Ultrastructural responses by Golgi apparatus of rat submandibular gland to beta-adrenergic, alpha-adrenergic, and cholinergic stimulation

Rat submandibular gland tissue pieces were stimulated in vitro for 30 min with a beta-adrenergic agent or a cyclic AMP analog to stimulate protein secretion, or with alpha-adrenergic or cholinergic agents or a Ca2+ ionophore to stimulate fluid secretion. Acinar cells were examined by transmission electron microscopy. In control tissue, acinar cells showed little evidence of secretory activity. The Golgi apparatus was sparse and was associated with a few small, immature secretory granules with fine fibrillar contents. Following secretory granule discharge stimulated by isoproterenol or dibutyryl cyclic AMP, acinar cells were constricted, and had extensive basolateral membrane folding and tightly packed rough endoplasmic reticulum. Golgi complexes were prominent and had multiple small granules with filamentous contents. After stimulation of fluid secretion by alpha-adrenergic agents (epinephrine, phenylephrine), or cholinergic agents (acetylcholine, carbachol, pilocarpine), or a Ca2+ ionophore (A23187), the Golgi apparatus had compact concave cisternae enclosing aggregates of tubulovesicles. Acinar cells were distended, basolateral membranes were expanded, and rough endoplasmic reticulum was dilated and vesiculated.     

Abnormal left ventricular response to isometric exercise in pure, isolated aortic regurgitation: beneficial effects of nifedipine

To examine the effects of nifedipine on the left ventricular (LV) functional response to isometric exercise in patients with aortic regurgitation (AR), 20 patients with isolated, moderate to severe AR performed 3 minutes of handgrip exercise at 33% of their maximal voluntary contraction, before and after administration of 20 mg of sublingual nifedipine. Although handgrip exercise produced similar increases in heart rate and systolic blood pressure before and after nifedipine treatment, heart rate was higher and systolic blood pressure lower with handgrip exercise during nifedipine treatment. LV end-diastolic volume index was not different during the control period and nifedipine handgrip exercise, but the increase in end-systolic volume index was smaller and the ejection fraction was higher during nifedipine handgrip exercise. Nifedipine reduces afterload and ameliorates handgrip exercise-induced LV dysfunction in patients with AR.     

Influence of heart rate and atrial transport on left ventricular volume and function: relation to hemodynamic changes produced by supraventricular arrhythmia

The response of the left ventricle to pacing-induced changes in heart rate and the atrioventricular (A-V) relation was examined with equilibrium gated radionuclide ventriculography in 20 patients who had normal ventricular function after surgery for recurrent supraventricular tachycardia. In 10 patients count-derived left ventricular ejection fraction, end-diastolic volume and stroke volume were measured during sinus rhythm and during atrial pacing at 120, 140 and 160 beats/min. In the other 10 patients similar determinations were made during sequential A-V and simultaneous ventricular and atrial (V/A) pacing, both at rates of 100 and 160 beats/min. Left ventricular ejection fraction did not change significantly with atrial pacing (from 0.65 +/- 0.02 [mean +/- standard error of the mean] at a baseline sinus rate of 91 +/- 3 beats/min to 0.62 +/- 0.03 at 160 beats/min) despite a progressive decrease in end-diastolic volume. The percent reduction in end-diastolic volume (% delta EDV) and stroke volume (+ delta SV) from the baseline values was linear and related to change in heart rate (delta HR) as % delta EDV = -0.60 delta HR + 5.19 (r = 0.71; p less than 0.01) and % delta SV = -0.62 delta HR + 5.03 (r = 0.76; p less than 0.001). Left ventricular ejection fraction with baseline sequential A-V pacing at 100 beats/min was 0.67 +/- 0.03 and not significantly altered by either sequential A-V or simultaneous V/A pacing at 160 beats/min. At 100 beats/min, loss of atrial transport with simultaneous V/A pacing resulted in a small reduction in end-diastolic volume from a baseline value of -9.0 +/- 1.9 percent (p less than 0.01) and a nonsignificant reduction in stroke volume of -3.7 +/- 1.6 percent. During simultaneous V/A pacing at 160 beats/min, the reduction in end-diastolic and stroke volumes from the baseline value was -26.6 +/- 3.8 percent and -28.8 +/- 4.3 percent, respectively (both p less than 0.01), but was significantly smaller (-16.1 +/- 3.6 percent and -19.2 +/- 4.1 percent, respectively [p less than 0.05]) when atrial transport was maintained during sequential A-V pacing at the same heart rate. During simultaneous V/A pacing at 160 beats/min, two thirds of the reduction in end-diastolic and stroke volumes from the baseline value was due to the increment in heart rate as assessed from sequential A-V pacing and the other third was due to loss of atrial transport. The data indicate that the hemodynamic consequences of supraventricular tachyarrhythmias in patients with normal ventricular function are due primarily to decreases in ventricular volume as heart rate is increased and atrial contribution is lost rather than to any changes in left ventricular ejection fraction.     

