Alteration of Renal Blood Flow during Sequential Embolization of the Canine Kidney

Experimental embolization of the renal artery with cross-linked dextran (CLD) microspheres was performed in 6 dogs. The blood flow was monitored by electromagnetic flow meter (EM) in 3 dogs and by video dilution technique (VDT), adapted to an angiographic digital subtraction system, in a second group of 3 dogs. Retrograde flow in the embolized renal artery was detected by 99Tcm microspheres. Sequential emboli produce a predictable and equal flow response with both measuring techniques. Thus, the less invasive VDT can be used in the clinical setting to optimize and control embolization procedures. This type of flow monitoring has great potential in alerting the angiographer when approaching the risk level for retrograde flow.

Effect of insulin-like growth factor type I on critical size calvarial bone defects in irradiated rats

Irradiated wounds are characterized by a slow healing process. Insulin-like growth factor-1 (IGF-1), a somatomedin C, has been shown in previous studies to stimulate collagen synthesis and bony repair. The purpose of this investigation is to evaluate the potential beneficial effects of recombinant IGF-1 in the healing of critical size calvarial defects in previously irradiated adult male Sprague-Dawley rats.

Hepatic ablation using bipolar radiofrequency electrocautery

RATIONALE AND OBJECTIVES

Percutaneous methods have been used to treat primary and secondary hepatic neoplasms. In the current study, we evaluated the potential of bipolar radiofrequency (RF) electrocautery to increase in vitro liver tissue destruction when compared with monopolar RF electrocautery.

METHODS

Two needles (electrodes) were placed into fresh bovine liver tissue for use with bipolar electrocautery. Needle tip exposure was kept constant at 3 cm while other parameters, including treatment time, power (wattage), interneedle distance, and needle tip temperature, were changed. Pathologic and histologic correlation was performed, and tissue necrosis was weighed in grams for individual parameters.

RESULTS

There was a minimal threshold of approximately 45 degrees C where tissue coagulation occurred. Tissue coagulation increased the longer treatment went on. Increasing temperature, wattage, or both increased tissue coagulation such that necrosis was too rapid and char formation occurred, which prevented further coagulation. For all wattages and temperatures, there was increasing tissue necrosis with increasing needle separation, until a point at which further needle separation produced less tissue necrosis. Optimizing parameters allowed tissue coagulation of greater than 30 g.

CONCLUSION

Bipolar RF electrocautery shows promise for increasing the tissue coagulation in fresh bovine liver compared with the previously described monopolar technique.

Cranial bone grafting: biodegradable versus titanium fixation in a rabbit model

Rigid internal fixation with miniplates and screws has enabled reconstructive surgeons to position bony segments precisely. Unfortunately, our present systems have been associated with a potential adverse effect on ultimate craniofacial growth and development. Also, they may be palpable, necessitating secondary procedures for removal of the hardware. We have been involved in an ongoing study evaluating the efficacy of a commercially developed biodegradable system. In this study, we compared biodegradable lag screw fixation with traditional titanium screw fixation in full-thickness, membranous bone grafts harvested from the zygomatic arches to the snout in a rabbit model. The results were compared with standard hematoxylin and eosin stains and laser densometry. Although this study adds further credence to the resorption of bone grafts, those secured with the polyglycolic acid screws demonstrated significantly less resorption than those maintained in position by traditional methods.

Polyglyconate fixation successfully stabilizes zygomatic osteotomies in a nonhuman primate

Investigators have reported problems with metal plates and screws, including restriction of craniofacial growth necessitating secondary removal; bone resorption secondary to stress shielding; increased incidence of infection, extrusion, and palpability, especially in regions with minimal soft-tissue coverage; and interference with radiological studies and postoperative radiation therapy. Biodegradable rigid fixation can easily eliminate a majority of these problems because the material provides adequate fixation for a finite interval corresponding to bony repair. For this reason, there has been increasing interest in developing satisfactory biodegradable plate and screw systems. We tested a commercially developed polyglyconate plate and screw system to stabilize zygomatic osteotomies in a nonhuman primate model before embarking on clinical trials. In this experimental model, the stabilized segments revealed satisfactory alignment; in the control animals, the bony fragments became significantly displaced. This polyglyconate plate and screw system appears to have a promising role in the surgical correction of craniomaxillofacial deformities in humans, and clinical testing should commence.

