Oxidative stress potentiates BACE1 gene expression and Abeta generation.

Alzheimer's Disease (AD) is the most common neurodegenerative disorder leading to dementia and its prevalence increases with age. The pathological features of AD are characterized by the beta-amyloid protein (A(beta)) deposits in the core of neuritic plaques and abnormal neurofibrillary tangles in the brain of AD patients. BACE1 is the major beta-secretase to cleave the beta-amyloid precursor protein (APP) to generate A(beta). Oxidative stress has been shown to affect A(beta) generation in the AD pathogenesis and the mechanism of such effect is unknown. In this report we generated a novel promoterless enhanced green fluorescent protein (EGFP) reporter gene cloning vector and cloned a 1.9-kb BACE1 gene promoter fragment in this vector. The BACE1 promoter fragment can efficiently activate EGFP or luciferase gene transcription. Oxidative stress induced by hydrogen peroxide resulted in significant increase in the BACE1 promoter activity. Furthermore, hydrogen peroxide treatment facilitated beta-secretase activity and A(beta) generation. Thus, upregulation of BACE1 transcription by oxidative stress may contribute to the pathogenesis of Alzheimer's disease.

A prospective evaluation of the value of anorectal physiology in the management of fecal incontinence.

PURPOSE: This study was designed to determine whether anorectal physiology testing significantly altered patient management in the setting of fecal incontinence. METHODS: Patients referred to the anorectal physiology laboratory for evaluation of fecal incontinence were prospectively interviewed and examined by a colon and rectal surgeon. A decision to treat either medically or surgically was reached. The patients underwent physiologic testing with transanal ultrasound, pudendal nerve terminal motor latency, and anorectal manometry. A panel of board-certified colon and rectal surgeons then reviewed the history and physical examination, as well as the anorectal physiology tests, of each patient and reached a consensus on management. Management plans before and after physiologic evaluation were compared. RESULTS: Ninety patients (6 males) were entered into the study. The patients were divided in two groups: those with pretest medical management plans (n = 45) and those with pretest surgical management plans (n = 45). A change in management was noted in nine patients (10 percent). In the medical management group, the management changed from medical to surgical therapy in five patients. Transanal ultrasound detected anal sphincter defects in all patients who changed from medical to surgical management but in only 10 percent of those who remained under medical management (P = 0.0001). In the surgical management group, three patients (7 percent) changed from surgical to medical therapy and one patient (2 percent) changed from sphincteroplasty to neosphincter. Transanal ultrasound detected a limited anal sphincter defect in one patient (33 percent) who changed from surgical to medical management and a significant defect in all 41 patients (100 percent) who remained under surgical management (P = 0.003). CONCLUSIONS: Anorectal physiology testing is useful in the evaluation of patients with fecal incontinence. Without the information obtained from physiologic testing, 11 percent of patients who may have benefited from surgery would not have been given this option, and 7 percent of patients could have potentially undergone unnecessary surgery. Transanal ultrasound is the study most likely to change a patient's management plan.

Alcohol, head injury, and pulmonary complications.

The purpose of this study was to determine the difference in rates of pulmonary complications (e.g., aspiration, pneumonia) in head-injured patients with and without concomitant alcohol intoxication. The records of 98 consecutive patients admitted over a 1-year period to a Level I Trauma Center were reviewed. The patients were grouped into three subsets: acutely intoxicated (n = 26), acutely intoxicated with a diagnosis of chronic alcoholism (n = 14), and non-intoxicated (n = 58). Alcohol intoxication was defined as a blood alcohol level (BAL) > or = 0.08 mg/dl. Admission BALs and Glasgow Coma Scale (GCS) scores were tabulated at admission. Frequency of arterial blood gas (ABG) measurements, need for an artificial airway/mechanical ventilation, and length of stay (LOS) were analyzed by using one-way analysis of variance. Intergroup differences in breath sounds were compared by using the nonparametric Kruskall-Wallis technique. We found no statistical difference between groups in terms of pulmonary sequelae despite the remarkably high BALs observed in the study groups. Similarly, there was no statistically greater LOS in the groups with alcohol intoxication than in alcohol-free cohorts. Despite a great deal of BAL science research to support our hypothesis, we failed to demonstrate a significantly higher rate of pulmonary problems in inebriated individuals with head injuries. We found that our strict exclusion criteria (no concomitant chest, abdominal, or pelvic trauma) limited the sample to only those patients without significant intracranial bleeding, whereas most complications in blood alcohol neuroscience research have been associated with much larger mass lesions (e.g., epidural or subdural hematomas). In addition, we found the characterizations of patients as chronically alcoholic were cumbersome and inaccurate in many cases. Future research should allow for a greater range of concomitant injuries that might suggest a positive or negative relationship to acute intoxication.

