Increased expression of type 2 3alpha-hydroxysteroid dehydrogenase/type 5 17beta-hydroxysteroid dehydrogenase (AKR1C3) and its relationship with androgen receptor in prostate carcinoma.

Type 2 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD) is a multi-functional enzyme that possesses 3alpha-, 17beta- and 20alpha-HSD, as well as prostaglandin (PG) F synthase activities and catalyzes androgen, estrogen, progestin and PG metabolism. Type 2 3alpha-HSD was cloned from human prostate, is a member of the aldo-keto reductase (AKR) superfamily and was named AKR1C3. In androgen target tissues such as the prostate, AKR1C3 catalyzes the conversion of Delta(4)-androstene-3,17-dione to testosterone, 5alpha-dihydrotestosterone to 5alpha-androstane-3alpha,17beta-diol (3alpha-diol), and 3alpha-diol to androsterone. Thus AKR1C3 may regulate the balance of androgens and hence trans-activation of the androgen receptor in these tissues. Tissue distribution studies indicate that AKR1C3 transcripts are highly expressed in human prostate. To measure AKR1C3 protein expression and its distribution in the prostate, we raised a monoclonal antibody specifically recognizing AKR1C3. This antibody allowed us to distinguish AKR1C3 from other AKR1C family members in human tissues. Immunoblot analysis showed that this monoclonal antibody binds to one species of protein in primary cultures of prostate epithelial cells and in LNCaP prostate cancer cells. Immunohistochemistry with this antibody on human prostate detected strong nuclear immunoreactivity in normal stromal and smooth muscle cells, perineurial cells, urothelial (transitional) cells, and endothelial cells. Normal prostate epithelial cells were only faintly immunoreactive or negative. Positive immunoreactivity was demonstrated in primary prostatic adenocarcinoma in 9 of 11 cases. Variable increases in immunoreactivity for AKR1C3 was also demonstrated in non-neoplastic changes in the prostate including chronic inflammation, atrophy and urothelial (transitional) cell metaplasia. We conclude that elevated expression of AKR1C3 is highly associated with prostate carcinoma. Although the biological significance of elevated AKR1C3 in prostatic carcinoma is uncertain, AKR1C3 may be responsible for the trophic effects of androgens and/or PGs on prostatic epithelial cells.

Loss of tissue transglutaminase as a biomarker for prostate adenocarcinoma.

BACKGROUND: Additional molecular tissue biomarkers for prostate carcinoma are needed to stratify patients with clinically suspicious findings, such as an elevated prostate specific antigen (PSA) with a negative biopsy, according to risk. METHODS: Prostate tissues from 43 cancer cases and 47 controls with no evidence of cancer were labeled for transglutaminase by immunohistochemistry. Immunoreactivity was quantified using the Autocyte Pathology Workstation. In addition, quantitative fluorescence image analysis was used to compare transglutaminase concentrations in cells obtained by fine-needle aspiration from excised prostates. Loss of gene expression was evaluated by reverse transcriptase-polymerase chain reaction and growth with 5-azacytidine. RESULTS: Visually, benign glands from controls generally expressed tissue transglutaminase, whereas regions with adenocarcinoma generally were negative. With quantitative immunohistochemistry, 41 of 43 adenocarcinoma of the prostate (CaP) cases expressed lower mean percentage areas positive for transglutaminase than did 30 of 30 benign prostatic hyperplasia (BPH) and 17 of 17 prostatitis cases (P < 0.0001; odds ratio [OR], 1577; 95% confidence interval (CI), 74-33, 820; relative risk [RR], 25; 95% CI, 6-95). Quantitative immunofluorescence of 3277 cells collected by FNA from 19 CaP cases and 645 cells from 5 cases of BPH showed that the mean content of transglutaminase was 93 femtograms (fg) for the CaP-derived cells and 138 fg for the BPH cells (P < 0.0001). Receiver operating curve analysis of the immunohistochemistry data showed an optimized threshold produced 95% sensitivity with 100% specificity. Growth of LNCaP cells with 5-azacytidine failed to stimulate transglutaminase expression, suggesting that loss of expression was likely not attributable to promoter methylation. CONCLUSIONS: Measurements of transglutaminase on tissue sections provides additional diagnostic information that is potentially useful for risk assessment of patients with suspicious clinical findings, such as nodules or positive PSA and negative biopsies, without overdetecting disease.