Histogenesis of adenosquamous bronchogenic carcinoma

In our hamster lung cancer model studies, among 463 non-small-cell lung cancers (NSCLC), there were 47 adenosquamous neoplasms. In 24 of 27 lesions with diameters of less than 3.0 mm, the adenocarcinoma and the squamous cell carcinoma components arose as separate, spatially discrete lesions, but these were separate in only 7 of 20 lesions with diameters of 30 mm or greater. Co-infiltration of the components became more frequent as tumor size increased. The usual adenosquamous variety of NSCLC is likely a collision tumor, with each component possessing separate biological characteristics. Thus, future prognostically directed studies of this variety of NSCLC must recognize that these neoplasms have two components, each of which needs to assessed.

Successful xenotransplantation of human lung cancer correlates with the metastatic phenotype

BACKGROUND

Occult micrometastases could explain deaths from stage I non-small cell lung cancer (NSCLC) after complete resections. If patients who have occult metastases could be identified, systemic therapy might be beneficial.

METHODS

Non-small cell lung cancers from 81 patients in stages I, II, and III were transplanted to nude beige mice. Mean follow-up was 22.5 months (2 to 61 months).

RESULTS

Twenty-one xenotransplants successfully took, and seven metastasized in the nude mice. Neither the predominant cell type nor the incidence of lymph node metastases correlated with the results of xenotransplantation. Of the 21 patients whose NSCLCs took in xenotransplantation, 13 (61.9%) have had development of metastases, and 9 (42.9%) have died of the cancer. Among the 57 patients whose NSCLCs did not take, 14 (24.6%) have had development of metastases, and 9 (15.8%) have died of their cancer. The higher incidence of metastases in association with xenotransplant take is significant (p = 0.0032).

CONCLUSIONS

Patients whose NSCLCs take in xenotransplantation are at high risk for metastases. The xenotransplantation model is a step toward facilitating precise cellular biologic definition of the metastatic propensity of human NSCLC:

Biodegradable polyglyconate plates and screws: a histological evaluation in a rabbit model

Within the zygomatic arch, bilateral osteotomies were performed on 20 adult male New Zealand white rabbits. These were stabilized in an anatomical position with polyglyconate acid plates and screws. At 3, 4, 6, 9, and 12 months, rabbits were killed and their zygomatic complexes removed en bloc. Specimens were serially sectioned for standard histological examination. Although no gross reactions were noted throughout the course of this investigation, histological reactions were brisk. At 3 months, particulate material was surrounded by a foreign body giant cell-type reaction. The quantity of foreign material appeared to decrease by 4 months, at which time the foreign body reaction was partially replaced by fibrous tissue. By 6 months, there was a thick periosteal scar at the osteotomy site with a few islands of persistent foreign material. These were primarily seen in small, irregular vesicular spaces surrounded by a large number of histiocytes with their characteristic foamy-cytoplasm. Although this foreign body reaction had subsided by 12 months, small foci of chronic inflammation still persisted.

Effect of insulin-like growth factor type 1 on critical-size defects in diabetic rats

A number of investigators have reported on the clinically significant relationship between diabetes mellitus and impaired wound healing. Diabetic patients have an increased frequency of infection, delayed scar formation, and poor bony union. Investigations completed in our laboratory have demonstrated that insulin-like growth factor type 1 (IGF-1), a somatomedin C, has shown promise for accelerating bony repair. The purpose of this study was to examine the effects of recombinant IGF-1 on standardized, critical-size calvarial defects in 25 adult, male streptozocin-induced diabetic rats. From our study, it appears that IGF-1 exerts a potentiating effect on the repair of bony defects in diabetes-induced rats.

