Clinical and histopathological outcomes of subconjunctival triamcinolone injection for the treatment of acute ocular alkali burn in rabbits.

PURPOSE: To evaluate the efficacy and safety of subconjunctival injection of triamcinolone in the treatment of acute ocular alkali burn in rabbits. METHODS: Two groups of 5 rabbits were subjected to alkali burn (1 N NaOH). One group was treated with 1 subconjunctival injection of 0.3 mL of triamcinolone and the other with 1 subconjunctival injection of 0.3 mL of 0.9% saline. The affected corneas were observed for vascularization and opacity approximately 10 minutes after the burn and also after 7, 14, and 21 days. Photographs were taken for observation and statistical analyses. At all time intervals, the corneas were classified according to predetermined scores. Twenty-one days after the treatment, the animals were anesthetized, and their eyes were enucleated and processed for histopathology. RESULTS: Greater vascularization and opacity appeared in the animals that were treated with saline than in those treated with subconjunctival triamcinolone (vascularization: 7 days, P = 0.0107; 14 days, P = 0.0099; and 21 days, P = 0.0088; opacity: 7 days, P = 0.0079; 14 days, P = 0.0112; and 21 days, P = 0.0255). These results were also compatible with the morphological and statistical analyses, which revealed a more intense inflammatory process in the group treated with saline (P = 0.0317). No complications, such as corneal melting, perforation, or infection, were observed. CONCLUSIONS: Subconjunctival injection of triamcinolone may be a therapeutic option for the treatment of acute ocular burn because it reduced the corneal inflammatory process, opacity, and vascularization, with no apparent clinical changes in the general state of the animal.

Trauma ocular: reconstituição da câmara anterior com tonômetro de não-contato / Ocular trauma: remake of anterior chamber with noncontact tonometer

Objetivo: Descrever a reconstituição da câmara anterior, ocorrida após tonometria de não-contato. Local: Serviço de Oftalmologia da Policlínica de Botafogo - Rio de Janeiro, Brasil. Método: Utilização do tonômetro de não-contato em ferida perfurante de córnea. Resultados: Preenchimento da câmara anterior com ar, evitando tratamento cirúrgico. Conclusão: Os autores acreditam que este procedimento, em princípio insólito, mereça ser relatado pois, futuramente a partir de estudos concretos, poderá ser utilizado em feridas de córneas com atalamia ou câmara anterior rasa.

Role of hypercholesterolemia in accelerated transplant coronary vasculopathy: results of surgical therapy with partial ileal bypass in rabbits undergoing heterotopic heart transplantation.

BACKGROUND: We tested the hypothesis that plasma cholesterol lowering action of partial ileal bypass (PIB) is beneficial in mitigating accelerated transplantation coronary vasculopathy. METHODS: Forty-one New Zealand white rabbits were randomized to receive a normal (n = 21) or 1% cholesterol diet (n = 20). They underwent heterotopic heart transplantation with sham-PIB (n = 19) or PIB (n = 22) and immunosuppression with cyclosporine A (CyA). RESULTS: CyA increased plasma cholesterol of rabbits receiving a normal diet. This effect was mitigated by PIB (101 +/- 50 mg/dl CyA vs baseline 24 +/- 8, p < 0.001; vs 54 +/- 25 mg/dl with PIB, p < 0.05). In cholesterol-fed rabbits, PIB decreased plasma cholesterol levels (520 +/- 236 mg/dl PIB vs baseline 720 +/- 359, p < 0.05; vs 1502 +/- 253 mg/dl with sham PIB, p < 0.00001). Coronary arteries (CA) of 21 5-week survivors were evaluated by light microscopy and digital morphometry. No rejection was noted. Histologic study revealed vasculopathy in 3% of 705 native and 18% of 654 transplant CA (p < 0.05). Graft vasculopathy (GV) was present in 25% of 365 CA of sham-PIB and 10% of 289 CA of PIB rabbits (p = 0.07). In cholesterol-fed rabbits, GV was characterized by fatty proliferative lesions in 75% of 91 pathologic CA of sham and 21% of 28 pathologic CA of PIB rabbits (p < 0.05). Graft intimal hyperplasia was not correlated with cholesterol intake or PIB and was present in 18 of 119 pathologic CA. CONCLUSIONS: GV was characterized by fatty intimal proliferation, fibrous intimal hyperplasia, and a "mixed type." Fibrous intimal hyperplasia developed in native and transplanted hearts, and CyA seemed to promote this state. Hypercholesterolemia promoted fatty proliferative lesions, worsening GV. PIB significantly decreased total cholesterol and retarded fatty proliferation of CA of native and transplanted hearts but did not prevent intimal hyperplastic vasculopathy. Therapy of hypercholesterolemia is recommended to at least mitigate the fatty intimal proliferation of GV.

