Perturbation of the blood-retinal barrier after enzyme perfusion. A cytochemical study

The retina is protected from circulating molecules by a blood-retinal barrier. This is comprised of the impermeable apical-lateral junctions of the retinal pigment epithelium and intraretinal blood vessels lined by endothelia that have impermeable junctions and vesicles that do not transport material from the luminal to abluminal front. This study examined the effect of enzyme digestion upon the restrictive properties of the retinal capillary endothelium. Rats were perfused first with enzymes and then by hemoglobin that was visualized by ultrastructural cytochemical methods. After perfusion of buffer alone or buffers containing neuraminidase or heparinase, the cytochemical reaction product was confined to the capillary lumina and to endothelial cell vesicles facing the luminal front. In contrast, after heparitinase or pronase perfusion, reaction product filled the extravascular spaces. Chains of endothelial cell vesicles and patent transendothelial channels were often encountered. Endothelial cell junctions did not appear to be affected by enzyme treatment. These findings indicate that a cell-surface heparan sulfate proteoglycan (or a nonidentified protein removed by proteolysis) is a key molecule required for the maintenance of the blood-retinal barrier.     

Histomorphometric evaluation of intrahepatic changes following portal overflow in the rat.

Intrahepatic changes after an end-to-side renoportal arteriovenous shunt were studied in 60 rats. Portal and vena caval pressures did not increase from 3 weeks to 1 year. The number and diameters of the portal and hepatic vein lumens were determined through morphometric evaluation to calculate the relative areas. The proportion of area composed by the portal veins increased 3 weeks after shunt creation (P less than 0.001), reaching its highest level at 1 year (0.08% in control rats vs. 2.45% +/- 0.1% at 1 year). The proportionate area for hepatic veins also increased after 3 weeks (P less than 0.001), reaching its highest value by 12 weeks (0.49% in controls vs. 1.73% +/- 0.08% at 12 weeks). Our results suggest that there was a dramatic drop in the intrahepatic vascular resistance, especially at the portal bed, which may have compensated for the portal overflow. The theories regarding forward overflow compensatory mechanisms are discussed.     

Copper, Zinc and Lead Bioaccumulation in Marine Snail, Strombus gigas, from Guacanayabo Gulf, Cuba

Levels of copper, zinc and lead were determined in sediments and edible muscle of marine snail Strombus gigas collected from Guacanayabo Gulf, Cuba. The concentration range of each metal in marine snail muscle on mg kg⁻¹ wet weight varied as follows: Cu = 6.4–32.6, Zn = 20.4–31.1 and Pb = 0.2–2.3; and in corresponding sediments (on mg kg⁻¹ dry weight) as: Cu = 157–186, Zn = 56–94 and Pb = 20–37. The average biota-sediment accumulation factors (BSAFs) obtained for studied metals are less than unity in all cases, indicating that only a little fraction of metal content in the sediments is bioavailable, independently of their possible enrichments in the sediments. The concentrations of copper and lead in some of the marine snails are above typical public health recommended limits.     

Replacement of upper esophagus: Results with myocutaneous flap and with gastric transposition

The authors reviewed 25 cases of pharyngoesophageal replacement. A tubed pectoralis major myocutaneous flap was employed in ten cases where an adequate distal resection margin could be obtained above the thoracic inlet. Total gastric transposition was used in 15 cases where resection extended into the mediastinum. The overall rates of complications (52%), postoperative mortality (20%), and satisfactory deglutition (80%) were similar for both operations and were superior to those achieved with reconstructive procedures previously used by the authors. The choice of method is influenced by the length of the pharyngoesophagus to be replaced and the general condition of the patient. Gastric transposition is a more versatile operation and is adaptable to replacement of the entire esophagus if necessary, while the tubed pectoralis major myocutaneous flap has proven particularly effective for the rehabilitation of elderly and severely debilitated patients.     

Thymectomy in myasthenia gravis via original video-assisted infra-mammary cosmetic incision and median sternotomy: long-term results in 180 patients