Ocular adnexal oncocytoma: a case series and clinicopathologic review of the literature.

The authors report the clinical, microscopic, and ultrastructural features of four oncocytic lesions involving the ocular adnexa. Three of the lesions originated in the ocular caruncle of elderly women, and a single case was encountered from the medial eyelid of an elderly man. Each lesion clinically presented as a slow-growing, painless, red mass. The histopathologic features were distinctive, with polyhedral cells containing granular eosinophilic cytoplasm found to consist of large numbers of mitochondria on ultrastructural examination. Of the 40 cases previously reported primarily in the ophthalmologic literature, the cases reported here similarly involved the eyelid and associated ocular adnexa with a predilection for elderly women. Oncocytomas probably represent an age-associated metaplastic and neoplastic transformation of the glandular epithelium comprising the ducts of salivary glands.

Inverse relationship between electrode size and lesion size during radiofrequency ablation with active electrode cooling.

BACKGROUND: Clinical efficacy has driven the use of larger electrodes (7F, length > or =4 mm) for radiofrequency ablation, which reduces electrogram resolution and causes variability in tissue contact depending on electrode orientation. With active cooling, ablation electrode size may be reduced. The purpose of this study was to examine the effect of electrode length on tissue temperature and lesion size with saline irrigation used for active cooling. METHODS AND RESULTS: In 11 anesthetized dogs, the thigh muscle was exposed and bathed with heparinized canine blood. A 7F ablation catheter with a 2- or 5-mm irrigated tip electrode was positioned perpendicular or parallel to the thigh muscle. Radiofrequency current was delivered at constant voltage (50 V) for 30 seconds during saline irrigation (20 mL/min) to 148 sites. Tissue temperature at depths of 3.5 and 7 mm and lesion size were measured. In the perpendicular electrode-tissue orientation, radiofrequency applications at 50 V with the 2-mm electrode compared with the 5-mm electrode resulted in lower power at 50 V (26 versus 36 W) but higher tissue temperatures, larger lesion depth (8.0 versus 5.4 mm), and greater diameter (12.4 mm versus 8.4 mm). Also, in the parallel orientation, overall power was lower with the 2-mm electrode (25 versus 33 W), but tissue temperatures were higher and lesions were deeper (7.3 versus 6.9 mm). Lesion diameter was similar (11.1 versus 11.3 mm) for both electrodes. CONCLUSIONS: The smaller electrode resulted in transmission of a greater fraction of the radiofrequency power to the tissue and resulted in higher tissue temperature, larger lesions, and lower dependency of lesion size on the electrode orientation.

Myofibroblastoma of the breast revisited: an etiologic association with androgens?

Myofibroblastoma of the breast is an uncommon benign stromal tumor encountered predominantly among elderly men. Histologically, myofibroblastoma is a well-circumscribed tumor comprised of bipolar spindle cells arranged in short fascicles traversed by collagen bundles. Based on previous histological, immunohistochemical, and ultrastructural observations, this tumor is thought to be derived from myofibroblasts. The pathogenesis of myofibroblastoma is unknown. Given the demographics of this lesion, the established trophic effect of steroid hormones, and the potential diagnostic utility of hormone receptor analysis in differentiating spindle cell tumors, we immunohistochemically tested for estrogen and androgen receptors in a host of spindle cell lesions including myofibroblastoma of the breast. Five cases reported herein of histological confirmed myofibroblastoma obtained from male and female breasts each showed strong nuclear antibody staining for the androgen receptor, not seen in four cases of leiomyosarcoma, three cases of fibromatosis, three cases of dermatofibrosarcoma protuberans, and two cases of monophasic synovial sarcoma. We postulate that the androgen receptor or its ligands may be pathologically related to the development of myofibroblastoma of the breast and diagnostically useful in differentiating it from other spindle cell lesions.