Repair of experimental calvarial defects with Bio-Oss particles and collagen sponges in a rabbit model

Various materials have been used for reconstruction of both acquired and congenital calvarial defects. Unfortunately, each has its limitations. Autologous bone grafts have irregular rates of resorption that may require secondary corrective surgery, and individual harvest sites have limited stores that can necessitate additional donor locations. Alloplastic materials have unlimited quantities and volume stability but they may not become incorporated and are associated with a higher incidence of infection. The optimal bone substitute should stimulate new bone formation and permanently supplant the temporary space filler, thereby reconstituting the surgical defect. We evaluated 2 newly available bone substitutes, resorbable natural bone mineral (Bio-Oss particles) and a combination of collagen and natural bone mineral collagen combination (Bio-Oss sponges), to repair calvarial defects in an adult, male, New Zealand white rabbit model. We found that the particulate Bio-Oss material resorbed and then underwent the normal physiological stages of bone remodeling. The collagen and Bio-Oss combination was replaced by new bone ingrowth. These materials may have potential for use in the reconstruction of skull defects.

Retrograde ejaculation due to heterotopic erectile tissue

We report a case of retrograde ejaculation due to an unusual prostatic urethral mass. The resected tissue was histologically indistinguishable from corpus spongiosum, and due to its location it was diagnosed as heterotopic erectile tissue. The embryological origin of this lesion is discussed.

Effect of insulin-like growth factor-1 on zygomatic arch bone regeneration: a preliminary histological and histometric study

A number of physicians have attempted to pharmacologically manipulate the healing of bony fractures with a variety of agents such as growth hormone, thyroxine, chondroitin sulfate, and parathyroid hormone. Thus far, results from these experiments have been inconclusive. Previous research dealing with insulin-like growth factors has centered on cultures of osteoblast-like cells and has demonstrated a stimulatory effect on bone collagen synthesis, which may in fact play a critical role in the process of bone formation itself. The purpose of this investigation was to examine the effects of a genetically engineered growth factor, insulin growth factor type I, on midfacial fracture healing. In 24 adult male Sprague-Dawley rats, a standardized defect was created within the midportion of each zygomatic arch. One-half were treated with insulin growth factor type I administered with an osmotic infusion pump and the other half served as control subjects. At 2, 4, 8, and 12 weeks, animals from each group were killed and specimens of the defect obtained. Data were collected from radiographs and histological studies to compare the extent of bony repair. From this study, it appears that insulin growth factor type I could exert a potentiating effect on the repair of midfacial bone defects.

The effects of insulin-like growth factor-1 on critical-size calvarial defects in Sprague-Dawley rats

In a previous study prepared in 1992, we found that insulin-like growth factor-1 showed promise in hastening intramembranous bone repair in midfacial bone defects. For the present study, we created critical-size calvarial defects in 36 adult male Sprague-Dawley rats. The rats were then divided into two groups and killed at 1, 2, 3, 4, 5, 6, and 8 weeks. Twenty-one rats were administered insulin-like growth factor-1 subcutaneously with a 14-day osmotic infusion pump. An untreated group served as controls. Results were compared using routine histology to examine bone reconstitution of the surgical defects. Within the experimental group, we observed repair commenced at approximately 1 week and the critical-size calvarial bone defects were completely obliterated by 6 weeks; in the control group, even by 8 weeks, the surgical defects remained almost unchanged. In summary, this is further evidence that insulin-like growth factor-1 may have the potential to accelerate repair of intramembranous bone defects.

