral stenosis

To determine whether an acute fall in atrial pressure decreases the secretion of atrial natriuretic peptide in man, changes in the plasma levels of this peptide were studied after catheter balloon valvuloplasty of the mitral valve. Ten patients with severe mitral stenosis were included in the study. The valvuloplasty resulted in an immediate reduction in left atrial pressure and an increase in the mitral valve area. Decreases in right atrial pressure were inconsistent and less significant. Plasma atrial natriuretic peptide levels, which were elevated before the valvuloplasty, decreased significantly in all 10 patients at 15 minutes after the valvuloplasty and reached lower plateaus at 30, 45, and 60 minutes after the procedure. In the seven patients studied for a longer period, both plasma atrial natriuretic peptide levels and the left atrial pressure remained reduced 24 hours after the valvuloplasty. Plasma atrial natriuretic peptide levels before and 30 to 60 minutes after the valvuloplasty were positively correlated to simultaneously determined left and right atrial pressures. These results indicate that atrial stretch caused by increased atrial pressure is an important stimulus for atrial natriuretic peptide release in man. "De-stretching" of the myocytes of the atria results in rapid inhibition of atrial natriuretic peptide secretion.

Early diagnosis of acute myocardial infarction by myoglobin latex agglutination test

Early elevation of the serum myoglobin level in acute myocardial infarction (AMI) has been noted for years. In this study, 39 patients admitted to the Coronary Care Unit with acute chest pain within 72 hours (mean 12 +/- 15 hours) or electrocardiographic changes suspected of acute myocardial infarction had a serum myoglobin latex agglutination test to evaluate its diagnostic accuracy in acute myocardial infarction. Of these 39 patients, 24 had documented acute myocardial infarction as their final diagnosis. By the time of admission, 18 of the 24 cases with infarction had positive myoglobin tests (sensitivity 75%). Of those 15 cases without myocardial infarction, 13 had negative myoglobin tests (specificity 87%). If only those 17 cases admitted within 5 hours of the onset of chest pain were analyzed, the serum myoglobin test became positive in 8 of 10 cases with documented AMI but the 2 cases with negative results turned positive 2 hours later (sensitivity 80% to 100%). Due to the fact that myoglobin tests were negative in all other 7 cases without infarction, the specificity was 7/7 (100%). In contrast, the creatine phosphokinase isoenzyme study was positive only in 3 of these 10 patients with documented AMI in the first blood sample taken during admission. In conclusion, the serum myoglobin latex agglutination test is a quick and reliable method that helps in the early diagnosis of acute myocardial infarction.

Doppler atrial shunt flow patterns in patients with secundum atrial septal defect: determinants, limitations, and pitfalls

Fifteen patients with uncomplicated secundum atrial septal defect underwent studies with real-time color-coded two dimensional flow imaging, pulsed Doppler echocardiographic examination, and simultaneous pressure recordings from the left and right atrium to determine the flow-pressure dynamics of the atrial shunt flow. In all 15 patients both the color flow mapping and pulsed Doppler studies revealed that the shunt flow was mainly from left to right, occurring both during ventricular systole and diastole. It started in early systole, reached a peak in late systole to early diastole, and lasted throughout diastole with an accentuation in late diastole during atrial contraction. The amplitude of the flow velocity, the direction, and the magnitude of the shunt flow, however, changed from phase to phase during the cardiac cycle. It correlated well with the phasic variation of the interatrial pressure difference, which usually revealed a peak pressure gradient that occurred in early systole between the x descent and v wave and during the period of v wave and a wave of the left atrial pressure tracing. Right to left shunt was not detected in any of the 15 patients by color flow mapping studies. A minor reversal of the shunt flow, however, was frequently detected at the beginning of ventricular systole and sometimes also in the middle of diastole by pulsed Doppler echocardiography. The reversal of shunt flow correlated with the minor reversal of pressure gradient that occurred during the z point, x descent, and y descent of the left atrial pressure tracing. In conclusion, left to right shunt flow occurs both during ventricular systole and diastole in uncomplicated secundum atrial septal defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolated right-sided patent ductus arteriosus in right-sided aortic arch. Report of two cases

An isolated right-sided patent ductus arteriosus has not been reported previously to occur in right-sided aortic arch associated with an aberrant left subclavian artery. We report such anomalies in two adult patients. In the first case of a 19-year-old woman, the ductus was successfully ligated via a left posterolateral thoracotomy; however, many technical difficulties were encountered. In the second case of a 36-year old woman, a right posterolateral thoracotomy enabled detailed demonstration of the ductus and its surrounding structures and facilitated its successful ligation. An isolated right-sided patent ductus arteriosus should be approached via right thoracotomy.

