The standardization of 33P by the TDCR efficiency calculation technique.

The activity of the pure beta-emitter phosphorus-33 (33P) has been directly determined by the triple-to-double coincidence ratio (TDCR) efficiency calculation technique, thus extending the number of radionuclides that have been standardized by this simple, non-extrapolation liquid scintillation (LS) method. The major advantage of inherently accounting for chemical quenching without the need for additional external measurements is demonstrated. The 33P solution activity concentration was verified by tracing with cobalt-60, utilizing 4pi(LS)beta-gamma coincidence counting. Agreement to within 1.2% confirmed the reliability of the TDCR measurements.

Direct activity determination of 54Mn and 65Zn by a non-extrapolation liquid scintillation method.

The measurement of 54Mn and 65Zn by liquid scintillation coincidence counting results in low detection efficiencies. The activity obtained from the extrapolation of efficiency data can therefore become problematic if curvature is present. The simple decay scheme exhibited by these radionuclides, with the emission of an energetic gamma ray, allows the absolute activity to be determined from 4pie-gamma data by direct calculation without the need for efficiency extrapolation. The method, which relies on determining the probability of the gamma-ray interacting with the scintillator solution, is described and validated by measurements made on 60Co.

Preparation of solid water-equivalent radioactive standards.

The use of a superabsorbent polymer to prepare water-equivalent volume standards by solidification without the need of irradiation to effect the polymerization process, is described. Less than 40 g of the polymer is needed to solidify 1 litre of solution. Monte Carlo simulations of the gamma-ray escape probability indicate that the mixture is water-equivalent to better than 1.0%. During preparation, the solidified material can be mixed until homogeneity is achieved. Comparative measurements made before and after solidification confirmed the homogeneity and demonstrated water equivalence.

Compliant vs non-compliant balloons. A prospective randomized study.

In this prospective randomized trial we explored the possibility of different procedural outcomes with regard to compliant (polyolefin copolymer (POC)), and non-compliant (polyethylene terapthelate (PET)) balloon materials commonly used during percutaneous transluminal coronary angioplasty (PTCA). For this purpose, 51 female and 149 male (total 200) patients were randomized to 100 compliant and 100 non-compliant balloons. Only single lesions were included in the study and patients who had PTCA for more than one lesion in different segments at different sessions were each entered separately (there were actually 49 female and 143 male patients). PTCA procedures were performed in conjunction with quantitative coronary angiographic techniques and the films were reviewed by two investigators in a blinded fashion. Statistical analysis for various procedural end-points were performed by non-paired Student t test with statistical significance being p < 0.05. There were no differences in demographic and clinical characteristics between groups. Lesion characteristics of both groups were exactly matching for vessel size, balloon size, balloon vessel ratio, minimal luminal diameter and percent stenosis of the index lesion. Similarly, minimal residual diameter, percent residual stenosis, net gain, densitometric net area gain, and maximum pressure (2.2 +/- 5 mm vs 2.1 +/- 0.6 mm, 18 +/- 17% vs 23 +/- 15%, 0.8 +/- 0.5 mm vs 0.8 +/- 0.6 mm, 48 +/- 25% vs 48 +/- 26%, 7.3 +/- 2 atm. vs 6.8 +/- 3 atm., respectively) values were not statistically different between compliant and non-compliant balloon groups. Major in-hospital complications, dissections caused by the study balloon (mostly type A and B), crossover and bail-out procedures (5 vs 3, 34 vs 32, 4 vs 3, 13 vs 14, respectively) were similar for both compliant and non-compliant balloon groups. Study balloon success rate (defined as < 50% residual stenosis or > 20% net gain in the absence of major in-hospital complications, crossovers and bail-outs) and overall procedural success rate (80% vs 74%, 90% vs 85%) were not statistically different for compliant and non-compliant balloons. In conclusion, we did not observe any statistically significant difference between compliant and non-compliant balloons in terms of immediate procedural results.

Directional coronary atherectomy versus coronary angioplasty in vessels larger than 3 mm in diameter.

