Deep topical fornix nerve block versus peribulbar block in one-step adjustable-suture horizontal strabismus surgery.

BACKGROUND: We compared the efficacy of deep topical fornix nerve block anaesthesia (DTFNBA), which does not paralyse the extraocular muscles, with peribulbar block in patients undergoing one-step adjustable-suture horizontal strabismus surgery. Patients with a vertical, oblique squint were excluded from the study. METHODS: We studied 100 patients, allocated randomly to two groups. Group 1 (n=50) received peribulbar block with 5 ml of 1:1 mixture of 0.5% plain bupivacaine and 2% lignocaine supplemented with hyaluronidase 300 i.u. ml(-1). Group 2 (n=50) received DTFNBA with placement of a sponge soaked in 0.5% bupivacaine deep into the conjunctival fornices for 15 min. No sedation was given to either group. Analgesia was assessed by direct questioning of patients during the procedure. A three-point scoring system was used (no pain = 0, discomfort = 1, pain =2). If the pain score was 1, the patient was asked to look in the opposite direction to decrease the tension on the periosteal attachment of the muscle to relieve discomfort. If the pain score was 2 at any stage of the operation, general anaesthesia was given. RESULTS: In Group 2, significantly more patients (15) experienced discomfort than in Group 1 (no patients) (P<0.05), but general anaesthesia was not needed. CONCLUSIONS: DTFNBA is a useful technique for intraoperative adjustable-suture strabismus surgery. It does not alter muscle tone, thus allowing the surgeon to adjust the muscle sutures intraoperatively, and reducing the incidence of under- or over-correction of the squint in the immediate postoperative period.

Prospective evaluation of deep topical fornix nerve block versus peribulbar nerve block in patients undergoing cataract surgery using phacoemulsification.

We compared the efficacy of deep topical fornix nerve block anaesthesia (DTFNBA) versus peribulbar nerve block in patients undergoing cataract surgery using phacoemulsification. We studied 120 patients, allocated randomly to two groups. Group 1 (n = 60) received peribulbar block with 5 ml of a 1:1 mixture of 0.5% plain bupivacaine and 2% lidocaine supplemented with hyaluronidase 300 i.u. ml-1. Group 2 received DTFNBA with placement of a sponge soaked with 0.5% bupivacaine deep into the conjunctival fornices for 15 min. No sedation was given to either group. Analgesia was assessed by the reaction to insertion of the superior rectus suture and by questioning during the procedure. A three-point scoring system was used (no pain = 0, discomfort = 1, pain = 2). Scoring was repeated at keratotomy, hydrodissection and hydrodelineation, phacoemulsification, irrigation and aspiration, and at intraocular lens insertion. If the patient's pain score was 0 or 1, no further action was taken. If the pain score at any stage of the operation was 2, intracameral injection of 1% preservative-free lidocaine was given. One patient in Group 2 needed intracameral lidocaine at the stage of phacoemulsification (P > 0.05) and four experienced discomfort at irrigation and aspiration (P = 0.043). We conclude that DTFNBA may be a useful needle-free anaesthetic technique in patients undergoing cataract surgery using phacoemulsification.

Trypanosoma cruzi infection associated with Chagas' heart disease in humans in South Trinidad - abstract

Human infection with Trypanosoma cruzi, the aetiological agent of chagas' heart disease, is believed to be sporadic or non-existent in Trinidad. This study was undertaken to investigate whether human infection with T. cruzi occurs in Trinidad and whether this infection is associated with chagas' heart disease. Peripheral blood was withdrawn aseptically from 192 cardiac patients seen at the General Hospital, San Fernando from May to August, 1992. Sera were tested for T. cruzi IgG antibodies by an ELISA test and Giemsa-stained thick and thin smears of fresh blood examined for trypomastigotes of T. cruzi. Following physical examination, chest X-ray and 12-lead ECG, patients with findings consistent with ischaemic heart disease, hypertension, vavular heart disease, cardiomyopathy, diabetes, alcoholism, cigarette smoking and blood cholesterol > 220 mg/dl were excluded from further study. The remaining patients were subjected to echocardiography. Seventy-two (37.5 per cent) were positive for T. cruzi antibodies and 49 (68 per cent) of these had T. cruzi trypomastigotes in peripheral blood. After further review of 37 of these 49 seropositive parasite-positive patients, 12 were excluded on the basis of findings compatible with other cardiac diseases. Apical aneurysm, a cardinal sign of Chagas' disease, was found in the left and/or right ventricle of the heart in 21 patients. Our results present conclusive evidence that T. cruzi infection occurs in humans in Trinidad and that this infection is associated with cardiac pathology consistent with that of Chagas' heart disease (AU)

