Calbindin-D28k-containing neurons in the human hypothalamus: relationship to dopaminergic neurons.

Calbindin-D28k is a calcium-binding protein that protects nerve cells from degeneration. It is located in the midbrain dopaminergic neurons that are relatively invulnerable to degeneration in Parkinson's disease. Because the hypothalamic dopaminergic neurons do not degenerate in Parkinson's disease, the present study sought to determine whether these neurons also contain calbindin-D28k. Using immunocytochemical staining with antibodies against calbindin-D28k and tyrosine hydroxylase, and computer imaging techniques, the distributions of calbindin-D28k and tyrosine hydroxylase-containing neurons were mapped. Both neuronal populations were present throughout the rostral-caudal extent of the hypothalamus. However, only in the periventricular region, at the preoptic and anterior hypothalamic levels, was there an overlap in the two cellular distributions. Using the presence of neuromelanin pigment as a marker for dopaminergic neurons, approximately 30% of the dopaminergic neurons contain calbindin-D28k in the periventricular region. These data indicate that a sub-population of hypothalamic dopaminergic neurons contain calbindin-D28k. This finding is discussed in terms of why hypothalamic dopaminergic neurons are resistant to degeneration in Parkinson's disease.

Postmortem diagnosis of acute anaphylaxis by serum tryptase analysis. A case report.

Systemic anaphylaxis is an acute allergic emergency resulting from generalized mast cell degranulation. In the United States, it is estimated that anaphylaxis accounts for about 500 deaths each year. Hymenoptera-sting hypersensitivity is one of the most common causes of systemic anaphylaxis. The authors report a case of a healthy 26-year-old man who developed acute anaphylaxis after a bee sting, could not be resuscitated, and died within 1 hour. At autopsy, performed 14 hours after the event, the only pathologic findings were laryngeal edema and congestion of lung. Postmortem tryptase levels in the blood were obtained and were instrumental in confirming a diagnosis of acute anaphylaxis. This case is reported to discuss the difficulties associated with using traditional histamine levels in making a diagnosis of anaphylaxis and to validate the value of using tryptase levels to document acute anaphylaxis as a cause of death, even when serum is not obtained until many hours after death.

Four-year patency of PTFE grafts after replacement of the superior vena cava and the innominate veins.

We describe a simpler alternative to treating vena cava syndrome with composite spiral vein grafts. Instead, we used 2 polytetrafluoroethylene (PTFE) grafts to replace the resected superior vena cava and innominate veins of a man with a malignant thymoma. Both grafts have remained patent more than 4 years after surgery, and the patient has continued asymptomatic and free of malignancy. Therefore, we recommend using PTFE grafts to replace the great veins of the thorax.

Cardiac surgery in patients with end-stage renal disease.

In a retrospective study we analyzed the clinical features of 85 patients with end-stage renal disease who underwent cardiac operation. Seventy-eight patients were from reports in the literature, and 7 were from our experience. The cardiac procedures were primarily valve replacements and aortocoronary bypass (ACB) operations. The indication for valve replacement was most commonly infective endocarditis (73%), affecting most frequently the aortic valve (68%). The most common organism was Staphylococcus aureus, and there was a recent episode of angioaccess site infection in at least 17.5% of patients with documented endocarditis. The 30-day mortality was 57% for patients undergoing emergency valve replacement and only 3% for similar elective operations. Cumulative survival at 48 months was equal to that of the overall hemodialysis population not having cardiac operations. The mean age (50 years), male to female ratio (9:1), number of vessels bypassed per patient (2.4), and operative mortality for ACB were equal to those reported in comparable series of patients with normal renal function. Cumulative survival at 48 months for ACB patients was similar (60% versus 56%) to that of the overall hemodialysis population. Cardiac operations can be performed safely in patients with end-stage renal disease; the morbidity and mortality are similar to those encountered in patients with normal renal function. The long-term survival after cardiac procedures in patients with end-stage renal disease is similar to that reported for the overall hemodialysis population not having cardiac operations.