Prosthetic mitral valve replacement: late complications after native valve preservation.

Preservation of the mitral valve leaflet and tensor apparatus during valve replacement is believed to maintain left ventricular performance. The routine use of this technique may lead to left ventricular outflow or inflow obstruction as illustrated in the present report. We recommend mobilization or excision of the anterior mitral valve leaflet and preservation of the posterior leaflet if replacement of the valve is contemplated for incompetence.

Physician understanding of the National Practitioner Data Bank.

National Practitioner Data Bank (NPDB) reports are part of the process for acquiring staff privileges, professional credentials, and licenses throughout a physician's entire career. We surveyed our hospital's 66 residents to assess their understanding of NPDB. Only 9 residents had heard about NPDB. A follow-up survey of the 10 medical schools in Pennsylvania and Maryland showed just 4 schools covered NPDB in their curricula. Finally, we did a third survey--of 1,410 Pennsylvania Medical Society members. Eighty-one percent did not know that denial of initial license application was not a reportable offense; 69% did not know that voluntary entrance into alcohol/drug rehabilitation was not reportable; and 75% did not know that denial of expanded privileges because of level of clinical competence was reportable. Only 13% knew how to obtain their files. Our surveys suggest physicians have a poor understanding of NPDB even though these reports could have career-jeopardizing implications, especially if the Clinton administration expands access to NPDB.

Transperitoneal absorption of thermocautery-induced carbon monoxide formation during laparoscopic cholecystectomy.

Carbon dioxide pneumoperitoneum (PP) during laparoscopic cholecystectomy (LC) causes hypercapnia and acidemia. Thermocautery carbon monoxide formation during LC was studied in 15 patients. CO samples were read by electrochemical sensor as parts per million (ppm) and obtained intraperitoneally at PP, gallbladder takedown (GBTD), and exhalation. In blood, CO was measured by spectrophotometry as percentage of carboxyhemoglobin (HbCO) during anesthesia induction, at end of PP, at GBTD, and in the recovery room. Heart rate, mean arterial pressure, oxygen saturation, and end-tidal CO2 were followed prospectively. Data were analyzed by analysis of variance and Student's t test. In 35 min, thermocautery increased intraperitoneal CO from 4.7 +/- 3.8 ppm at baseline to 326 +/- 360 ppm at GBTD (p < 0.004). HbCO increased from PP to GBTD (0.7 +/- 0.6 vs. 1.2 +/- 0.7%; p < 0.01). Thermocautery produces high levels of CO intraperitoneally, which are absorbed into the circulation. Exposure time is short, which may explain the lack of hemodynamic and oxygenation changes.

Results of the unidirectional Centri-Safe arterial valve for prevention of retrograde flow during cardiopulmonary bypass.

Retrograde blood from the aortic cannula into the cardiopulmonary circuit may lead to aortic air emboli when nonocclusive centrifugal pumps are used. The authors tested a nonregurgitant, unidirectional valve containing a Teflon ball occluder to prevent backflow. In vitro measurements of leakage rate, forward flow pressure drop, burst strength, and hemolysis levels along with animal (n = 12) and human (n = 12) in vivo hematologic and hemolysis levels were measured. Data were analyzed by paired and unpaired Student's t-test. Pressure drop differences at flows of 5 l/min were 7.3 +/- 0.3 mmHg before and 7.6 +/- 0.1 mmHg after 10,800 cycles of pulsatile pumping. (P = NS). Leakage rate during this period at pressures of 100 mmHg was not significant. Volume required to close the Teflon ball was less than 1 ml. Hemolysis analysis done in vitro and in vivo in control (no valve) and experimental (valve) groups used hemoglobin, hematocrit, platelets, plasma free hemoglobin, and lactic dehydrogenase as hemolysis indices. There were no statistical differences. The authors conclude that the CentriSafe valve (Cardiac Systems, Inc., Conshohocken, PA) is safe and prevents fatal backflow and air emboli. The valve is nonthrombotic in anticoagulated blood, can be opened and closed thousands of times, and has a burst strength equal to or greater than other components in the perfusion setup.

New technique for coronary sinus cannulation using a fiberoptic stylet.

Fluoroscopy, echocardiography, blind digital approach, and direct visual insertion have been used for retrograde cannulation of the coronary sinus. We cannulate the coronary sinus by transillumination using a standard flexible retroplegia cannula with a reusable fiberoptic stylet designed by our open heart program. An attachable light source illuminates the tip, which is guided into the coronary sinus ostium. We have used the technique in 16 patients who could not be cannulated with the blind digital method.

Repair of multiple mycotic aortic aneurysms in a newborn.