Polyglyconate plates and screws to stabilize zygomatic osteotomies in a rabbit model

Rigid internal fixation with miniplates and screws continues to be widely used in the correction of both congenital and acquired craniomaxillofacial deformities. This technique allows precise three-dimensional stabilization of bony segments. A number of recent reports have detailed some disadvantages, including potential growth restriction in developing children, bone resorption, infection, extrusion, and palpability. These problems have often necessitated secondary surgery for hardware removal. A biodegradable plate and screw system would eliminate these potential and real problems. Over the last 2 decades, there has been an escalating interest in developing satisfactory biodegradable materials for bony fixation. We have previously reported the initial phases of a long-term evaluation of various biomaterials currently available. The purpose of this study is to examine a biodegradable plate and screw system fabricated from a faster resorbing material--polyglyconate. This system would be applicable to pediatric reconstructive problems. Earlier studies have shown its tissue compatibility and feasibility for multiple surgical uses. Osteotomies were created at the midpoint of each zygomatic arch of 42 adult male white New Zealand rabbits. The animals were then divided into two equal groups. The first group served as a control and the bony segments were permitted to heal without stabilization, whereas in the experimental group, the bony segments were stabilized with biodegradable plates and screws made from polyglyconate. Animals were then sacrificed at 2, 4, 6, 8, 12, and 16 weeks, at which time radiographs were obtained. Zygomatic complexes were then removed en bloc, and routine hematoxylin and eosin slides were made for light microscopy. Without fixation, fracture segments became significantly displaced.(ABSTRACT TRUNCATED AT 250 WORDS)

Midfacial fracture repair in the adult rat

The consensus in the literature is that fracture healing within the midface occurs via fibrous union. Clinical experience with the surgical correction of established traumatic deformities has not borne this out. An earlier histological examination with human biopsy specimens demonstrated that eventually repair occurred by direct bony union. However, a recent study in a rabbit model challenged this conclusion and indicated that the process of new formation resembles secondary bone formation as in endochondral formed bone. The purpose of our inquiry is to elucidate further the process of midfacial bony repair in an adult male Sprague-Dawley rat model.

Reconstruction of calvarial defects with anorganic bovine bone mineral (Bio-Oss) in a rabbit model

Reconstructive surgeons have employed various procedures using either autogenous or alloplastic materials to repair cranial defects secondary to trauma, extirpative surgery, or congenital anomalies. Currently, the choice appears to be dependent on the personal choice or background of the operating surgeon. For years, our preference has been to use calvarial bone grafts as our primary source of reconstructive material. Disadvantages include uneven resorption of the bone grafts and limited quantities. For these reasons, bony substitutes present new possibilities for reconstruction of craniomaxillofacial defects. We evaluated Bio-Oss, which is a natural bone mineral derived from a bovine source that is chemically and physically identical to human bone, as a possible replacement material to reconstruct skull defects in a rabbit model.

The effect of insulin growth factor-1 on calvarial sutures in a Sprague-Dawley rat

Early investigations attempting to determine the exact pathogenesis of premature closure of the cranial sutures were limited by the untoward sequelae caused by surgical procedures in animal models to simulate the development of craniosynostosis. In an attempt to create a model for evaluating the effects of manipulating the craniofacial sutures without the limitations of associated scarring, we conceived an animal prototype dependent on the effects of insulin growth factor-1 on the anterior frontal suture in a Sprague-Dawley rat model. The experimental group received 2 mg of IGF-1 over a 14-day period via a subcutaneously placed osmotic infusion pump, whereas the age-matched control group received no treatment. We present our preliminary histological results describing the effect of IGF-1 on calvarial sutures.