Seeding of arteriovenous prostheses with homologous endothelium. A preliminary report.

Endothelial cell seeding of expanded polytetrafluoroethylene (e-PTFE) arteriovenous prostheses was performed to compare seeding with homologous vs. autologous cells and to study the effect of homologous seeding with a larger vs. a smaller number of cells. Sixteen dogs were randomly assigned to four equal groups: I, control; II, light homologous seeded; III, heavy homologous seeded; and IV, autologous seeded. Bilateral femoral arteriovenous loop grafts were inserted in all. Efficiency of seeding was assessed by cell counts of instilled vs. retained cells. All grafts remained patent and were harvested approximately 8 weeks after implantation. Samples were evaluated grossly by scanning electron microscopy and light microscopy. There was a direct correlation between number of cells instilled and number retained for each graft; group III received and retained the largest number (p less than 0.001 and p less than 0.05, respectively). The amount of thrombus deposition on the lumen of all grafts was grossly the same. Endothelium was demonstrated in samples obtained from the midgraft of groups III and IV; in contrast no endothelium was seen in groups I and II. The percentage of endothelialized surface was not determined. No immunologic cellular reaction was detected in any of the samples. We conclude that in the animal laboratory it is possible to seed e-PTFE arteriovenous prostheses successfully with homologous cells and to improve the efficiency of seeding by implanting a larger number of cells obtained from an endothelial cell bank. The potential applications of this technique to the clinical field are discussed herein.

Chemical and microbiologic characteristics and toxicity of povidone-iodine solutions.

The chemical, microbiologic, and toxic characteristics of povidone-iodine solution, a commonly used antiseptic agent, are addressed in a collective review of relevant works published from 1956 to the present. Interactions of this agent with the thyroid gland and the kidneys and its toxicity at the cellular and systemic level are discussed.

Rest and exercise hemodynamics following aortic valve replacement. A comparison between 19 and 21 mm Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves.

When aortic valve replacement is performed in a patient with a small anulus, significant obstruction of the left ventricular outflow tract may remain. Most prostheses are obstructive in the smaller sizes, and enlargement of the aortic anulus may be required to allow placement of a larger valve. To evaluate the hemodynamic performance of two commonly used tissue prostheses, the Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves, 22 patients with either the 19 or 21 mm size were electively studied at rest and after exercise at a mean of 15 months after operation. The resting mean transvalvular gradient for 19 mm Ionescu-Shiley pericardial valves (n = 7), 10.6 +/- 9.2 mm Hg, was significantly lower than that for 19 mm Carpentier-Edwards valves (n = 3), 33.3 +/- 2.1 mm Hg, p less than 0.01. Following exercise, the mean gradient for 19 mm Ionescu-Shiley pericardial valves rose only to 13.8 +/- 8.5 mm Hg. No exercise data were available for the 19 mm Carpentier-Edwards valve. Among patients with 21 mm Ionescu-Shiley pericardial valves (n = 7), the mean transvalvular gradient at rest was 5.6 +/- 9.5 mm Hg, not significantly different from that of patients with 21 mm Carpentier-Edwards valves (n = 5), 9.8 +/- 18.3 mm Hg. After exercise, the gradients rose to 16.0 +/- 10.0 mm Hg and 25.5 +/- 23.8 mm Hg for the Ionescu-Shiley pericardial and Carpentier-Edwards valves, respectively (no statistical significance). Cardiac index was not different between groups. Gradients were not significantly higher in patients with body surface areas greater than 1.5 m2. It is concluded that the 19 and 21 mm Ionescu-Shiley pericardial valves possess excellent hemodynamics, even after exercise. This valve appears hemodynamically superior to the Carpentier-Edwards valve, particularly in the 19 mm size. Procedures to enlarge the aortic anulus are usually unnecessary when small Ionescu-Shiley pericardial valves are used, even in patients who have large body surface areas.

Inhibition of povidone-iodine's bactericidal activity by common organic substances: an experimental study.

