The effects of prostaglandins E1, E2, F1α and F2α on guinea-pig ileal and colonic peristalsis

Prostaglandins (PGE₁, E₂, F_1α and F_2α) have been tested on the peristaltic reflex in isolated segments of guinea-pig ileum and colon using simultaneous recordings of fluid propulsion and longitudinal and circular muscle activity. Propulsion and circular muscle peristaltic activity were increased by serosally applied PGF compounds in the ileum and PGE or PGF compounds in the colon following initial contraction of the longitudinal muscle. This is consistent with a role for prostaglandins in peristalsis. Mucosally applied PGF compounds had no significant effect.     

LIPODYSTROPHY WITH HYPERLIPIDAEMIA: THE ROLE OF INSULIN IN VERY LOW DENSITY LIPOPROTEIN OVER-SYNTHESIS

A patient with partial lipodystrophy is described in whom hypertriglyceridaemia was accompanied by marked hyperinsulinaemia. The hyperlipidaemia was due to increased plasma levels of very low density lipoprotein (VLDL). Kinetic studies, performed after injection of autologous radioiodinated VLDL, indicated that the raised VLDL levels were associated with over-production of this lipoprotein. Administration of diazoxide led to a substantial fall in serum insulin levels, accompanied by reduction in VLDL production and in serum triglyceride concentration. The possible role of insulin in inducing hyperlipidaemia by causing over-production of VLDL is discussed.     

The effect of social selection on the population dynamics of Huntington''s disease

Wallace (1976) postulated the importance of social selection on the frequency of Huntington's disease. This effect of social selection was studied with respect to the population dynamics of Huntington's disease genes. It is shown that social selection operates mainly through heterozygotes. Existing data indicate that the frequency of Huntington's disease in the population is determined by its social effects.     

Arteriovenous Fistula: A Complication of Cardiac Pacemaker Lead Placement and Its Management with Percutaneous Embolization

A right infernal mammary artery to right brachiocephalic vein fistula was discovered following implantation of a permanent cardiac pacemaker. The fistula was closed via percutaneous embolization.     

Patient Characteristics Associated with Retention in a Methadone Maintenance Program

The purpose of this study was to determine if it is possible to differentiate between types of patients as to their ability to stay in a methadone maintenance program. Since medical and counseling staff cannot work with ail patients simultaneously, such information would be helpful in identifying who needs the most help. This study is based on most admissions (679 cases) to the Dole-Nyswander methadone maintenance program from its initiation in 1964 to 15 March 1968. Each patient was followed-up to determine whether they were still in the program 2 years later. This meant the last admissions were followed to 15 March 1970. Eighty percent of both males and females were continuously in the program for 2 years or longer. (1) As expected, those patients who did poorer were those who, had longer conviction records, were multiple drug users, abused alcohol, were not employed at admission, were older and were not married. (2)Other factors that were expected to be related to program stay, but proved to have little or no relationship were; age when started using heroin, number previous hospitalization, length of education and longest job held. (3)Patients with relatively short usage or very long usage did better than those in the middle range (8 to 19 years of use). (4)When clinical experience was used as a guide for combining single factors some interesting classifications of patients emerged. For example, the best group were those who were abusers for 5 years or less and had no multiple drug or alcohol abuse. This group had a 96 percent outcome rate. The poorest group were those who had 12 to 15 years of abuse and 7 or more convictions. This latter group had 58 percent in program 2 years after admission. (5)When the single factors were combined by using configural analysis, a somewhat different patient classification was developed. The patient types had outcome rates which ranged from 56 to 94 percent.     

Serial Lead Impedance Measurements Confirm Fixation of Helical Screw Electrodes During Pacemaker Implantation

The purpose of this study was to determine whether serial measurements of helical screw pacemaker lead impedance could reliably confirm electrode fixation in the right atrium and right ventricle. Fixation is generally assessed fluoroscopically, which can be misleading because the myocardium is radio lucent. Alternatively, because the electrical conductivity of blood is greater than that of myocardium, serial measurements of the lead impedance might be expected to show an impedance increase with appropriate fixation of the pacemaker electrode when the electrode becomes embedded in myocardial tissue. Impedance measurements were made during the placement of 23 atrial and 28 ventricular active fixation electrodes in 31 consecutive patients. Impedance measurements were recorded in unipolar and bipolar electrode configurations with the electrode free floating in the chamber, unfixed (with exposed screws) but touching the endocardial surface, and after fixation. No significant impedance differences were found between free-floating and unfixed electrode positions. With fixation, the lead impedance increased significantly in the ventricle (P = 0.0001, unipolar and bipolar) and the atrium (P = 0.0069 unipolar and 0.0052 bipolar). Typical increases, reflected by median values, were 197 ohms unipolar and 203 ohms bipolar in the ventricle and 47 ohms unipolar and 53 ohms bipolar in the atrium for electrodes with permanently exposed or retractable screw designs. Comparing serial measurements of lead impedance before and after electrode fixation is a valid electrical method of confirming appropriate fixation of helical screw electrodes.