Mouth to pouch transit after restorative proctocolectomy: hydrogen breath analysis correlates with scintigraphy.

OBJECTIVES: Fast intestinal transit may be responsible for slow adaptation and unacceptable steady-state function after restorative proctocolectomy. Investigation of GI transit time may be valuable in such a setting. We hypothesized that postprandial hydrogen breath tests may yield transit data that correlate with technetium-labeled meal scintigrams. METHODS: This study compared intestinal transit after a lactulose and bean meal via the breath hydrogen and scintigraphy methods in 21 ileoanal pouch subjects. The meal consisted of baked beans (425 g), 30 ml (20 g) lactulose syrup, 1 mCi 99mtechnetium sulfur colloid in finely chopped liver and 170 ml tap water. The meal contained 120 Kcal (70% carbohydrate, 18% protein and 12% fat). RESULTS: Of 21 pouch subjects, 11 (53%) had breath tests and scintigraphy transit studies that differed by 5-21 min. Three of 21 (14%) scintigraphy mouth to pouch transit times were faster than breath test transits by 43-107 min. Seven of 21 (33%) subjects did not have breath test peaks >10 ppm. Mouth to pouch transit for breath hydrogen (104+/-16 min) and scintigraphy (98+/-7 min) tests had significant correlation (r = 0.96, p < 0.0001) among subjects with alveolar hydrogen peaks and accurate scintigrams (n = 11). Scintigrams were five times more expensive than breath tests. CONCLUSIONS: A peaking hydrogen breath test provides an alternative to scintigraphy for estimating intestinal transit after ileoanal pouch.

Postnatal development of efferent synapses in the rat cochlea.

The development of olivocochlear efferent axons and their contacts in the postnatal cochlea was studied after DiI applications to the olivocochlear bundle in the ipsilateral brainstem of rats from 0 to 10 days of age (P0-10). Light microscopic analyses showed that labeled axons reached the vicinity of inner hair cells by P0 and outer hair cells by P2. Electron microscopic analyses demonstrated that labeled immature efferent axons are present among supporting cells of the greater epithelial ridge as well as inner hair cells at P0. The first efferent contacts that contacted inner hair cells contained a few irregularly sized vesicles and, occasionally, mitochondria. Postsynaptic specializations within inner hair cells apposed to labeled efferent axons included subsynaptic cisterns, irregularly sized vesicles, and synaptic bodies. Similar features were present in unlabeled profiles, presumed to be afferents, indicating that immature efferent axons could not be reliably distinguished from afferents without positive labeling. Efferent axons synapsed with outer hair cells by P4 and had synapse-like contacts at the bases of Deiters' cells at P4 and P6. Contacts between afferents and efferents were observed frequently in the inner spiral bundle from P6. As they matured, efferent axon terminals contacting hair cells contained increasing numbers of synaptic vesicles and were typically apposed by well-defined postsynaptic cisterns, thus acquiring distinctive profiles.

Clinical use of the self-expanding metallic stent in the management of colorectal cancer.