Thoracoabdominal aortic and common and internal iliac artery mycotic aneurysms resulted from an umbilical arterial catheter in a 3 1/2-week-old boy. He underwent staged repair including an 8-mm Gore-tax tube graft, primary repair of the common iliac artery aneurysm, and resection of the internal iliac aneurysm. His operative and postoperative course was uneventful. He was asymptomatic at 17 months' follow-up, with equal blood pressure in the upper and lower extremities. Magnetic resonance imaging showed no stenoses or recurrent aneurysms at the anastomotic sites of the Gore-tex tube graft. Blood supply to his left leg came from collaterals, principally a large crossing vessel from the right iliac artery. This case represents the first successful aortic replacement in a 5 week old with extensive involvement of the thoracoabdominal aorta and its branch vessels.

Natural history of atherosclerosis and hyperlipidemia in heterozygous WHHL (WHHL-Hh) rabbits. II. Morphologic evaluation of spontaneously occurring aortic and coronary lesions.

This study evaluated the morphologic appearance of spontaneous aortic and coronary atherosclerotic lesions in 21 of the 28, 3-year old, heterozygous Watanabe heritable hyperlipidemic (WHHL-Hh) rabbits whose lipid profiles were presented in part I of this report. In situ perfusion fixation of the arteries showed 100% of the aortas involved with one or another type of intimal lesion. In male rabbits (n = 13), the abdominal aortas had more severe fibrosis and more diffuse intima thickening than the thoracic aortas, (p < 0.001). In female rabbits (n = 8), fatty streaks and fibrous lesions were more predominant in the thoracic than in the abdominal aorta (p < 0.05). Fatty aortic plaques in the female were more commonly found in the abdominal than in the thoracic aorta, but this finding was not statistically significant. In contrast, fatty aortic plaques were not found in the male aortas; however, larger areas of diffuse intimal thickening with fatty deposits were more common in the abdominal aortas of the males (p < 0.01). Annular arteriosclerotic lesions, exclusive to the thoracic aorta, occurred in three of 21 rabbits. Histologically, the aortas demonstrated subintimal fibrosis, fragmentation of the lamina elastica interna, focal medial degeneration, and cholesterol clefts. The coronary arteries were involved in 85% of the males and in 86% of the females. Lesions were more common in the left than in the right coronary artery and primarily consisted of mild nonobstructing intimal hyperplasia with fibrosis. Based on these observations, we consider older WHHL-Hh rabbits excellent models for studying atherosclerosis. Because of their genetic and age-related lesions, WHHL-Hh rabbits may be superior to the cholesterol-fed rabbit model with respect to comparability with human atherosclerotic lesions.

Natural history of atherosclerosis and hyperlipidemia in heterozygous WHHL (WHHL-Hh) rabbits. I. The effects of aging and gender on plasma lipids and lipoproteins.

Plasma lipid and lipoprotein levels are influenced by physiologic changes during the life span of mammalian organisms. In the present study, the effects of aging and gender on plasma lipids and lipoprotein cholesterol fractions in heterozygous Watanabe heritable hyperlipidemic (WHHL-Hh) rabbits were examined. For 3 years the rabbits were fed regular rabbit chow and were free from any experimental manipulation. Male WHHL-Hh rabbits (n = 17) had a 55% increase in total plasma cholesterol level (p < 0.005) between the ages of 7.5 and 34 months. This increase was due to significant increases in very low-density lipoprotein cholesterol (VLDL-C) (28%, p < 0.05), in low-density lipoprotein cholesterol (126%, p < 0.005), and in high-density lipoprotein cholesterol (28%, p < 0.05). Female WHHL-Hh rabbits (n = 11) did not show significant differences in lipid plasma values with aging. However, their plasma values, with the exception of the VLDL-C, were significantly (p < 0.05) higher than those of the male rabbits. Pregnancy and increased weight in the older female rabbits may have accounted for these differences. Significant plasma lipid changes occur as a function of heterozygosity, age, and gender in WHHL-Hh rabbits. The lipoprotein changes seen in male but not in female WHHL-Hh rabbits during the aging process are similar to those observed in human subjects. Pregnancy in WHHL-Hh rabbits, like in human beings, may induce hyperlipidemia, which is opposite to the effects observed in normal rabbits or homozygous WHHL rabbits.

Septate gallbladder with cholelithiasis: a cause of chronic abdominal pain in a 6-year-old child.

This report describes the case of a 6-year-old girl with septate gallbladder and cholelithiasis without cholecystitis, an uncommon condition associated with chronic abdominal pain. The absence of smooth muscle components within the gallbladder septae supports an embryogenic abnormality that may have occurred early during the maturation of the gallbladder lumen. In concert with other predisposing factors, the septa may have induced gallstones and, thus, the patient's symptoms. Although rare, gallbladder abnormalities may cause abdominal pain in children and should be included in the differential diagnosis. Early ultrasound should be obtained as part of a workup if gallbladder abnormalities are suspected. Elective cholecystectomy is curative.