Objective: The clinical outcome of 180 non-thymomatous myasthenia gravis (MG) consecutive cases surgically treated is reported herein. The original surgical access, consisting of a video-assisted infra-mammary cosmetic incision and median sternotomy, has originally been designed and described by our group. Methods: The in-hospital patients’ charts and the outpatients’ clinic follow-up information of the 180 cases have been extensively reviewed. In addition to the strictly surgical benchmark referral, data on the rate of cure of the MG (complete stable remission – CSR; pharmacological remission – PR) as indicated by the Myasthenia Gravis Foundation of America (MGFA) have been analysed as recorded at the 12 months after surgery checkpoint. Cosmetic outcome was evaluated as well. Results: Female to male ratio was 156 (86.7%):24 (13.3%). Mean age: 29.1 ± 10.9 years. Preoperative MGFA score: stage I: 4 patients (2.2%); IIa: 57 (31.7%); IIb: 32 (17.8%); IIIa: 41 (23.3%); IIIb: 42 (23.3%); IVa: 2 (1.1%); V: 2 (1.1%). Median operative time was 110 min (70–130 min) and median postoperative hospital stay was 4 days (3–10 days). Postoperative mortality was nil and morbidity occurred in seven patients (3.8%). Final pathology was consistent with: 146 hyperplastic thymus (81.1%); 28 involuted thymus (15.6%) and 6 normal thymus (3.3%). Ectopic thymic tissue was found in 68% of the patients. Mean follow-up was 62.9 ± 34.6 months. A CSR was obtained in 55%; PR in 18.3%; improvement in 39.9%, unchanged in 3.5%, worse in 1.1% and died in 0.5%. Kaplan–Meier estimates of CSR were 34.1% and 75.8% at 5 and 10 years, respectively. The preoperative therapy was the only parameter significantly associated with Kaplan–Meier CSR rates (univariate analysis – p < 0.001). Remarkably, 171 (95%) patients judged their cosmetic results to be excellent or very good. Conclusions: Thymectomy in MG patients via video-assisted infra-mammary cosmetic incision and median sternotomy has shown to be a useful surgical approach as demonstrated by the good functional and very good aesthetic results, associated with a very low morbidity and no mortality. Patients with preoperative mono-therapy have higher CSR rates. CSRs are durable, as the CSR rate improves with extended follow-up.     

The surgeon's attitude to malignant lymphomas of the breast. Analysis of eight cases

Eight cases of malignant lymphomas of the breast were considered. The age of the patients ranged from 26 to 57 years. All the cases were staged according to the Ann Arbor classification system; the distribution was 2 Ie, 2 IIe, 1 IIIe and 3 IVe. Surgery was limited to excisional biopsy in all patients, one of whom had been operated on elsewhere. Six patients had radiotherapy following limited surgery. All of them received chemotherapy. The treatment resulted in complete local control of the disease in all cases and only 2 patients died from disseminated disease. Six patients were alive and free of disease from 34 to 84 months after the diagnosis. Our experience and analysis of the literature allow us to conclude that the role of surgery in the diagnosis and treatment of malignant lymphomas with breast involvement should be limited to removal of the nodule, when possible, or to incisional biopsy in the case of massive involvement of the breast. In effect, aggressive surgery with a radical aim is not presently justified; in contrast, systemic chemotherapy should always be administered.     

Toxicidad en el intestino delgado inducida por 5-fluorouracilo en un paciente con carcinoma colorrectal

5-Fluorouracil-induced gastro-intestinal toxicity predominantly affects the upper and the lower gastro-intestinal tract. Although 5-fluorouracil (5-FU) can cause severe small-bowel toxicity, this has been reported only in 6 patients with colon carcinoma receiving 5-FU-based therapy. The presentation was extensive ulceration and inflammation of the small bowel with no involvement of the colon. We report another case of this toxicity, and discuss the diagnosis and mechanisms by which 5-FU can induce small-bowel toxicity.     

SMART—An Integrated Wireless System for Monitoring Unattended Patients

Monitoring vital signs and locations of certain classes of ambulatory patients can be useful in overcrowded emergency departments and at disaster scenes, both on-site and during transportation. To be useful, such monitoring needs to be portable and low cost, and have minimal adverse impact on emergency personnel, e.g., by not raising an excessive number of alarms. The SMART (Scalable Medical Alert Response Technology) system integrates wireless patient monitoring (ECG, SpO₂), geo-positioning, signal processing, targeted alerting, and a wireless interface for caregivers. A prototype implementation of SMART was piloted in the waiting area of an emergency department and evaluated with 145 post-triage patients. System deployment aspects were also evaluated during a small-scale disaster-drill exercise.     

An experimental model for the study of hepatic transport and metabolism of toxic compounds.

The usefulness of isolated liver cells for the study of hepatocellular transport and metabolism is demonstrated, using 1-naphthol and 2,2'-dichlorobiphenyl as model compounds. More than 60% of both substances is rapidly taken up by the cells. Naphthol is conjugated with sulphate and with glucuronic acid. These conjugates are released from the cells. Conjugation of dichlorobiphenyl and release of the conjugates is about 25 times slower than that of naphthol.