Hepatic ablation with use of radio-frequency electrocautery in the animal model

The potential of percutaneous radio-frequency (RF) electrocautery hepatic ablation was evaluated in the animal model. RF hepatic ablation was performed under ultrasound (US) guidance in the liver of 10 swine with use of a specifically designed needle. The needle was placed through the liver capsule, and ablation was performed after isolating the liver at laparotomy. Animals were killed immediately (n = 4), at 1 week (n = 1), 2 weeks (n = 3), or at 5 weeks (n = 2). The US findings were correlated with the pathologic results in the animal livers. RF hepatic ablation was successfully performed in the animal model without complications. Lesions in the animal livers were typically 1 x 2 cm, which initially appeared highly echogenic on US scans. These images corresponded to an area of hepatic necrosis. The lesions became less echogenic shortly after initial treatment but could still be visualized with US at 5 weeks. At histologic study at 5 weeks, the treated livers showed central debris, a larger area of necrotic liver, and a zone of granulation tissue surrounded by a fibrotic capsule. No complications were encountered. RF hepatic ablation shows future promise in treatment of hepatic neoplasms.

Use of biodegradable plates and screws in a rabbit model

During the last decade, rigid internal fixation with miniplates and screws has gained widespread acceptance in the correction of both congenital and acquired craniomaxillofacial deformities. Recent studies have proposed that the currently employed metallic plates and screws may require removal because of potential facial growth restriction in growing children. Others have reported bone resorption under the plate due to stress shielding, infection, extrusion, and palpability in regions where there is minimal tissue coverage. Because these implants are radiopaque, they generate significant that interfere with radiological studies and with radiation therapy in patients undergoing treatment for malignancies. There is no question that the use of a biodegradable plating system would eliminate each of these potential or real problems, because stability is necessary only for a reasonably short period until the fracture segments have become united. We report the initial phase of a long-term study examining various materials that will be available for fabrication of a biodegradable plate and screw system. We evaluated a commercially developed biodegradable plate and screw system to treat zygomatic arch fractures in a rabbit model. Fractures were surgically created at the midpoint of each zygomatic arch. The experimental animals were then divided into three equal groups. Fractures in the first group were permitted to heal without any form of stabilization. In the second group, segments were secured with standard titanium plates and screws. Biodegradable plates and screws were employed for stabilization in the experimental group. Animals were then killed, and radiographs were obtained at 2, 4, 6, and 8 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental renal embolization: preliminary results with polyacrylonitrile-based multiblock copolymers

Preparations of polyacrylonitrile (PAN) are now being considered as possible new therapeutic embolization agents. This study evaluated two different liquid PAN formulations and a solid particle form (particle diameters, 100-400 microns). Eighteen rabbits underwent unilateral renal embolization with one of the three different preparations (n = 6 in each group). PAN was effective in causing infarcts in all embolized kidneys, which were documented with both angiograms and pathologic findings. These preliminary results show that PAN may have promise as an effective agent for clinical renal embolizations.

Two phase radiofrequency catheter ablation of isolated ventricular endomyocardium

This report describes a two phase radiofrequency (TPRF) energy source producing two radiofrequency sinusoidal voltages of similar frequency but different phase angles between three points of wire. When delivered through an orthogonal electrode catheter array (OECA) TPRF energy produces a square-shaped lesion of the area covered by the five electrodes (0.8 cm2). The purposes of the study were: to create square-shaped lesions using TPRF energy; to compare the size of lesions created by single phase radiofrequency (SPRF) to that of TPRF energy; and to study the depth of such lesions and to create lesions of desired size by adjacent placement of the OECA using TPRF energy. Ablations were created in nine isolated bovine hearts using three power settings (10, 20, and 40 watts) and three pulse durations (5, 10, and 20 seconds). Pathological examination was performed to document the length, width, depth, and the microscopic changes of ablations. TPRF energy increases the size of lesion (P less than 0.001) and utilizes less power (P less than 0.008) at the same power setting and pulse duration compared to SPRF energy. This is possibly related to earlier rise in impedance with TPRF compared to SPRF ablations. The largest lesion for both SPRF (0.51 +/- 0.08 cm2) and TPRF (1.03 +/- 0.18 cm2) ablations were observed at 20 watts for 20 seconds. By adjacent placement of the OECA and TPRF energy desired size (6 cm2) lesions were created. There was no significant difference between the depth of SPRF versus TPRF ablations at comparable power setting and pulse duration. Pathological examination revealed the shape of lesions were elliptical or cross-shaped for SPRF and square for TPRF ablations. Microscopic examination revealed coagulation necrosis, edema, and few necrotic cardiac muscle strands.