An in vitro study demonstrated that some organic substances commonly present in the surgical field inhibit the bactericidal activity of dilute povidone-iodine solutions. The degree of inhibition was inversely proportional to the concentration of the povidone-iodine solutions and it was greatest by blood, followed by pus, fat, and glove powder. The pattern of bacterial kill was virtually identical for all the strains tested. The most likely explanation for this phenomenon is that iodine is bound by the organic substances, decreasing the iodine available for bacterial kill. To obtain an optimal benefit, we suggest eliminating these substances from the operative site or wound when possible before the use of povidone-iodine solution.

Hemodynamic and morphologic features of arteriovenous angioaccess loop grafts.

Bilateral femoral A-VLG (5 acute, 5 chronic) were implanted in 10 dogs (e-PTFE, 6 mm ID, 25 cm length). Acute studies included measurements of cardiac output (CO) and systemic vascular resistance (SVR). Blood pressure and pressure waveforms in the graft were obtained by retrograde catheterization and pull-back readings. Chronic dogs were sacrificed 8 wks postimplant; samples were obtained following a standardized protocol and studied by light microscopy (LM) and scanning electron microscopy (SEM). Hemodynamic data show a rise in CO, a decline in SVR and a high flow through each graft. Pull-back readings show a gradual drop in pressure and loss of pulsatility from the arterial to the venous side of the graft. LM studies show IH primarily in the proximal vein. SEM showed limited pannus ingrowth endothelium close to the anastomoses and otherwise a thrombus layer throughout the lumen. A-VLG are associated with high flow, pressure drop and loss of pulsatility. Proximal vein IH is a reproducible lesion. We conclude there is severe hemodynamic stress from disturbed flow and high flow velocity and it plays a critical role in the development of venous intimal hyperplasia in AV loop grafts.

Hemodialysis-associated carpal tunnel syndrome. A clinical review.

The clinical features of 88 patients who developed carpal tunnel syndrome (CTS) in association with end stage renal failure and chronic hemodialysis were studied (11 original cases and 77 collected from the literature). Hemodialysis-associated CTS was found to have a 2 to 1 male predominance, to occur more often in angioaccess-bearing (86%) than in unoperated arms (48%) (p = 0.005), and to require surgical release of the median nerve in most of the cases (86%). The analysis of 48 of these patients revealed two patterns of presentation. Patients with the 'early pattern' (41.6%) developed CTS within 1 year of commencing hemodialysis; diabetes mellitus and/or severe polyneuropathy were present in at least 40%. In contrast, patients with the 'late pattern' (58.4%) developed symptoms after at least 1 year on hemodialysis; diabetes mellitus and/or polyneuropathy were present in less than 10%. CTS should be considered in any hemodialysis patient with upper extremity neurological symptoms; early diagnosis and treatment will prevent loss of hand function.

Popliteal vein pseudoaneurysm: a case report.

This is a case report of an athletic, middle-aged man with a remote history of penetrating right leg trauma who developed a pulmonary embolism, thrombosis of the popliteal vein, a mass in the popliteal fossa, and acute ischemia of the right lower leg. At operation a thrombosed pseudoaneurysm was found arising from a defect in the popliteal vein with extrinsic compression of the popliteal artery. The defect was patched with autogenous vein and the long-term result was excellent. Pseudoaneurysm of the popliteal vein is a previously unreported entity. Popliteal venous aneurysms usually begin with phlebitic or pulmonary thromboembolic manifestations and present a diagnostic challenge. Venous aneurysms in general are uncommon pathologic entities with a diverse etiology; the current etiologic concepts and classification are briefly discussed in the text. A new differential diagnosis for masses in the popliteal fossa is introduced by this report.

Unusual complication of Swan-Ganz catheter requiring mediastinotomy.

We were consulted to assist in the removal of an anchored Swan-Ganz catheter. After failing in several attempts to remove the catheter, we elected to return the patient to the operating room in the event that the catheter had been sutured to the right atrium. No evidence of this was found. We believe the catheter was anchored to the pulmonary bed, but the definite cause of this problem is still obscure.