PURPOSE: This report describes our experience with the use of self-expanding metallic stents (SEMS) in the management of obstructing colorectal cancer. METHODS: A retrospective chart review of all patients undergoing placement of SEMS between May 1997 and January 2000 was performed. RESULTS: Insertion of SEMS was attempted in 12 patients. Successful stent placement was achieved in 10 of the 12 patients. The locations of lesions were hepatic flexure (2), splenic flexure (1), left colon (1), sigmoid colon (4) and rectum (4). The intended uses of SEMS were for palliation in 3 patients and as a bridge to elective surgery in 9. In the latter group, SEMS placement allowed for preoperative bowel preparation in 4 patients and administration of neoadjuvant therapy prior to elective surgery in 2 patients. One patient died prior to definitive surgery. Stent placement was unsuccessful in 2 patients. Three SEMS-related complications occurred; 1 stent migrated and 1 stent obstructed secondary to tumor ingrowth. One patient died 13 days after stent placement and colonic decompression. CONCLUSION: SEMS represent a useful tool in the management of obstructing colorectal neoplasms. As a bridge to surgery, SEMS provide time for a complete preoperative evaluation and a mechanical bowel preparation and may obviate the need for fecal diversion or on-table lavage. It may also allow for time to administer neoadjuvant therapy when indicated. As a palliative measure, SEMS can eliminate the need for an operation.

Influence of arginine dietary supplementation on healing colonic anastomosis in the rat.

INTRODUCTION: This study sought to determine whether dietary arginine influences colonic anastomotic healing in the rat model. METHODS: Three groups of 42 Sprague-Dawley rats were fed 0, 1, and 3 percent arginine diets for three preoperative and three postoperative days. Animals underwent transection of the transverse colon with hand-sewn anastomosis. Subgroups of 14 animals in each dietary group were killed on postoperative Days 6, 10, or 14, and bursting pressures, histologic inflammation, and collagen content were compared. RESULTS: Mean anastomotic bursting pressures on postoperative Day 6 were lower for the 0 percent arginine group than the 1 and 3 percent arginine groups (mean +/- standard error of the mean = 134+/-6 mm Hg, 164+/-7 mm Hg, and 166+/-7 mm Hg, respectively; P<0.0005). On Days 10 and 14, no significant differences in bursting pressures were noted between arginine diets. Mean bursting pressures on postoperative Day 6 (155+/-4 mm Hg) were significantly lower than on Days 10 (204+/-5 mm Hg) and 14 (217+/-6 mm Hg; P<0.001) for all arginine diets. Microscopic evaluation of the anastomoses did not show significant differences in inflammation or collagen content between arginine diets. Collagen content in all dietary groups peaked at Day 10. CONCLUSIONS: Perioperative arginine deficiency in the rat model is associated with impaired anastomotic healing during the first week, as reflected by lower bursting pressures. Arginine supplementation to 3 percent does not improve bursting pressures above those found in the usual 1 percent arginine diet at 6, 10, or 14 days. Bursting pressures plateau by Day 10 regardless of perioperative dietary arginine, whereas collagen content peaks at Day 10 after six-day perioperative arginine diet manipulation.

Colorectal cancer in hereditary breast cancer kindreds.