CONCLUSIONS

TPRF energy can cause 1.2 cm2 lesions. TPRF compared to SPRF energy causes larger lesions but depth of lesions are not different than SPRF energy at the same power setting and pulse duration. By adjacent placement of OECA and TPRF energy desired size lesion can be created (6 cm2).

Can histological assessment predict the outcome in interstitial cystitis?

In a retrospective study we compared the outcome of 39 patients with interstitial cystitis to the histological findings at initial diagnostic bladder biopsy. The degree of inflammation and fibrosis and the mast cell counts were assessed on each biopsy. The prognostic relevance of the clinical features of age, duration of symptoms, frequency, nocturia, pain and bladder capacity was assessed. The study showed no statistical correlation between the severity of histological findings at diagnosis and the eventual outcome of the disease. Over 50% of patients with severe histological abnormalities responded to conservative treatment. Although the majority of patients with mild pathological changes responded to conservative treatment, some did require surgical intervention. The clinical features of pain, nocturia and bladder capacity showed significant differences between the 2 patient groups. However, the former 2 features are subject to many variables and the latter probably has too wide a range to be useful as a prognostic indicator. Only the response of patients to conservative treatment will indicate those who are not being helped and who may eventually require surgical treatment.

The split calvarial bone graft donor site: the effects of surgicel and hydroxyapatite impregnated with collagen

Surgicel, which is commonly used as a hemostatic agent in clinical practice, is basically composed of oxidized regenerated cellulose. Skoog followed by Thilander and Stenstrom are credited with initially describing the use of Surgicel as a subperiosteal implant that could stimulate new bone formation in the closure of secondary palatal fistulae. Encouraged by these previous studies, we decided to investigate the effect of Surgicel and a new implant material, hydroxyapatite impregnated with collagen, on the split calvarial bone graft donor site. To do this, we used adult New Zealand White rabbits as our experimental model. Our study demonstrated histological evidence of both an increased quantity and earlier bony reformation, eventually reconstituting the surgical defect in the split calvarial bone graft donor site treated with Surgicel. Additionally, we found that this alloplastic implant material has potential in the reconstruction of the donor defect in selected patients.

Recurrent interstitial cystitis following cystoplasty: fact or fiction?

The severity of symptoms in interstitial cystitis may necessitate surgical treatment in approximately 10% of the patients. Substitution cystoplasty provides satisfactory results in most of these cases, while avoiding the need for urinary diversion. It has been suggested that interstitial cystitis may affect the bowel segment used in this form of operation. We studied bowel segments removed from cystoplasties in 5 patients with interstitial cystitis and compared these to bowel used for lower urinary reconstruction for other disorders in 6 patients. All segments showed varying degrees of inflammation, fibrosis and mastocytosis but there was no difference between the 2 groups for these features. We conclude that inflammation and fibrosis is the usual reaction of bowel to exposure to urine, and they do not represent a specific spread of interstitial cystitis in those patients. However, this reaction does mimic the histological appearance of interstitial cystitis in the bladder and may suggest a model for this disease.

Comparison of flow cytometry to routine testicular biopsy in male infertility

We compared DNA flow cytometry to morphologic evaluation of routine testicular biopsies as methods of monitoring spermatogenesis. The study group consisted of 14 azoospermic men and 5 others who underwent testicular surgery unassociated with fertility problems. The findings for both studies were divided into three groups: normal, moderately abnormal, and markedly abnormal. Correlations between the findings from routine biopsy and flow cytometry were good. Of 9 patients having normal testicular morphology, 7 had normal ploidy classes by DNA flow cytometry while 2 had moderately abnormal histograms. Of 5 cases with moderately abnormal morphology, 1 had normal, 1 had moderately abnormal, and 3 had markedly abnormal ploidy distributions. In 5 cases described as Sertoli cell only, all DNA histograms were markedly abnormal, consisting almost exclusively of diploid cells. DNA flow cytometry of testicular biopsies and aspirates has been demonstrated to be a rapid, reproducible, and objective approach in evaluating the infertile male and is a promising method to investigate spermatogenesis in an outpatient clinic in lieu of formal testis biopsy.