Fibronectin and the extracellular matrix in the perforating disorders of the skin.

Despite detailed microscopic descriptions and clinical observation, little is known regarding the pathogenesis of the perforating disorders of skin, which have traditionally been subdivided into numerous microscopic entities associated with various clinical settings. An increasing body of evidence now suggests that the perforating disorders of skin are akin, and may constitute an expanded single pathologic entity. Each of the classic perforating disorders of skin, including elastosis perforans serpiginosa, perforating folliculitis, reactive perforating collagenosis, Kyrle's disease, and perforating disorder of uremia, have been shown to extrude collagen, elastin, and related extracellular matrix components through the epidermis. Considering a shared pathogenic mechanism among these entities, we explored the possible role of the extracellular matrix, in particular fibronectin, in perforating disorders of skin. Using immunohistochemical and serum determinations of extracellular matrix constituents, including fibronectin, collagen type IV, laminin, and tenascin, we showed consistent serum elevation and/or deposition of fibronectin, in each case, without a commensurate increase in laminin, collagen type IV, and tenascin. We propose that elevated serum and tissue concentrations of fibronectin may be responsible for inciting, in a physiologically aberrant manner, increased epithelial migration and proliferation culminating in perforation.

Why a large tip electrode makes a deeper radiofrequency lesion: effects of increase in electrode cooling and electrode-tissue interface area.

INTRODUCTION: Increasing electrode size allows an increase in radiofrequency lesion depth. The purpose of this study was to examine the roles of added electrode cooling and electrode-tissue interface area in producing deeper lesions. METHODS AND RESULTS: In 10 dogs, the thigh muscle was exposed and superfused with heparinized blood. An 8-French catheter with 4- or 8-mm tip electrode was positioned against the muscle with a blood flow of 350 mL/min directed around the electrode. Radiofrequency current was delivered using four methods: (1) electrode perpendicular to the muscle, using variable voltage to maintain the electrode-tissue interface temperature at 60 degrees C; (2) same except the surrounding blood was stationary; (3) perpendicular electrode position, maintaining tissue temperature (3.5-mm depth) at 90 degrees C; and (4) electrode parallel to the muscle, maintaining tissue temperature at 90 degrees C. Electrode-tissue interface temperature, tissue temperature (3.5- and 7.0-mm depths), and lesion size were compared between the 4- and 8-mm electrodes in each method. In Methods 1 and 2, the tissue temperatures and lesion depth were greater with the 8-mm electrode. These differences were smaller without blood flow, suggesting the improved convective cooling of the larger electrode resulted in greater power delivered to the tissue at the same electrode-tissue interface temperature. In Method 3 (same tissue current density), the electrode-tissue interface temperature was significantly lower with the 8-mm electrode. With parallel orientation and same tissue temperature at 3.5-mm depth (Method 4), the tissue temperature at 7.0-mm depth and lesion depth were greater with the 8-mm electrode, suggesting increased conductive heating due to larger volume of resistive heating because of the larger electrode-tissue interface area. CONCLUSION: With a larger electrode, both increased cooling and increased electrode-tissue interface area increase volume of resistive heating and lesion depth.

9p21 deletions in primary melanoma.

Formalin-fixed, paraffin-embedded primary melanoma biopsies were evaluated for evidence of genomic loss on the short arm of chromosome 9 using microsatellite PCR assays for the D9S157, D9S161 and D9S171 loci. Paired normal and tumor DNA was extracted from the same block for comparison of microsatellite marker patterns. Some detectable abnormality was seen in at least one of these loci in 15 of 44 evaluable specimens (34%). Homozygous deletions were detectable at these loci in 8 of 44 informative specimens (18%) and hemizygous deletions were seen in 11 of 44 informative specimens (25%). Deletions at 9p were more likely to be found as primary tumor thickness increased (p < 0.05). This evidence supports the concept that 9p21 deletions are involved in primary sporadic melanomas, and that 9p deletions are not solely an in vitro phenomenon.