Pharmacokinetics and pharmacodynamic effects of aqueous diltiazem in healthy humans

Aqueous diltiazem was given to ten healthy male volunteers in a single oral dose of 2.5 mg/kg body weight. Serum diltiazem levels were measured at various intervals up to 24 hours after administration of the drug as were blood pressure, heart rate, and PR interval. The pharmacokinetics followed a one-compartment model in six and two-compartment model in four subjects. The mean distribution half-life in the latter four subjects was 15.8 +/- 3.7 minutes (range, 10.4-18.8 min). In the ten subjects, the peak serum diltiazem level was attained in 20 to 45 minutes (mean, 32.5 +/- 9.5 min) and ranged from 136 to 701 ng/mL (mean, 332 +/- 180 ng/mL). The elimination half-life ranged from 2.8 to 4.8 hours (mean, 3.8 +/- 0.6 hr). The area under the concentration-time curve varied from 508 to 2,245 ng-hr/mL, indicating differing bioavailability. Slight but significant blood pressure reduction was seen only at one to three hours. Changes in heart rate were not significant at any measurement. Transient facial flushing, beginning at ten to 20 minutes after administration, was noted in nine subjects, reflecting the vasodilatory effect of the drug. Significant prolongation (greater than 10%) of PR intervals began at ten minutes in three, at 20 minutes in six, and at 30 minutes in one participant, and progressed to second-degree Wenckebach atrioventricular (AV) block in six subjects 20 to 60 minutes after administration and third-degree AV block in one person 45 minutes after dosing. These AV blocks resolved by the third hour without treatment, and PR prolongation resolved by the fifth to seventh hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of adequate gas-mixing in contrast echocardiography

Microbubble formation has been accepted as the mechanism producing contrast echoes. Comparisons of the contrast effects of various agents have been studied extensively, but the importance of gas-mixing has been less appreciated. To test the hypothesis that good gas-mixing, by facilitating microbubble formation, would enhance contrast effect, this study compared the contrast echocardiograms of ten adult patients before and after mixing carbon dioxide with various contrast agents. Contrast agents tested included a 5 percent glucose in water, vitamin B complex, vitamin C, and Cardiogreen solutions. First, we recorded echocardiograms by injecting each diluted contrast solution alone, then repeated the examinations using 10 ml of each diluted solution with 1 ml of carbon dioxide (CO2), mixed by means of a four-way stopcock. Satisfactory or excellent results were obtained in seven of ten, ten of ten, ten of ten, and ten of ten tests, respectively, after thorough gas-mixing, vs one of ten, seven of ten, eight of ten, and six of ten, respectively, before gas-mixing. We conclude that the addition of sufficient amounts of gas, followed by thorough mixing, is of great importance in contrast echocardiography. Consistently good results can be achieved with vitamin C, vitamin B or Cardiogreen solutions by this simple and safe method.

Paroxysmal supraventricular tachycardia initiated by a swallowing-induced premature atrial beat

We report a unique patient in whom electrophysiologic studies elucidated the mechanism of a rare form of swallowing-induced atrioventricular reentrant tachycardia, and for whom successful surgical ablation of an accessory pathway abolished intractable episodes of palpitation. A 64-year-old man was incapacitated by frequent attacks of palpitation following swallowing. Electrocardiograms documented paroxysmal supraventricular tachycardias initiated by a premature atrial beat or beats following swallowing. During electrophysiologic studies swallowing consistently induced premature atrial beats which in turn initiated a sustained atrioventricular reentrant tachycardia incorporating a retrogradely conducting left-sided concealed accessory pathway. The atrial activation sequence related to the premature atrial beats and the morphology of the premature P waves suggested that premature atrial beats originated in the right atrium. The mechanism of induction of premature atrial beats following swallowing remains obscure in our patient. Antiarrythmic drugs failed to prevent induction of sustained tachycardias during sequential electrophysiologic studies. The patient underwent successful surgical ablation of the accessory pathway and is free from palpitation 15 months after the surgery.