It has been proposed that directional coronary atherectomy (DCA) should be an intervention of choice in larger vessels as one can achieve a greater minimal luminal diameter with DCA than with percutaneous transluminal coronary angioplasty (PTCA). This in turn should translate into a higher success rate and may even reduce the restenosis rate. The aim of this study was to compare DCA versus PTCA in vessels > 3 mm in diameter. One hundred fifty consecutive patients who met the inclusion criteria and had DCA were compared to 150 similarly selected PTCA patients. PTCA patients were selected from the era immediately preceding the advent of DCA so that selections bias could be excluded. All patients with ostial lesions, restenosis, vessels < 3 mm in diameter, and vessels with more than two significant lesions were excluded. Distal segments and circumflex cases were excluded as they formed a small subsegment. Both groups were similar in terms of demographic, clinical and angiographic variables. Quantitative analysis showed that the initial net gain was significantly greater in the DCA group than in the PTCA group (2.36 +/- 0.8 mm vs. 1.78 +/- 0.7 mm; p < 0.05). Residual stenosis was 11% with DCA compared to 33% with PTCA (p < 0.05). Despite these improved anatomical results the procedural success rates were similar (91.5% vs 84%). Major in hospital complications (death, acute occlusion, MI, emergency CABG, re-do) were higher in the DCA group than in the PTCA group (12% vs 6%). Clinical follow-up on 276 patients (150 DCA vs 126 PTCA) showed a 6 month clinical restenosis rate of 18% vs 28%, respectively. The incidence of re-do in 24 hours for acute occlusion was 6% for DCA and 1% for PTCA. In large-sized vessels DCA results in a lower restenosis rate. However, despite a lower incidence of residual stenosis, the complication rate tends to be higher with DCA (p < 0.05).

Chronic orbital hematic cysts: a case for craniofacial correction.

Chronic hematic cysts are rare conditions that usually present to the ophthalmic surgeons with displacement of the globe. There is usually no, or minimal, bone involvement. Two patients with unusual presentations of chronic orbital hematic cysts are reported. These cysts resulted in significant expansion and erosion of the bony orbits. The presentation, operative findings, and reconstruction are reported and discussed.

Reconstruction of both upper and lower lips.

Major defects of both the upper and lower lips occurring in the same patient are unusual and challenging problems that could confront a plastic- or maxillofacial surgeon. We have encountered two such patients and detail their presentation, reconstructive technique used and the postoperative outcome.

Unilateral exophthalmos caused by an anterior ethmoidal meningoencephalocele.

A case of unilateral enophthalmos in a 1-year-old child is presented. This was caused by a meningoencephalocele that originated in the anterior cranial fossa and protruded into the orbit through a bony defect at the junction of the frontal and ethmoid bones at the site of the anterior ethmoid canal. This meningoencephalocele was reduced, and the dura was repaired with a temporalis fascia graft. A split calvarial bone graft was inserted into the floor of the orbit, and lateral canthal ligament elevation completed the operative correction.

A method of repairing the no. 3 facial cleft.

A method of correction of an incomplete no. 3 facial cleft in an infant is presented. It is compared with previously described repairs, and its advantages are outlined.

Spheno-maxillary meningo-encephalocele. A case report.

A patient is presented who was born with a large swelling on the left side of his face. This was removed by a paediatric surgeon at six weeks of age, and the histology was that of an encephalocele. Based on our findings at a later procedure to correct the child's facial asymmetry resulting from the congenital deformity, we concluded that this was a spheno-maxillary meningo-encephalocele. We have been able to find only one other such meningo-encephalocele reported in the literature.

Crouzon's disease. Part II. Case report--face and forehead advancement in two stages.

A child with severe Crouzon's disease had a markedly retruded forehead with exorbitism, which was treated by radical forehead advancement. At a subsequent operation, the maxillary hypoplasia was corrected by a Le Fort III osteotomy and face advancement.

Crouzon's disease. Part I. One-stage correction by combined face and forehead advancement.

Crouzon's disease results in maxillary hypoplasia and a receding forehead, which produce characteristic exorbitism. Total correction of the deformity by Le Fort III osteotomy and face advancement with a simultaneous forehead advancement corrects all the deformities. The advantages and disadvantages of this major craniofacial procedure are discussed after 2 case descriptions.

The treatment of late post-traumatic orbital deformities.

Trauma to the orbital region may result in fractures of the bony orbit, displacement of which gives rise to malposition of the eye and diplopia. If initial treatment is not feasible or is unsuccessful, later correction may be achieved by osteotomy or reduction and stabilisation of the bony fragments, often with bone grafts. Displaced medial or lateral canthi may need to be repositioned, where feasible in an overcorrected position. Where bone grafts are necessary, the skull is now favoured as the best donor site.

Acute hemodynamic and neurohumoral effects of pindolol: a beta-adrenoceptor antagonist with high intrinsic sympathomimetic activity in patients with dilated cardiomyopathy.