Pigmented lesions in actinically damaged skin. Histopathologic comparison of biopsy and excisional specimens.

BACKGROUND AND DESIGN: A consecutive sample of 46 cases was collected for comparative histologic evaluation. Results of incisional biopsies of cutaneous pigmented lesions interpreted as lentigo maligna, melanoma in situ, or invasive melanoma, and those suggestive, but not diagnostic, of melanoma were collected. Those lesions that were on actinically damaged skin and in which biopsy was followed by complete excision within 6 months were included. Incisional biopsies that removed greater than 50% of the surface area of the lesion were excluded. RESULTS: Of the excisional specimens, 40% demonstrated histopathologic features more pronounced than those in the biopsy specimens. Areas of invasive melanoma not detected in the biopsy specimens were observed in 20% of the excisional specimens. Accurate diagnosis based on small biopsy specimens was not always possible because of the absence of a classic lentigo maligna histologic pattern in many cases. The most frequent deviation from the pattern was the presence of lentiginous epidermal hyperplasia within these lesions. CONCLUSIONS: These results suggest that limited sampling may be inadequate for an accurate diagnosis of pigmented melanocytic lesions on actinically damaged skin. Areas chosen for biopsy may not contain the most advanced areas histologically and may fail to detect foci of invasive melanoma elsewhere within the lesion.

Unilateral adrenal enlargement due to Histoplasma capsulatum.

Human infection with Histoplasma capsulatum runs the gamut from asymptomatic to disseminated disease. CT-directed fine-needle aspiration of bilaterally enlarged adrenal glands has been used in diagnosing serious infections with this ubiquitous organism. Three cases have previously been reported in which H. capsulatum infection caused unilateral adrenal enlargement; this enlargement was diagnosed post-mortem. We describe three patients with unilateral adrenal enlargement due to H. capsulatum whose conditions were diagnosed antemortem. We encourage clinicians to include infection with H. capsulatum as well as other granulomatous diseases and tumors in the differential diagnosis of unilateral adrenal enlargement.

Role of the tricuspid annulus and the eustachian valve/ridge on atrial flutter. Relevance to catheter ablation of the septal isthmus and a new technique for rapid identification of ablation success.

BACKGROUND: Typical atrial flutter (AFL) results from right atrial reentry by propagation through an isthmus between the inferior vena cava (IVC) and tricuspid annulus (TA). We postulated that the eustachian valve and ridge (EVR) forms a line of conduction block between the IVC and coronary sinus (CS) ostium and forms a second isthmus (septal isthmus) between the TA and CS ostium. METHODS AND RESULTS: Endocardial mapping in 30 patients with AFL demonstrated atrial activation around the TA in the counter-clockwise direction (left anterior oblique projection). Double atrial potentials were recorded along the EVR in all patients during AFL. Pacing either side of the EVR during sinus rhythm also produced double potentials, which indicated fixed anatomic block across EVR. Entrainment pacing at the septal isthmus and multiple sites around the TA produced a delta return interval < or = 8 ms in 14 of 15 patients tested. Catheter ablation eliminated AFL in all patients by ablation of the septal isthmus in 26 patients and the posterior isthmus in 4. AFL recurred in 2 of 12 patients (mean follow-up, 33.9 +/- 16.3 months) in whom ablation success was defined by the inability to reinduce AFL, compared with none of 18 patients (mean follow-up, 10.3 +/- 8.3 months) in whom success required formation of a complete line of conduction block between the TA and the EVR, identified by CS pacing that produced atrial activation around the TA only in the counterclockwise direction and by pacing the posterior TA with only clockwise atrial activation. CONCLUSIONS: (1) The EVR forms a line of fixed conduction block between the IVC and the CS; (2) the EVR and the TA provide boundaries for the AFL reentrant circuit; and (3) verification of a complete line of block between the TA and the EVR is a more reliable criterion for long-term ablation success.

