The smooth muscle from the human internal anal sphincter has been investigated pharmacologically in vitro. The upper and lower parts of the sphincter responded to catecholamines in a similar manner. Noradrenaline caused contraction which could be antagonized by phenoxybenzamine. After phenoxybenzamine, noradrenaline caused relaxation which could be blocked by pronethalol. Isoprenaline caused relaxation which could be specifically prevented by pronethalol. Adrenaline was variable in its effect: low concentrations caused relaxation and high concentrations caused contraction. It is suggested that the anal smooth muscle contains alpha-adrenergic receptors subserving contraction and beta-receptors subserving relaxation. The lower part of the sphincter was generally insensitive to acetylcholine and nicotine whereas the upper part of the sphincter contracted with acetylcholine and regularly relaxed with nicotine. The nicotine response was antagonized by hexamethonium, procaine, and pronethalol. It is suggested that nicotine stimulated some part of the nervous mechanism in the upper part of the sphincter and that a catecholamine was the mediator of the inhibitory response.

Acetylcholine↗

PubMedDate not supplied

Phase contrast microscopy. Diagnosis of ghost cell glaucoma following cataract extraction.

Ghost cell glaucoma may be suspected when intraocular pressure remains elevated following vitreous hemorrhage. Vitrectomy provides relief of the glaucoma and an improvement in vision. The vitrectomy specimen offers confirmation of the clinical diagnosis when examined by phase contrast microscopy.

Aged↗

PubMedDate not supplied

Unsuspected infectious keratitis in host corneal buttons.

Infectious keratitis may be unsuspected preoperatively in patients undergoing penetrating keratoplasty. We have diagnosed five cases of previously unknown corneal infection discovered only after post-keratoplasty histopathologic examination using specific stains. These cases of preoperatively unsuspected infectious keratitis illustrate examples where histopathologic examination using specialized stains may alert the physician to the need for appropriate postoperative antimicrobial therapy. Furthermore, these cases illustrate the ability of soft contact lenses to mask symptoms of infectious keratitis. Additionally, the clinical appearance of advanced bullous keratopathy may mask signs of infectious keratitis.

Acanthamoeba↗

PubMedDate not supplied

Reproducibility of arterial compliance and carotid wall thickness measurements in normal subjects.

1. Non-invasive techniques to measure indices of arterial function and wall thickness are frequently used as surrogate markers of cardiovascular disease. Reproducibility of measurements of arterial compliance has been infrequently reported and little is known about the interrelationships of the various indices in vivo. 2. The present study was designed to assess reproducibility and interrelationships of indices of systemic arterial compliance, pulse wave velocity, carotid compliance and intima-media thickness (IMT). 3. Fifty healthy volunteers (20 male and 30 female: aged 20-70 years, mean 46.5 years), participated in the present study. Each subject was studied on two occasions by the same investigators, using an identical protocol at an interval of 1-5 weeks (mean 2.5 weeks) without lifestyle change. 4. There were no significant differences between visits for any recorded general data, except resting blood pressure, which was lower on the second occasion. There were no systematic differences within each pair over the range of measurements for any of the variables. Bland-Altman plots of repeatability of changes in indices showed that the mean values between visits were not significantly different. All indices of central arterial compliance were significantly related to age and IMT. 5. Thus, under controlled experimental conditions, there was satisfactory repeatability of measurements of indices of both intrinsic and functional arterial mechanical properties (central and carotid arterial compliance and IMT). This type of information will permit the construction of sample size tables for clinical trials using these indices. 6. Central arterial compliance may be an important determinant of IMT.

Adult↗

PubMedDate not supplied

Circadian rhythms of heart rate and blood pressure after heart transplantation.

Blood pressure and heart rate were recorded over 24-hour periods on 39 occasions in 20 subjects 5 to 72 weeks after heart transplantation. All patients were receiving cyclosporine, azathioprine, and prednisolone. In 38 of the 39 records the mean nighttime heart rate was lower than the mean daytime rate, with a peak difference of 20.1 +/- 1.8 beats/min. Blood pressure responses were, however, of two patterns. In 15 of the 39 recordings (approximately 50% of patients) the mean nighttime systolic pressure was higher than the mean daytime systolic pressure; in the remainder the converse was observed. The pattern was generally consistent on repeated recordings from the same patient and was not related to time since transplantation, renal function, or other therapy. Echocardiographic/Doppler studies were available at the time of 31 of these recordings. No differences in left ventricular diameters, systolic function, or transmitral filling patterns were present between patients whose blood pressure was higher or lower at night. Left ventricular posterior wall thickness and the ratio between wall thickness and ventricular diameter at end diastole were greater in the group showing nighttime pressure falls. Blood pressure responses after heart transplantation show the presence of nighttime "dippers" and "nondippers." At least early after transplantation, however, nondipper status is not preferentially associated with the development of left ventricular hypertrophy. The mechanisms accounting for the different circadian blood pressure responses in heart transplant recipients are not known.

Blood Pressure↗

PubMedDate not supplied

Silver modification of polyethylene terephthalate textiles for antimicrobial protection.

The safety and in vitro effectiveness of applying silver to polyethylene terephthalate fabric mechanical heart valve (MHV) sewing cuffs for the prevention of prosthetic valve endocarditis (PVE) were evaluated. PVE is an infrequent but grave complication of cardiac surgery associated with mortality rates potentially exceeding 50%. A poor response to antibiotic therapy is partly responsible for the high mortality rates. Silver is a well known antimicrobial agent with broad effectiveness. Preliminary in vitro microbial challenge studies of the coated fabric using the New York State 63 bacteriostatic test and Dow Corning Shake Flask test showed a > or = 97% reduction for most organisms tested. Sheep mitral valve replacement studies suggest comparable tissue ingrowth of uncoated and coated fabric with a more organized, thinner pannus formed on silver coated fabric. Low levels of silver were present in the serum at all time periods. These results indicate MHVs with silver coated cuffs may provide additional protection against PVE.

Animals↗