Quantitative DNA patterns in human preneoplastic breast lesions

In 12 cases of human mammary carcinoma in which a preneoplastic atypical ductal hyperplasia was also identified, quantitative DNA (QDNA) measurements of thionein-stained samples from both lesions were performed using the Cell Image Analysis 100 system. The QDNA values in the preneoplastic and neoplastic lesions from each case showed concordance (six as euploid and six as aneuploid/hyperdiploid). Such congruence suggests a stable inheritance of the somatic mutation(s) that is involved in carcinogenesis and that affects ploidy. If this relationship between concurrent preneoplasia and neoplasia in the ipsilateral breast is confirmed, it offers the possibilities of (1) identifying individuals at risk for developing neoplasias with defined biologic characteristics and (2) developing therapeutic regimens more appropriate to the risk assessment of each patient. It may be possible to conceive of a rational preventive regimen for cancer of the breast.

Papillomatous transformation of the gallbladder in metachromatic leukodystrophy

Papillomatous transformation of the gallbladder was found in a patient with metachromatic leukodystrophy who presented with an abdominal mass. Cholecystectomy was performed, and involvement of the gallbladder was confirmed by metachromatic stains and electron microscopy.

Alteration of renal blood flow during sequential embolization of the canine kidney

Experimental embolization of the renal artery with cross-linked dextran (CLD) microspheres was performed in 6 dogs. The blood flow was monitored by electromagnetic flow meter (EM) in 3 dogs and by video dilution technique (VDT), adapted to an angiographic digital subtraction system, in a second group of 3 dogs. Retrograde flow in the embolized renal artery was detected by 99Tcm microspheres. Sequential emboli produce a predictable and equal flow response with both measuring techniques. Thus, the less invasive VDT can be used in the clinical setting to optimize and control embolization procedures. This type of flow monitoring has great potential in alerting the angiographer when approaching the risk level for retrograde flow.

Dissolution of gallstones using methyl tertiary-butyl ether in an animal model

Human gallstones were surgically implanted in the gallbladders of six pigs. Through cholecystostomy catheters, methyl tertiary-butyl ether (MTBE) was infused from 3 to 5 days. MTBE successfully dissolved 19 of the 20 cholesterol stones and partially dissolved one mixed cholesterol-bilirubin stone. Gross and microscopic examination of abdominal organs revealed mild superficial ulcerations of the gallbladder and mild to moderate chronic inflammatory changes in the gallbladder of animals treated with MTBE infusion. There were no other significant changes within other abdominal organs except for mild inflammation of the duodenum in one animal and of the common bile duct in another. Because of its efficacy and limited deleterious effects, MTBE may be a good solvent when dissolving pure cholesterol gallstones in the gallbladder.

Dissolution of gallstones using cholecystostomy tube in the pig

Cholecystostomy catheters and human cholesterol gallstones were implanted surgically in the gallbladders of eight pigs. Through the catheters, mono-octanoin or sterile water (H2O) was infused from two to seven days. The mono-octanoin dissolved pure cholesterol gallstones smaller than 200 g. There was no stone dissolution with infusion of sterile water and only one stone larger than 250 g was dissolved with mono-octanoin. Side effects included moderate-to-severe inflammation and ulceration of the gallbladder with mono-octanoin instillation, which precludes its widespread use with the present treatment regimen. Infusion of water caused little gallbladder irritation.