Small-diameter invasive melanomas: clinical and pathologic characteristics.

BACKGROUND: Most melanomas when first diagnosed clinically are larger than common benign melanocytic nevi ( > 6 mm). Smaller melanomas, however, may occasionally occur. Yet, very little is known about them. OBJECTIVE: To determine the incidence and delineate the clinical and histologic characteristics of small-diameter invasive melanomas. METHODS: Slides of all melanomas diagnosed between 1984-1993 were reviewed and measured. All invasive lesions less than 6 mm were further scrutinized clinically and morphologically. RESULTS: Among 357 invasive melanomas, 16 (4.4%) were less than 6 mm. Most lesions lacked some of the histologic features usually seen in large melanomas. One half of them were over 0.75 mm deep. Patients with small melanomas were on average 15 years younger than those with large lesions. In females, sites on the upper extremities predominate. In females, small melanomas had clinical signs of melanoma, while in males they resembled nevi. CONCLUSION: Melanomas smaller than 6 mm are not rare. Clinicians and pathologists must learn their features in order to diagnose them properly.

Comparison of in vivo tissue temperature profile and lesion geometry for radiofrequency ablation with a saline-irrigated electrode versus temperature control in a canine thigh muscle preparation.

BACKGROUND: It is thought that only a thin layer of tissue adjacent to the electrode is heated directly by electrical current (resistive heating) during radiofrequency ablation. Most of the thermal injury is thought to result from conduction of heat from the surface layer. The purpose of this study was to determine whether lesion depth could be increased by producing direct resistive heating deeper in the tissue with higher radiofrequency power, allowed by cooling the ablation electrode with saline irrigation to prevent the rise in impedance that occurs when the electrode-tissue interface temperature reaches 100 degrees C. METHODS AND RESULTS: In 11 anesthetized dogs, the thigh muscle was exposed and bathed with heparinized canine blood (36 degrees C to 37 degrees C). A 7F catheter, with a central lumen, a 5-mm tip electrode with six irrigation holes, and an internal thermistor, was positioned perpendicular to the thigh muscle and held at a constant contact weight of 10 g. Radiofrequency current was delivered to 145 sites (1) at high constant voltage (66 V) without irrigation (CV group, n = 31), (2) at variable voltage (20 to 66 V) to maintain tip-electrode temperature at 80 degrees C to 90 degrees C without irrigation (temperature-control group, n = 39), and (3) at high CV (66 V) with saline irrigation through the catheter lumen and ablation electrode at 20 mL/min (CV irrigation group, n = 75). Radiofrequency current was applied for 60 seconds but was terminated immediately in the event of an impedance rise > or = 10 omega. Tip-electrode temperature and tissue temperature at depths of 3.5 and 7.0 mm were measured in all three groups (n = 145). In 33 CV irrigation group applications, temperature was also measured with a separate probe at the center (n = 18) or edge (n = 15) of the electrode-tissue interface. In all 31 CV group applications, radiofrequency energy delivery was terminated prematurely (at 11.6 +/- 4.8 seconds) owing to an impedance rise associated with an electrode temperature of 98.8 +/- 2.1 degrees C. All 39 temperature-control applications were delivered for 60 seconds without an impedance rise, but voltage had to be reduced to 38.4 +/- 6.1 V to avoid temperatures > 90 degrees C (mean tip-electrode temperature, 84.5 +/- 1.4 degrees C). In CV irrigation applications, the tip-electrode temperature was not > 48 degrees C (mean, 38.4 +/- 5.1 degrees C) and the electrode-tissue interface temperature was not > 80 degrees C (mean, 69.4 +/- 5.7 degrees C). An abrupt impedance rise with an audible pop and without coagulum occurred in 6 of 75 CV irrigation group applications at 30 to 51 seconds, probably owing to release of steam from below the surface. In the CV and temperature-control group applications, the temperatures at depths of 3.5 (62.1 +/- 15.1 degrees C and 67.9 +/- 7.5 degrees C) and 7.0 mm (40.3 +/- 5.3 degrees C and 48.3 +/- 4.8 degrees C) were always lower than the electrode temperature. Conversely, in CV irrigation group applications, electrode and electrode-tissue interface temperatures were consistently exceeded by the tissue temperature at depths of 3.5 mm (94.7 +/- 9.1 degrees C) and occasionally 7.0 mm (65.1 +/- 9.7 degrees C). Lesion dimensions were smallest in CV group applications (depth, 4.7 +/- 0.6 mm; maximal diameter, 9.8 +/- 0.8 mm; volume, 135 +/- 33 mm3), intermediate in temperature-control group applications (depth, 6.1 +/- 0.5 mm; maximal diameter, 11.3 +/- 0.9 mm; volume, 275 +/- 55 mm3), and largest in CV irrigation group applications (depth, 9.9 +/- 1.1 mm; maximal diameter, 14.3 +/- 1.5 mm; volume, 700 +/- 217 mm3; P < .01, respectively). CONCLUSIONS: Saline irrigation maintains a low electrode-tissue interface temperature during radiofrequency application at high power, which prevents an impedance rise and produces deeper and larger lesions. A higher temperature in the tissue (3.5 mm deep) than at the electrode-tissue interface indicates that direct resistive heating occurred deeper

