Hepatic interstitial laser photocoagulation. An investigation of the relationship between acute thermal lesions and their sonographic images.

OBJECTIVES: The relationship between hepatic interstitial laser photocoagulation (ILP) lesions and their acute ultrasound images was evaluated. In addition, the natural history of ILP lesions in normal pig liver was documented. METHODS: Eighteen pigs underwent laparotomy and ultrasound-monitored ILP. In part 1 of the study, 12 pigs each had four separate exposures (1.50 W for 60, 100, 300, and 500 seconds) and were divided into four groups according to when they were killed (0, 3, 7, and 21 days). In part 2 of the study, six pigs each had two sequential exposures (1.60 W for 1,000 and then 500 seconds) at separate hepatic sites. Survival time was 3 days. Necropsy and histologic examination were performed in all animals. In 0- and 3-day survivors, actual thermal lesions were compared with "early" (immediately after ILP) and "late" (1 hour after ILP) ultrasound images. RESULTS: In the 300-, 500-, and 1,000-second exposures of parts 1 and 2, thermal lesions were overestimated or approximated by early ultrasound and were underestimated or approximated by late ultrasound. Analysis of variance showed statistically significant differences between thermal lesions and their early and late ultrasound images (F = 18.6, P < .001, no interactions). Time-growth characteristics of ILP lesions were reasonably consistent on ultrasound; exceptions were identifiable 200 seconds into the exposure. In part 2, ultrasound changes were minimal in five of six 500-second (second sequential) technically satisfactory exposures. Thermal lesions were seen at necropsy. All lesions healed by formation of granulation tissue and collagen. CONCLUSIONS: During ILP, early ultrasound images frequently overestimate actual thermal lesions. Ultrasound-monitored ILP of tumors may be most effective if, on early ultrasound, echogenic changes extend beyond the tumor margins. Late ultrasound images underestimate or approximate thermal lesions. Their value in clinical ILP should be investigated. It is unclear why ultrasound images of proven thermal lesions were not seen during 5 of 6 otherwise satisfactory 500-second ILP exposures performed immediately after 1,000-second exposures.

Sonographic changes during hepatic interstitial laser photocoagulation. An investigation of three optical fiber tips.

RATIONALE AND OBJECTIVES: Interstitial laser photocoagulation (ILP) destroys tumors thermally, using laser energy delivered from implanted optical fibers. The objectives of the study are to identify a fiber tip/delivered energy combination which produces lesions of useful size, visible on ultrasound (US) during ILP, and to compare ILP lesions and their US images. METHODS: Hepatic ILP was performed at laparotomy in six pigs, using three different fiber tips (cylindrical diffusing, spherical diffusing, plane-cut). US images were obtained during ILP, immediately after ("early" images), and before the animals were killed (2-2.5 hours, "late" images). Actual lesions were assessed histopathologically. RESULTS: Few US changes were seen around cylindrical diffusing and spherical diffusing tips until tip destruction. Plane-cut tips, at 1.5 to 2.0 W, produced prominent US images of the 1- to 2-cm thermal lesions. Early images tended to overestimate necrosis. Late images approximated necrosis. CONCLUSION: For US-controlled ILP, plane-cut tips are better than currently available cylindrical diffusing or spherical diffusing tips. Lesion image growth periods might enable control of lesion size. Further studies are needed to determine the consistency of the described relationship between lesion images and actual lesions.

Benign biliary cystadenoma.

Biliary cystadenomas and cystadenocarcinomas are rare. They arise in the liver or, less frequently, from the bile ducts. The characteristic appearance of these lesions in computed tomography and ultrasonography scans, as observed in a 26-year-old woman, is described. The features are similar to those of hydatid disease, and without travel history and the results of stool cultures and serologic tests differentiation may be impossible. Other considerations in the differential diagnosis are also discussed. Surgery is always indicated, because benign and malignant tumours in this area cannot be differentiated radiologically.

The normal esophagus.

The diagnosis of diseases affecting the esophagus frequently depends on a knowledge of the normal anatomy and histology of the esophagus. This paper describes and relates normal esophageal gross and histological features to pathological conditions affecting the esophagus. Special attention is given to the problems of diagnosis encountered when confronted with mucosal biopsy specimens from the gastroesophageal junction.

S-100 protein antibodies do not label normal salivary gland myoepithelium. Histogenetic implications for salivary gland tumors.

Neoplastically modified myoepithelial cells have a key role in developing the histologic characteristics of some salivary gland tumors. S-100 protein expressed in certain of these tumors is suggested to support this role, as the principal component in the human salivary gland reported to be S-100 protein-positive is myoepithelium. Confirmation of such an important aspect is required. Immunoperoxidase staining of parotid salivary gland shows considerably different patterns obtained with antibodies to S-100 protein, neuron-specific enolase, and neurofilaments compared with those for muscle-specific actin and cytokeratin 14; many more cells and their processes associated with acini and ducts are evident with the latter two antibodies. Double immunofluorescent staining with antibodies to either S-100 protein or neuron-specific enolase combined with muscle-specific actin does not reveal colocalization of these antigens in myoepithelial cells. The former localize only to nerve fibers adjacent to, but separate from, acini, and the latter only to myoepithelial cells. It is apparent that S-100 protein staining of the rich network of unmyelinated nerves in the interstitial tissues, evident ultrastructurally, has been misinterpreted as myoepithelium. This result has important implications for histogenetic classifications of salivary gland tumors.

Primary adult lactose intolerance protects against development of inflammatory bowel disease.

We have compared the incidence of inflammatory bowel disease (IBD) to the prevalence of lactose malabsorption (LM) in several countries. Our observations indicate that IBD is rare where LM is highly prevalent. The correlation between incidence of Crohn's disease and LM is -0.93, p less than 0.01, the correlation between incidence of ulcerative colitis and LM is -0.89, p less than 0.01. We, therefore, propose that LM results in the formation of volatile fatty acids which may inhibit multiplication of potentially pathogenic organisms.