PURPOSE: This study compared characteristics of colorectal cancer between families with dominant breast cancer inheritance and the general population. The cumulative incidence of colorectal cancer was also studied in genetically determined breast cancer syndrome subjects with BRCA1 and BRCA2 mutations and compared with the general population. METHODS: Subjects included 42 patients with colorectal cancer from 32 clinically determined hereditary breast cancer kindreds based on the autosomal dominant inheritance of breast cancers and early age of onset. The general population colorectal cancer cohort was composed of 755 patients from a tumor registry. Lifetime risk of colorectal cancer was determined in 164 BRCA1 and 88 BRCA2 gene mutation carriers and compared with the general population. Mean age of colorectal cancer onset, anatomic site distribution, histologic stage at presentation, and five year stage-stratified survival rates were compared between clinically determined hereditary breast cancer family members and the general population. RESULTS: The lifetime risk of colorectal cancer in male BRCA1 and BRCA2 mutation carriers was 5.6 percent, which was not different from 6 percent in males from the general population. Likewise, the lifetime colorectal cancer risk in female BRCA1 and BRCA2 mutation carriers was 3.2 percent, which was not different from 5.9 percent in females from the general population. Mean age of onset +/- standard error for patients with colorectal cancer was 60 +/- 2 years for hereditary breast cancer kindreds compared with 67 +/- 0.4 years for the general population (P = 0.0004). Colorectal cancer site distribution did not vary between hereditary breast cancer and the general population. Overall colorectal cancer stage distribution was significantly different, with more Stage I and fewer Stage IV cancers in subjects with hereditary breast cancer compared with the general population (P = 0.01). Overall five year stage-stratified colorectal cancer survival rate +/- standard error was 66 +/- 8 percent for hereditary breast cancer kindreds and 46 +/- 2 percent for the general population (P = 0.023). CONCLUSION: Lifetime cumulative colorectal cancer incidence in subjects with BRCA1 and BRCA2 gene mutations was not different from the general population. However, significant differences in colorectal cancer were noted between hereditary breast cancer family members and the general population. Hereditary breast cancer-associated colorectal cancer had an earlier age of onset, lower tumor stage, and better survival rate than the general population. Except for age of onset, colorectal cancer in hereditary breast cancer kindreds exhibited more favorable characteristics than colorectal cancer in the general population.

Histologic comparison of hereditary nonpolyposis colorectal cancer associated with MSH2 and MLH1 and colorectal cancer from the general population.

PURPOSE: Hereditary nonpolyposis colorectal cancer is reported to have special histologic features. This study compares the histologic features of hereditary nonpolyposis colorectal cancer to colorectal cancers from the general population when hereditary nonpolyposis colorectal cancer cases are restricted to families with known MSH2 and MLH1 mutations. METHODS: Thirty-seven cancers from kindreds carrying MSH2 mutations, 27 cancers from kindreds carrying MLH1 mutations, and 37 colorectal cancers from the general population were reviewed by a pathologist blinded to hereditary nonpolyposis colorectal cancer gene status. Tumor grade, growth pattern, Crohn's-like lymphoid reaction, mucin production, extent of disease in the bowel wall, and lymph node status were evaluated. RESULTS: Poor differentiation and Crohn's-like reaction were a feature of 44 and 49 percent of hereditary nonpolyposis colorectal cancer compared with 14 percent (P = 0.002) and 27 percent (P = 0.049) of colorectal cancers from the general population, respectively. There was no difference in growth pattern, mucin production, lymph node involvement, or local extent of disease between hereditary nonpolyposis colorectal cancer and colorectal cancers from the general population. Poor differentiation and lymph node metastases were found in 57 and 49 percent of MSH2 compared with 26 percent (P = 0.002) and 10 percent (P = 0.03) of MLH1-associated cancers, respectively. There was no difference in growth pattern, mucin production, Crohn's-like lymphoid reaction, or local extent of disease between subgroups of hereditary nonpolyposis colorectal cancer. CONCLUSIONS: Poor differentiation and Crohn's-like reaction are more common in hereditary nonpolyposis colorectal cancer than colorectal cancers from general population. Poor differentiation and lymph node metastases are more commonly seen in MSH2-associated cancers than MLH1. Evaluation of the natural history, pathogenesis, and prognosis of colorectal cancer in hereditary nonpolyposis colorectal cancer should include consideration of which mismatch repair genes are mutated and what the specific mutations are.

Use of preoperative ultrasound staging for treatment of rectal cancer.