Rochalimaea henselae infection in acquired immunodeficiency syndrome causing inflammatory disease without angiomatosis or peliosis. Demonstration by immunocytochemistry and corroboration by DNA amplification.

Rochalimaea henselae causes bacillary angiomatosis, bacillary peliosis, and persistent bacteremia. Difficult to cultivate, it is detectable in infected tissues by immunocytochemistry. This technique demonstrated R henselae in autopsy specimens obtained from three deceased patients who had acquired immunodeficiency syndrome, with pathologic tissue changes lacking neoangiogenic features. From the first patient, the cause of nodular collections of lymphocytes and nonepithelioid histiocytes in the liver, spleen, lymph nodes, bone marrow, and heart eluded detection until immunocytochemical identification of R henselae. In the second case, unexpected gross and microscopic necroinflammatory nodules in the liver and spleen contained Warthin-Starry-staining bacilli identified as R henselae immunocytochemically. The third patient was found to have pathologic changes in his liver and spleen comparable with those of the second case, as well as several other disseminated infections. In two cases, identification of R henselae was corroborated through sequencing polymerase chain reaction-amplified bacterial DNA recovered from tissue; in one case, DNA could not be amplified, possibly because of postmortem degradation. Application of the immunocytochemical technique thus has expanded the recognized spectrum of histopathologic findings associated with R henselae infection in acquired immunodeficiency syndrome, as well as proving to be potentially more sensitive than DNA amplification for this purpose when applied to autopsy tissues.

Spontaneous haematomyelia: a necropsy study.

Spontaneous haematomyelia (intramedullary spinal haematoma), is an uncommon event. Predisposing conditions have been reported including syringomyelia, pregnancy and delivery, angioma, spinal artery aneurysm, and haemophilia, but only rarely has a pathological evaluation been performed. Two such cases studied at necropsy are reported. In one case, the haematoma was restricted to the cervical spinal cord, while in the second case it extended from the medulla into the lowest thoracic cord segments. In both cases the haematomyelia was fatal. In the first case the clinical course was subacute, but in the other the course was more acute. Careful neuropathological examination showed no apparent cause for the haemorrhages.

Effects of CO2 laser beam on cortical bone.