Anterolateral ST segment depression in acute inferior myocardial infarction: angiographic and clinical implications

We examined the relationship between coronary anatomy and anterolateral ST segment depression during inferior acute myocardial infarction (AMI) in 84 consecutive survivors of inferior AMI, who underwent prospective coronary angiography a median time of 2 weeks after AMI. Multivessel disease was defined as two or more significantly (greater than 70%) stenosed vessels. A QRS scoring system was used to estimate myocardial infarct size. Patients with ST depression had more multivessel disease compared to patients with no ST depression (53% vs 6%, p less than 0.01), more left anterior descending stenoses (36% vs 10% p less than 0.05), and higher QRS scores (5.8 +/- 3.2 vs 2.6 +/- 1.8, p less than 0.01) indicating larger infarcts. Patients with ST depression and one-vessel disease (47%) still had higher QRS scores compared to patients with no ST depression (4.8 +/- 2.9 vs 2.6 +/- 1.8, p less than 0.001) and had an increased prevalence of infarct-related vessels with a terminal branch supplying the left ventricular lateral wall or apex. We conclude that anterolateral ST depression during inferior AMI may indicate the presence of additionally stenosed vessels or that the infarct-related vessel has a large vascular territory. The absence of ST depression virtually precludes multivessel disease.     

Pancytopenia in an infant associated with sulfamethoxazole-trimethoprim therapy.

Pancytopenia in a seven-month-old baby is described and attributed to sulfamethoxazole-trimethoprim therapy. Plasma cells and histiocytes were prominent in the initial bone marrow examination and quite unlike the fatty hypocellular marrow usually seen in aplastic anemia.     

Carcinoid Heart Disease: Eight-Year Survival Following Tricuspid Valve Replacement and Pulmonary Valvotomy

A 34-year-old man with carcinoid heart disease underwent tricuspid valve replacement and pulmonary valvotomy with enlargement of the right ventricular outflow tract in October, 1972. He has no cardiac symptoms eight years after operation. Only four previous successful valve replacements in patients with this condition have been reported.     

The effect of fasting on liver receptors for prolactin and growth hormone

The effects of 3 day fasting on liver prolactin and growth hormone receptors have been investigated in male and female rats. Fasting caused a significant fall in serum immunoreactive insulin (67% decrease), while receptor-reactive somatomedin fell by 82% when measured in whole serum and by 72% when measured in serum fractions following gel chromatography at low pH. Tracer ovine prolactin binding to liver microsomal membranes was reduced by 55% on fasting in females, but unchanged in males. Tracer bovine growth hormone binding fell significantly in both sexes. Analysis of competitive binding curves showed the decreased binding to be due to a loss of prolactin receptors in females, and of high affinity (but not low affinity) growth hormone receptors in males and females. Significant correlations were seen between serum insulin and tracer prolactin (females) and growth hormone (males and females) binding to liver membranes. Correlations between serum insulin and liver high affinity growth hormone binding sites were particulary significant (r = 0.899 in females, r = 0.910 in males). It is proposed that the hypoinsulinemia of fasting causes a loss of high affinity growth hormone receptors in the liver, which could result in a relative hepatic resistance to growth hormone and a decreased hepatic generation of somatomedin.     

The significance of the ileocecal valve in massive resection of the gut in puppies.

Clinical observations suggest that retention of the ileocecal valve is vital for survival in neonates who undergo resection of small bowel to the extent that less than 40 cm remain. Twenty-four puppies underwent 90% resection of small bowel and 12 of these also had a destructive procedure performed on the ileocecal valve. Survival and weight patterns were used to assess results when it was found both parameters supported the clinical observations. The practical application is that all attempts should be made to retain the ileocecal valve in situations in which only short lengths of small bowel remain.