Cystic dysplasia of testis

A rare developmental disorder, cystic dysplasia of the testis, encountered in a newborn infant, is described. The relationship to renal dysplasia and the recent literature are reviewed.

Glucagonoma--an underdiagnosed syndrome?

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Familial transitional cell carcinoma of renal pelvis and upper ureter

A family in which transitional cell carcinoma (TCC) of the renal pelvis and upper ureter developed in three siblings is presented. A description of these patients and their relatives together with a survey of the literature is presented.

Apocrine adenoma of the breast

Apocrine adenoma of the breast is a very rare entity. Criteria for diagnosis include qualification as adenoma and differentiation from apocrine carcinoma.

The role of the pathologist in the surgical treatment of hyperparathyroidism

Appropriately extensive surgical treatment of hyperparathyroidism depends upon accurate assessment of the extent of disease. We have believed that such assessement is the responsibility of the surgeon because at random biopsy with light microscopy the pathologist may not be able to differentiate adenoma from hyperplasia or even normal from abnormal glands. To test this hypothesis, three pathologists reviewed 50 unlabelled slides of parathyroid tissue and attempted to correlate them with clinical diagnoses which were based upon widely accepted criteria. They were asked to identify each slide as adenoma or hyperplasia, or both, or normal using whatever criteria they wished. A specific diagnosis of adenoma was correct in 35 and 83 per cent of interpretations and of hyperplasia in 38 and 60 per cent of interpretations. The less specific diagnosis of adenoma or hyperplasia (that is, abnormal tissue) was correct in 78 to 100 per cent. A diagnosis of normal was correct in 71 to 78 per cent. Adenoma was most likely confused with hyperplasia; hyperplasia was equally mistaken for adenoma or normal. We conclude that with random, subtotal specimens taken at biopsy (simulating intraoperative conditions) differentiation of adenoma from hyperplasia of the parathyroid gland is poor. Differentiation of normal from abnormal parathyroid tissue also is unreliable. Because the consequences of misdiagnosis are severe, pathologists should not be asked to make specific diagnoses intraoperatively but only to distinguish the parathyroid tissue from the nonparathyroid tissue.

Pulmonary oncocytoma

A pulmonary tumor composed of oncocytes was removed surgically from a 53-year-old man. Diagnosis was made after ultrastructural study. Pathological significance of this rare entity is briefly discussed and the literature reviewed.

Lymphoma arising in an adenolymphoma

A malignant lymphoma that originated in association with an adenolymphoma (Warthin's tumor) of the parotid salivary gland is reported. The occurrence of lymphomas in salivary glands is discussed briefly.

Dedifferentiated chondrosarcoma with a rhabdomyosarcomatous component

A case of dedifferentiated chondrosarcoma arising in the femur with metastasis to the lung is described. On immunoperoxidase studies and electron microscopic examination, both the anaplastic soft tissue extension of this tumor in the hip and the metastatic lung nodule showed evidence of rhabdomyosarcomatous differentiation. This case represents the first documented case of a chondrosarcoma with differentiation into a rhabdomyosarcomatous component.

Megacolon and neurofibromatosis: a neuronal intestinal dysplasia. Case report and review of the literature

This study presents the case of a patient with neurofibromatosis and megacolon. A diffuse, but patchy abnormality of neural tissue was present throughout the colon, especially in the myenteric plexus, but also in the submucosal plexus, smooth muscles, and lamina propria. This consisted of (a) a marked decrease in the number of argyrophilic neurons within the myenteric plexus, enlargement and deformity of those neurons present, and a marked increase of nerve fibers and nerve tract size in the myenteric plexus; (b) a proliferation of neurons and nerve fibers within the smooth muscle and submucosa; and (c) a proliferation of nerve fibers within focal areas of the lamina propria. The relationship of this case to previously reported cases of neuronal intestinal dysplasia and plexiform neurofibromatosis is discussed. Surgical treatment may be necessary and the surgical options are reviewed.