Low plasma lipid levels and increased cholesterol synthesis after partial ileal bypass plus lovastatin in hypercholesterolemic rabbits.

Partial ileal bypass (PIB) lowers the plasma total cholesterol (C) level, thereby increasing hepatic C synthesis to replenish bile acid and C stores. Lovastatin, a C synthesis inhibitor, may act as a potential adjuvant to PIB for lipid lowering. In this study, the effects of PIB and lovastatin, alone and in combination, were examined in plasma and tissue. For 14 weeks, 32 New Zealand White rabbits received a C-free, alfalfa-free, natural-ingredients diet previously shown to induce hypercholesterolemia. The rabbits were divided into control, lovastatin, PIB, and PIB plus lovastatin groups. Lovastatin was administered at a dose of 0.35 mg/kg twice daily. Compared with the control group, PIB alone decreased the plasma total C level by 75% (p less than 0.005), the low-density lipoprotein (LDL)-C level by 79% (p less than 0.025), and hepatic C content by 50% (p less than 0.05), while increasing hepatic C synthesis by 176% (p less than 0.05). Compared with the control group, lovastatin alone decreased the plasma total C value by 36% (p = NS), the LDL-C level by 35% (p = NS), hepatic C content by 29% (p = NS), and hepatic C synthesis by 52% (p = NS). Compared with the control group, the combination of PIB and lovastatin decreased the plasma total C level by 78% (p less than 0.005), the LDL-C level by 74% (p less than 0.025), and hepatic C content by 58% (p less than 0.05); however, the hepatic C synthesis increased by 490% (p less than 0.005) compared with the control group and by 110% (p less than 0.05) compared with PIB alone. This is the first demonstration of a metabolic reversal of the cholesterol synthesis inhibition engendered by lovastatin. We conclude that both PIB and lovastatin lower plasma total C and lipoprotein C fractions. Their combination has an additive C-lowering effect in plasma and decreases tissue C content by increasing cellular C demand. This latter effect overcomes the inhibitory effect of lovastatin on hepatic C synthesis, resulting in an augmented compensatory increase in hepatic C synthesis.

Synergistic lipid-lowering effects of alfalfa meal as an adjuvant to the partial ileal bypass operation.

Partial ileal bypass (PIB) and ingestion of alfalfa are both known to lower plasma cholesterol (C) levels. During an 18-week period, the combined effects of both were studied in four randomized groups of rabbits receiving C-free, hypercholesterolemia-inducing, semisynthetic diets 3 weeks after sham or PIB surgery. The diets, with or without alfalfa, had similar overall compositions of fat, protein, carbohydrate, and fiber. We measured blood C, triglycerides (T), and lipoprotein fractions of both C and T at biweekly intervals. In vivo liver and small-bowel synthesis of C, fatty acids (FA), and nonsaponifiable lipids (NSL) were determined with radioactive 14C-acetate at the end of the study. The results were evaluated by means of analysis of variance using unweighted cell means. The combined PIB and alfalfa modalities significantly lower C levels in serum, plasma, low-density lipoproteins, and high-density lipoproteins by 66%, 71%, 85%, and 35%, respectively. However, due to alfalfa, a significant increase of 49% was observed in plasma T when both treatments were combined. Liver FA synthesis was significantly decreased (65%) with PIB and increased (161%) with alfalfa; when the two treatments are combined, a nonsignificant response was observed. Similarly, this inverse relationship for PIB and alfalfa was seen for C and NSL synthesis. Small-bowel FA synthesis was significantly decreased (72%) by the combination of PIB and alfalfa. We conclude that alfalfa suppresses, in part, the physiologic rebound effect of PIB surgery by increasing hepatic C and NSL synthesis; inversely, PIB surgery inhibits the additive effect in the liver synthesis of FA produced by alfalfa. Alfalfa and PIB alone, and synergistically, decrease total small-bowel lipid synthesis, specifically that of FA. Alfalfa is an effective adjuvant to PIB for reducing total and lipoprotein C fractions.

A rabbit model for implanting continuous drug infusion pumps.

This paper describes a surgical technique for implanting a readily available, human-sized drug infusion pump in rabbits. We developed this technique in order to expand uses of implantable infusion pump technology in the laboratory. The dog, which has been the research animal of choice in previous studies using implantable pumps, can now be replaced by smaller, less expensive animals for similar or other laboratory purposes. This technique can be of particular importance in the study of atherosclerosis where the dog is a poor model and the rabbit an excellent one. In 18 rabbits with inferior vena cava cannulations, we were able to obtain 100% survival and constant solution delivery for up to and greater than 6 months. This technique is safe and reproducible. By employing a simple catheter modification and using special pump anchoring precautions, we found that we could successfully use a human-sized device in rabbit studies. Commentary is also made concerning the relative contributions to patency and vein sclerosis of catheter diameter and the infusate media.