Two different mechanisms are involved for the bleomycin-induced DNA repair synthesis in permeabilized HeLa cells

Bleomycin-induced DNA repair synthesis in the permeabilized HeLa cells was sensitive to aphidicolin, an inhibitor of DNA polymerase alpha and delta, and to dideoxythymidine triphosphate (ddTTP), a specific inhibitor of DNA polymerase beta. Upon combined treatment with these inhibitors, the DNA repair synthesis was inhibited to an even higher degree. This indicated that the aphidicolin- and ddTTP-sensitive DNA repair syntheses may occur by independent mechanisms. The structure of incomplete repair patches being accumulated in the presence of these inhibitors was investigated by digestion of DNA with exonuclease III after incubation with Klenow fragment and T4 DNA ligase. The results have suggested that the patch accumulating in the presence of aphidicolin is a single-stranded gap made by excision enzyme(s), whereas that accumulating in the presence of ddTTP may be generated by strand displacement.

Percutaneous fine needle aspiration biopsy of pancreatic cancer guided by ultrasonography

Fine needle aspiration biopsy guided by ultrasonography was performed in 39 patients with pancreatic cancer to evaluate the value of the technique for establishing a proved histologic diagnosis. Aspirated material suitable for cytologic evaluation of smear preparation was obtained from 33 patients (84.6%). Among the 33 patients, cytologic diagnosis of pancreatic cancer was possible in 28 patients (84.9%). There was mild abdominal pain only in one patient (2.6%). In conclusion, percutaneous fine needle aspiration biopsy guided by ultrasonography proved to be a safe and useful method for histologic diagnosis of pancreatic cancer.

Fibrinolytic response to standardized venous occlusion in different age groups

The purpose of this study was to find out the range and distribution of fibrinolytic response to standardized venous occlusion in healthy volunteers and to determine whether there were any differences according to age and sex. In 118 healthy volunteers (55 males, 63 females) of various age groups, the total fibrinolytic activity in euglobulin fractions was measured by a well controlled fibrin plate method before and after venous occlusion of 5 minutes at 100 mmHg. The difference between our method and previous methods is that we occluded for a relatively shorter duration than that of previous studies (15-20 minutes) at constant pressure (100 mmHg), instead of midway between systolic and diastolic pressure. This method was reliable and reproducible as a tool to qualify and assess the fibrinolytic activity capacity of individuals. The results showed that there was no difference in basal fibrinolytic activity and the response to stimuli in various age groups (p greater than 0.25) and in male and female groups (0.1 less than p less than 0.375).

Germanium:gallium photoconductors for far infrared heterodyne detection

Highly compensated Ge:Ga photoconductors have been fabricated and evaluated for high bandwidth heterodyne detection. Bandwidths up to 60 MHz have been obtained with corresponding current responsivity of 0.01 A/W.

Pentoxifylline therapy: a new adjunct in the treatment of pulmonary hypertension?

Patients with markedly elevated pulmonary vascular resistance, whether caused by primary pulmonary hypertension or by congenital heart disease, have a grave prognosis, regardless of the type of therapy they undergo. This brief report presents our experience in treating 6 patients (4 women and 2 men) having pulmonary vascular obstructive disease, by administrating pentoxifylline (Trental), a drug that has been used in patients with chronic occlusive systemic arterial disease. Our patients underwent treadmill testing before the study and again 1 to 3 months after initiation of the study. Duration of exercise was short in all patients; however, it increased significantly while patients were taking pentoxifylline. These preliminary results are encouraging; however, we were unable to confirm other physiologic improvement with noninvasive study, and placebo effect was not ruled out. Therefore, we believe that use of pentoxifylline in patients with pulmonary vascular obstructive disease warrants further investigation by means of detailed direct hemodynamic measurement.

Severe diffuse obstructive coronary artery disease in an infant

Severe diffuse obstruction of the coronary arteries was diagnosed in an 18-month-old girl who presented with signs and symptoms of severe congestive cardiomyopathy. Most reported cases of myocardial infarction in neonates or infants have been secondary to obstruction of a single major coronary artery owing to thrombosis or embolism; diffuse multiple obstruction involving the entire coronary artery system, as in our case, has not previously been described. Although the exact cause of the obstruction remained unknown, the most likely mechanism was in situ thrombosis.

Total correction of tetralogy of fallot in adults: surgical results and long-term follow-up

From 1962 to 1983, 117 patients between the ages of 16 and 72 years (mean, 25 years) underwent total correction of tetralogy of Fallot. All patients were operated on because of recent deterioration. Eighty (68%) had had previous surgical palliation. Complications occurred in 38 cases (32%) before total correction and were more frequent in older patients. The hospital mortality was 7.8% and was highest in older patients and those with a previous Potts shunt. Fifty-nine patients were followed up for as long as 23 years (mean, 9.2 years) after total correction. The probability of survival at 5, 10, and 15 years after total correction was 96%, 96%, and 84%, respectively. The actuarial freedom from any significant cardiovascular event at 5, 10, and 15 years was 84%, 73%, and 50%, respectively. Reoperation was required in ten cases (17%), in which there was one operative death. Late death occurred in four cases (6.8%). Left ventricular dysfunction was documented in ten patients (17%), three of whom had mural thrombi and two of whom had cerebrovascular accidents. A significant rhythm disorder was present in 13 patients. Fifty-four of the 55 surviving patients were in New York Heart Association (NYHA) functional class I or II at last follow-up. We conclude that 1) total correction of tetralogy of Fallot in adults is associated with a low operative mortality, similar to that in children, and offers symptomatic relief in most cases; 2) the long-term survival is excellent, but late sequelae become more frequent at late follow-up; 3) "corrective" reoperation can be done with a low risk; and 4) most of the survivors are in NYHA functional class I or II and lead normal, productive lives.