Serial electrophysiologic studies of the effects of oral diltiazem on paroxysmal supraventricular tachycardia

In 16 patients with paroxysmal supraventricular tachycardia, electrophysiologic studies were done before and serially at hourly intervals for eight hours after the third oral dose of 90 mg diltiazem given every eight hours. Diltiazem increased both the longest atrial paced cycle length producing type 1 atrioventricular block and the effective refractory period of the atrioventricular conducting system at all measurements. Before diltiazem, all 16 patients had induction of sustained tachycardia. After diltiazem, sustained tachycardia could not be induced in ten patients at any measurements; in these patients, either echo or nonsustained tachycardia was induced. In the remaining six patients, sustained tachycardia was induced, particularly after six hours. Follow-up observations in 12 patients receiving the same dosage of oral diltiazem for 6 +/- 2 months (mean +/- SD), showed that of the eight patients in whom electrophysiologic testing induced either echo or nonsustained tachycardia, six were asymptomatic and two experienced transient palpitation. Of the other four patients with induction of sustained tachycardia, three had transient palpitation and one had occasional attacks of sustained tachycardia requiring modification of therapy. Thus, oral diltiazem increases atrioventricular nodal refractoriness, with an effect lasting up to eight hours. It is an effective agent for the prophylaxis of paroxysmal supraventricular tachycardia.

Usefulness of intravenous diltiazem in predicting subsequent electrophysiologic and clinical responses to oral diltiazem

Diltiazem, 0.25 mg/kg, was given intravenously during induced tachycardias in 6 patients with atrioventricular (AV) nodal reentrant tachycardia (group I) and in 24 patients with AV reentrant tachycardia incorporating a retrogradely conducting accessory pathway (group II). In all 6 group I and in 15 of 24 group II patients, tachycardias terminated within 1 minute after diltiazem administration, with a weak link in the anterograde direction. In 3 other patients in group II, tachycardias were terminated by a premature ventricular complex within 1 minute. In the remaining 6 patients in group II, in whom tachycardias failed to terminate, rates of tachycardias decreased as a result of suppression of anterograde AV nodal conduction by diltiazem. Electrophysiologic studies were performed subsequently 2 hours after the third dose of 90 mg of diltiazem, which was given orally at 8-hour intervals. In 18 responders to intravenous diltiazem who were subjected to oral diltiazem testing, sustained supraventricular tachycardia (SVT) could be induced in only 2. Of the 6 nonresponders, sustained tachycardias could not be induced in 3. Twelve patients, including 11 responders and 1 nonresponder to intravenous diltiazem who responded to oral diltiazem testing, were discharged with oral diltiazem therapy, 90 mg every 8 hours, with follow-up periods of 2 to 13 months (mean 7 +/- 4 [+/- standard deviation]). The frequency of recurrent SVT decreased significantly; 8 patients were free of tachycardias and 4 had occasional recurrences of SVT that required no hospital visit. In conclusion, intravenous diltiazem is effective in terminating SVT. Termination of SVT by intravenous diltiazem predicts subsequent electrophysiologic and clinical responses to oral diltiazem.

THE INTERNAL STRUCTURE OF THE ELK KELP (PELAGOPHYCUS SPECIES)

A comparative anatomical study of two species of Pelagophycus has revealed specific differences in the nuclear volumes of meristoderm cells, morphology and branching of mucilage ducts, and medulla construction in the solid stipes. Pelagophycus spp. have nucleate sieve elements in all organs except the holdfast. Mucilage ducts and multinucleate cortical cells occur throughout the thallus. These and other features demonstrate that Pelagophycus is closely related to and probably phyletically intermediate between Macrocystis and Nereocystis.