It has been claimed that beta-adrenoceptor antagonists produce clinical improvement and increase longevity in patients with idiopathic dilated cardiomyopathy. Dilated heart is critically dependent upon adrenergic support to maintain forward output. Acute withdrawal of such support, even with small doses of beta-blockers, may worsen myocardial function sufficiently to limit their widespread use. Pindolol (P), a potent beta-adrenoceptor antagonist, possesses high intrinsic sympathomimetic activity. Administration of P to patients with dilated cardiomyopathy may protect against the effects of high circulating catecholamines and at the same time partially maintain intrinsic left ventricular function. We examined the acute hemodynamic effects of P (2.5 mg orally) in seven patients with dilated cardiomyopathy (average ejection fraction, 23%) and resting tachycardia (average, 111 beats/min). As compared to baseline values, P produced a highly significant fall in heart rate (rest, 19%, p less than 0.001; exercise, 24%, p less than 0.01), cardiac output (rest, 20%, p less than 0.01; exercise, 25%, p less than 0.001), and systemic arterial pressure (exercise only, 13%, p less than 0.05). Calculated systemic vascular resistance increased significantly at rest (17%, p less than 0.05). Pulmonary artery pressures did not change. Compared to normal subjects, baseline norepinephrine levels were markedly elevated in patients with dilated cardiomyopathy at rest and during exercise. Pindolol produced a further significant increase in norepinephrine levels. Two of seven patients became appreciably short of breath after P. Despite its substantial intrinsic sympathomimetic activity, pindolol, like other beta-adrenoreceptor antagonists, produces significant hemodynamic impairment in patients with congestive cardiomyopathy. An exaggerated norepinephrine response after the drug may, by increasing peripheral vascular resistance, lead to further deterioration in left ventricular performance.

Hemodynamic and neurohumoral effects of ketanserin, a 5-HT2 receptor antagonist in patients with congestive heart failure.

Ketanserin, a recently developed 5-HT2 receptor antagonist, competitively and selectively blocks the vasoconstrictor activity of 5-hydroxytryptamine (serotonin). We explored a possible contribution of serotonin to augmented vascular tone in patients with severe heart failure, using intravenous and oral formulations of ketanserin. When administered intravenously (10 mg bolus, 4 mg/hr infusion for +/- 40 min) to 10 patients with congestive heart failure (NYHA III or IV) secondary to congestive cardiomyopathy (n = 8) or ischemic heart disease (n = 2), the drug produced a significant increase in cardiac output (rest 24%, p less than 0.001; exercise 19%, p less than 0.01) which was accompanied by a fall in systemic arterial pressure (rest 7%, p less than 0.001; exercise 10%, p less than 0.05) and pulmonary wedge (rest 17%, p less than 0.05; exercise 23%, p less than 0.001) pressure. Calculated systemic vascular resistance (SVR, rest 27%, p less than 0.001; exercise 23%, p less than 0.05) decreased significantly. No significant hemodynamic changes were observed when 40 mg of ketanserin was administered orally to the same group of patients. Plasma catecholamines (norepinephrine, NEP:epinephrine, EP:dopamine) were measured before and after ketanserin at rest and during exercise. Baseline NEP levels were markedly elevated at rest and during exercise in all patients (rest: 878 +/- 381 ng/mL, exercise: 1453 +/- 697 ng/mL). Baseline EP levels were within normal limits. Ketanserin did not produce any change in catecholamine concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Favorable effects of pindolol in dilated cardiomyopathy.

We describe the clinical course of a patient with tachycardia at rest, biopsy proven dilated cardiomyopathy, and moderately severe left ventricular systolic dysfunction. Short-term use of pindolol produced a significant fall in heart rate and cardiac output at rest and during exercise. However, after addition of pindolol to the patient's previous regimen of digoxin and furosemide, he made a rapid clinical recovery and has maintained clinical improvement during the last four years of follow-up. The pattern of clinical response suggests that pindolol may have contributed substantially to this patient's recovery.

The Pietermaritzburg craniofacial unit.

The Pietermaritzburg Craniofacial Unit was established in 1976, and since its inception 150 patients with major skull and facial deformities have been referred there from centres throughout South Africa. Fifty craniofacial operations have been performed by the surgeons of the Unit, who form only a part of a team of 16 members from many branches of the medical, dental and allied professions. Craniofacial surgery is defined and reasons are presented for limiting the number of such highly specialized units.