Analysis of cases of nonvisualized gallbladder by ultrasonography

To define the significance of nonvisualization of the gallbladder by ultrasonography, we studied follow-up data on 31 cases in which the gallbladder could not be identified despite adequate fasting. Thirty one cases of gallbladder disease included 15 cases of chronic cholecystitis due to cholelithiasis (13 cases) and choledocholithiasis (2 cases), 4 cases of cholelithiasis which were not surgerized, and 3 cases of cancer. There were 4 cases of diagnostic error in which gallbladder nonvisualization occurred despite a demonstrable lumen. The etiology of disease was not determined in the 5 remaining cases. Therefore 22 of 26 cases were found to have diseased gallbladders. The resasons for nonvisualization of the gallbladder by ultrasonography in the 19 cases which underwent surgicl exploration were: 17 cases due to chronic cholecystitis with cholelithiasis (13 cases), choledocholithiasis (2 cases) and cancer (2 cases), obliteration of the lumen due to cancer of the gallbladder in one cases, and technical error due to an unusual location of the gallbladder in one case. The mechanisms of diagnostic error in 4 cases seemed technical error due to an unusual location of the gallbladder in 3 cases and the obscured gallbladder by intestinal gas in one case. In conclusion, we feel that careful examination should be done to detect a gallbladder located unusually or obscured by intestinal gas in order to decrease the rate of diagnostic error when the gallbladder is not visualized by ultrasonography. Also, we recommend an oral cholecystography or ERCP for ultrasonic nonvisualized gallbladder.

A study of 122 cases of pancreatic cancer diagnosed by endoscopic retrograde cholangiopancreatography (ERCP)

ERCP is a highly accurate and specific method for evaluating patients with suspected pancreatic disease. Its diagnostic significance of specific pancreatographic signs is of even greater importance. We reviewed 122 cases of pancreatic cancer who were done ERCP, at the Department of Internal Medicine, Yonsei University, College of Medicine between June 1973 and August 1983. The results were as follows: 1. The ages of 122 patients ranged from 27 to 76 with the majority in the 6th and the 7th decades. The male to female ratio was 2.49:1. 2. The success rate of cannulation into the orifice of the duodenal papilla in 122 cases was 97.5% (119/122), and the pancreatic duct was visualized in 91.0% (111/122). 3. Diagnostic accuracy of ERCP in pancreatic cancer was 96.4% (107/111) among cases in whom the pancreatic duct was visualized. 4. By ERCP the most common site of the lesion was head of pancreas (51.4%). 5. According to Fukumoto’s classification, the most common type was obstructive type (65.4%), followed by the stenosing type (29.0%), abnormal branching type (3.7%), and narrowing type (1.9%). 6. According to Takaki’s classification, Type I (obstruction or stenosis of the main pancreatic duct) was most common (85.6%), followed by Type III (pancreatic dilatation) (9.0%), Type IV (normal pancreatic duct) (3.6%), and Type II (obstruction of Wirsung’s duct or Santorini’s duct) (1.9%). 7. Of the 122 cases of pancreatic cancer, the bile duct was visualized in 55 and abnormalities, such as indentation (32.1%), stenosis (42.9%), and obstruction (25.0%) were found in 28. The locations of abnormal findings in the bile duct were distal (50.0%), middle (46.4%), and proximal (3.6%).

Developmental changes in response of dog isolated ventricular myocardium to norepinephrine

There are maturational changes of myocardial function and response to inotropic agents. Because of incomplete myocardial sympathetic innervation, neonatal myocardium may be more sensitive to norepinephrine than is adult myocardium. We tested this hypothesis by using isolated trabecular muscle from two groups of puppies and from adult dogs. The muscles were exposed to norepinephrine at concentrations of 1 x 10(-10) to 1 x 10(-4) M, and indices of isometric and isotonic contraction were measured. Active tension and maximum rate of contraction increased in all age groups with norepinephrine. Adult dogs were more sensitive than puppies to the arrhythmogenic effect of norepinephrine. Although there was no strictly significant difference statistically, there appeared to be an age-related increase in the dose at which 50% of the maximum effect of the drug was achieved (ED50). Total contraction time, time to peak tension, and relaxation time decreased with increasing concentrations of norepinephrine in older puppies and in adults but not in newborn puppies. Thus, there are significant age-related differences in response to norepinephrine.

Comparative response of the developing canine myocardium to inotropic agents

Developmental changes in cardiac muscle function were assessed in isolated dog ventricular muscle strips obtained from dogs of three age groups: 2 day, 4 wk, and adult. Active tension (AT) and maximum rate of contraction and relaxation (+dT/dt, -dT/dt) increased significantly with age. Total contraction time increased with age. Time to peak tension increased between 4 wk and adulthood, and relaxation time increased between 2 day and 4 wk (P less than 0.05). The degree of post-"extra stimulus" potentiation in response to a single premature extra stimulus (SPES) or to sustained paired stimulation (SPS) was similar in all age groups. However, a longer period of SPS was necessary to reach peak AT in young animals than in adults. AT, +dT/dt, -dT/dt, and (-dT/dt)/T increased significantly in all age groups in response to increasing concentrations of isoproterenol. However, while (+dT/dt)/T increased significantly in the 4-wk and adult groups, it remained unchanged from control in the 2-day group with increasing concentration of isoproterenol. The ED50 of isoproterenol was significantly greater in the 2-day and 4-wk groups than in the adult group. AT increased significantly in young muscles but not in adult muscles when additional calcium was added to the bath containing the highest concentration of isoproterenol. In adult muscles SPS produced the greatest AT but not in the 2-day group, which required increased calcium concentration as well as isoproterenol. Maturation of several membrane systems is implicated.