Depressed neutrophil chemotactic stimuli in supernatants of ionophore-treated polymorphonuclear leukocytes from selenium-deficient goats.

The effect of dietary selenium (Se) deficiency on the generation of neutrophil chemotactic factors from goat polymorphonuclear leukocytes (PMN) was studied. Polymorphonuclear leukocytes were isolated from 2 groups of crossbred goats. One group (n = 3) was fed a diet deficient in Se; the other (n = 3) was fed a diet adequate in Se. The PMN from each goat were stimulated with calcium ionophore A23187 and supernatants were collected. Each supernatant was immediately assayed for its ability to elicit neutrophil chemotaxis (NCT) and neutrophil chemokinesis by the Boyden chamber technique and neutrophil chemiluminescence (NCL) by the luminol-dependent chemiluminescence assay. Measurements from each group were compared, using the Student's t test. There was no significant difference (P greater than 0.01) in neutrophil chemokinesis elicited by supernatants derived from stimulated PMN from the 2 groups. However, supernatants derived from PMN of goats fed the Se-deficient diet had a significantly decreased capacity (P less than 0.01) to stimulate NCT and NCL. In vitro incubation of PMN with Se before ionophore treatment produced supernatants with increased NCL stimulation (P less than 0.05), but none with increased NCT stimulation (P greater than 0.05). However, both activities were restored after goats fed the Se-deficient diet (P less than 0.01) were given Se subcutaneously. Seemingly, dietary Se deficiency is associated with depressed PMN generation of factors that stimulate NCT and NCL. In contrast to NCL factors, synthesis of factors stimulating NCT probably was not associated directly with PMN glutathione peroxidase concentration.

The effect of selenium deficiency in goats on lymphocyte production of leukocyte migration inhibitory factor.

The effect of dietary selenium on caprine leukocyte migration inhibitory factor (LMIF) production was examined in vitro using lymphocytes from goats fed a diet deficient in selenium. Selenium deficiency was determined by decreased plasma glutathione peroxidase (GSH-Px). The ability of peripheral blood lymphocytes to produce LMIF induced by concanavalin A (Con A) was significantly (P less than 0.05) inhibited when cells from selenium-deficient and selenium-adequate goats were compared. In contrast, no significant (P greater than 0.05) differences were found between lymphocytes from selenium-deficient and selenium-adequate goats for Interleukin-2 (IL-2) production and blastogenesis induced by Con A. These data suggest that selenium deficiency may selectively impair LMIF production and hence the ability of lymphocytes to modulate neutrophil migration.

Effects of selenium on polymorphonuclear leukocyte function in goats.

Polymorphonuclear neutrophils (PMN) from goats fed selenium-deficient and selenium-adequate diets were tested for their ability to perform (i) random migration under agarose, (ii) leukotaxis toward serum chemotaxins under agarose, and (iii) phagocytosis of opsonized zymosan by chemiluminescence analysis. Function of PMN from goats fed the selenium-deficient diet was severely depressed, and incubation of these cells with selenium resulted in marked functional enhancement. Also, administration of selenium to goats fed the selenium-deficient diet resulted in increased PMN functions. Increase or decrease in PMN function was associated with corresponding alterations in blood, serum, and intracytoplasmic PMN glutathione peroxidase activities. It was concluded that a selenium-inadequate diet fed to goats results in depressed PMN function which is associated with physiologic changes in glutathione peroxidase levels.