Sixteen bone blocks from two freshly amputated legs were used to study the effect of CO2 laser on cortical bone. They were divided into two groups. In Group I, the blocks were treated with CO2 laser using 1 mm spot (focused mode). In Group II, they were treated with CO2 laser using 3 mm spot (defocused mode). Two other variables were investigated: the power and time of exposure. Three histologic zones were observed: a superficial zone with black particle deposits (carbonization), an intermediate zone with fibrillations and enlarged empty lacunae, and a deep zone with normal appearing bone. The bony changes in the first two zones combined were superficial in all specimens and did not exceed 200 microns. Increased energy, a focused beam, and time of exposure were all associated with increased matrix changes. CO2 laser can be applied to cortical bone in vitro with minimal residual thermal damage.

Delayed reaction to "lead" pencil simulating melanoma.

A 74-year-old man had sustained a penetrating lead pencil injury to his right lower leg at the age of fifteen. A dark gray macule occurred that remained unchanged for fifty-eight years. An enlarging black nodule appeared in this area, simulating a melanoma, when the patient was seventy-three years old. Histologic examination revealed exogenous pigment and a foreign body reaction.

Vaterian cancer in siblings.

The simultaneous occurrence of Vaterian carcinoma in two siblings suggests a genetic influence in their pathogenesis. Their classic clinical presentation of obstructive jaundice and weight loss required pancreaticoduodenectomy for this neoplasm. Pedigree analysis revealed a third sibling who died from an unresectable periampullary malignancy. Neither of the probands exhibited, as late as the seventh decade, evidence compatible with a diagnosis of familial polyposis coli or Gardner's syndrome. Flow cytometry studies revealed an aneuploid distribution in one tumor and tetraploid in the other. The rarity of this neoplasm, in the absence of contributing epidemiologic factors, suggests that this is a pleotrophic manifestation of a cancer-prone genotype.

Histologic and electrophysiologic changes following subepineurial hematoma induction in rat sciatic nerve.

The sciatic nerves of 34 rats were used to study the effects of intraneural, extrafascicular hematoma, exclusive of any other trauma. Electrodiagnostic, histologic, and electron microscopic techniques were used. The amount of nerve fiber damage was assessed using computerized planimetry. The effects of hematoma evacuation were also investigated. Changes consistent with partial denervation, such as prolongation of insertion activity and distal latency, and the presence of positive waves and fibrillations, were present in the blood-injected but not in the control groups. Degenerative nerve fiber changes localized to the area of hematoma were present in the blood-injected group and were significantly higher than those in the control group. Although there was a difference in the amount of nerve damage between the blood-injected and the hematoma-evacuated group (less damage), this difference was not statistically significant. These findings suggest that intraneural extrafascicular hematoma produces electrophysiologic and histologic evidence of axonal degeneration affecting nerve fibers in the vicinity of the hematoma. Early evacuation of the intraneural hematoma appears to slightly reduce the deleterious effects of the lesion.

Occupational hydrocarbon exposure and renal histopathology.

A blinded, retrospective study of histological sections from ten hydrocarbon-exposed and twenty unexposed nephrectomized renal cell carcinoma cases was conducted to evaluate the histopathologic features present in the apparently normal kidney parenchyma removed with the tumor. Tissue sections from each of the thirty cases were independently reviewed by three consulting pathologists and scored using well defined criteria. Occupational hydrocarbon exposure indices were developed by a team of industrial hygienists and applied to the detailed occupational history of each exposed case. A positive correlation was observed between age and the total renal pathology score (rs = .40, p less than .03). No correlation was found between indices of occupational hydrocarbon exposure and renal pathology scores among exposed cases. No significant differences in renal pathology scores were noted when exposed cases were matched to unexposed cases by age, sex, and race. These results are limited by the inclusion of only cases with historical hydrocarbon exposures. It is recommended that a follow-up study be conducted, utilizing sensitive quantitative methods, to define what, if any, cytopathologic renal effects occur in conjunction with current occupational exposures to hydrocarbons.