INTRODUCTION: Transrectal ultrasound is the standard method for preoperative staging of rectal cancer. This study reviews the accuracy of transrectal ultrasound staging for T3 disease and its use in the selection of patients for neoadjuvant chemoradiation. METHODS: One hundred seventeen patients underwent preoperative transrectal ultrasound evaluation for rectal cancer. Accuracy of transrectal ultrasound was evaluated among 70 patients not receiving preoperative chemoradiation. Forty-seven patients received neoadjuvant chemoradiation based on transrectal ultrasound results. Tumor downstaging and early recurrence were evaluated among 45 of 47 patients receiving neoadjuvant chemoradiation. RESULTS: Among 70 nonirradiated patients, 19 were pathologic Stage pT3. Transrectal ultrasound correctly identified 18 of 19 patients with Stage pT3 (sensitivity, 94.7 percent). Transrectal ultrasound correctly identified 44 of 51 patients with less than pT3 disease (specificity, 86.3 percent). After preoperative chemoradiation in 45 patients with ultrasound Stage uT3 or uT4 tumors, 56 percent of them experienced a reduction in T stage. Residual nodal disease was found in 31 percent of patients. A complete pathologic response with no residual disease at operation was observed in 22 percent of patients. During a median follow-up period of 21 months after diagnosis, seven patients experienced a recurrence of their disease at a median of 12 months after diagnosis. Five of seven patients with recurrence were among a subgroup of ten patients who both failed to downstage T and had residual nodal disease at operation. CONCLUSION: Transrectal ultrasound is an accurate modality for selecting patients for neoadjuvant treatment. Preoperative chemoradiation produced downstaging in 56 percent of patients. Factors related to early recurrence included residual nodal disease and failure to downstage T after neoadjuvant chemoradiation.

Cumulative incidence of colorectal and extracolonic cancers in MLH1 and MSH2 mutation carriers of hereditary nonpolyposis colorectal cancer.

The extracolonic tumor spectrum of hereditary nonpolyposis colorectal cancer (HNPCC) includes cancer of the endometrium, ovaries, stomach, biliary tract, and urinary tract. This study was designed to determine the penetrance of colorectal and extracolonic tumors in HNPCC mutation carriers. Forty-nine patients (22 females and 27 males) were identified with an MSH2 germline mutation, and 56 patients (28 females and 28 males) were identified with an MLH1 I mutation. Cumulative incidence by age 60 (lifetime risk) and mean age of cancer diagnosis were compared. The lifetime risk of extracolonic cancers in MSH2 and MLH1 carriers was 48% and 11%, respectively (P = 0.016). Extracolonic cancer risk in MSH2 females and males was 69% and 34%, respectively (P = 0.042). Mean age of extracolonic cancer diagnosis was significantly older for MSH2 males than females (55.4 vs. 39.0, P = 0.013). No difference was observed in colorectal cancer risk between MLH1 and MSH2 carriers (84% vs. 71%). Colorectal cancer risk was 96% in MSH2 males compared to 39% in MSH2 females (P = 0.034). No differences in colorectal and extracolonic cancer risks between MLH1 females and males were identified. The risk of extracolonic cancer by age 60 was greater in MSH2 mutation carriers than in MLH1 carriers. Gender differences in colorectal and extracolonic cancer risk were observed for MSH2 carriers only. These phenotypic features of HNPCC genotypes may have clinical significance in the design of genotype-specific screening, surveillance, and follow-up for affected individuals.

Ileoanal pouch function and release of peptide YY.

PURPOSE: This study evaluates peptide tyrosine-tyrosine (PYY), intestinal transit, fecal retention time, and anal sphincter manometry in colectomized patients with ileal pouch-anal anastomosis. METHODS: Plasma and pouch PYY, mouth-to-pouch transit time, fecal retention time, and anal canal pressures were studied in 27 patients with ileoanal pouches a mean of 50 (range, 3-84) months after loop ileostomy closure. RESULTS: Basal and peak postprandial plasma PYY were significantly reduced in patients with pouches compared with controls (P < 0.0001). Pouch PYY was decreased compared with control ileal PYY (P = 0.0003). No significant correlation was noted between intestinal transit and total integrated PYY response in patients with pouches (r=0.36; P=0.06). Fecal retention time was related to postprandial total integrated response of plasma PYY (r=0.43; P=0.02), mouth-to-pouch transit (r=0.87; P < 0.0001), and resting (r=0.44; P=0.02) and squeeze (r=0.62; P=0.0006) anal sphincter pressures. CONCLUSIONS: Colectomized ileoanal patients with pouches showed decreased plasma and pouch PYY compared with controls. Intestinal transit was not significantly related to PYY release. However, prolonged pouch fecal retention was associated with greater PYY release, mouth-to-pouch transit, and anal sphincter pressures.

Colorectal and extracolonic cancer variations in MLH1/MSH2 hereditary nonpolyposis colorectal cancer kindreds and the general population.

PURPOSE: This clinical case review aimed to identify phenotypic variations in colorectal and extracolonic cancer expression between hereditary nonpolyposis colorectal cancer (HNPCC) families with MLH1 and MSH2 germline mutations and the general population. METHODS: Colorectal cancer onset and site distribution were compared among 67 members of MLH1 kindreds, 45 members of MSH2 kindreds, and 1,189 patients from the general population. Synchronous and metachronous cancer rates, tumor stage, extracolonic cancer incidence, and survival were also compared. RESULTS: Mean ages of colorectal cancer onset were 44, 46, and 69 years for MLH1, MSH2, and the general population, respectively (P < 0.001). More proximal and fewer distal colon cancers were noted in HNPCC than the general population (P < 0.001, P = 0.04). Site distribution showed disparity of rectal cancers (8 percent MLH1 vs. 28 percent MSH2; P = 0.01) based on genotypes. Overall, synchronous colorectal cancer rates were 7.4, 6.7, and 2.4 percent for MLH1, MSH2, and the general population, respectively (P = 0.016). Annual metachronous colorectal cancer rates were 2.1, 1.7, and 0.33 percent for MLH1, MSH2, and the general population, respectively (P = 0.041). Colorectal cancer stage presentation was lower in HNPCC than the general population (P = 0.0028). Extracolonic cancers were noted in 33 percent of MSH2 patients, compared with 12 percent of MLH1 patients and 7.3 percent of the general population with colorectal cancers (P < 0.001). Combined MLH1 and MSH2 ten-year survival was 68.7 percent compared with 47.8 percent for the general population (P = 0.009 stage stratified, hazard ratio 0.57). CONCLUSION: The presence of rectal cancer should not preclude the diagnosis of HNPCC, because the incidence of rectal cancer in MSH2 was comparable with that in the general population. Phenotypic variations, including the preponderance of extracolonic cancers in MSH2 patients, did not result in survival differences between genotypic subgroups. These phenotypic features of HNPCC genotypes may have clinical significance in the design of specific screening, surveillance, and follow-up for affected individuals.

Pudendal nerve function in normal and encopretic children.

BACKGROUND: Abnormal pudendal nerve function contributes to fecal retention and incontinence in adults. To determine the role of pudendal neuropathy in childhood, we prospectively evaluated pudendal nerve function in normal and encopretic children. METHODS: We studied pudendal nerve terminal motor latency in 23 encopretic children and in an equal number of similarly aged, normal children. Anal manometry and electromyography were also obtained in all children. RESULTS: Pudendal nerve latency in the encopretic children equaled 1.58 +/- 0.33 msec, which was the same as that in control children. Of the 75 pudendal nerves tested, latency was prolonged in only one encopretic child. In contrast, anal electromyography demonstrated nonrelaxation of the external anal sphincter in 75% of the encopretic children but in only 13% of the normal children (p < 0.001). Anorectal manometry demonstrated, on average, lower and sphincter pressures at rest and with squeezing in the encopretic children (p < 0.01), but only 17% had sphincter pressures more than two standard deviations below normal. CONCLUSIONS: Other than poor relaxation response of the external anal sphincter during evacuation, these data reveal a paucity of functionally important abnormalities in encopretic children. In particular, we find no evidence that abnormal pudendal nerve function is important in the etiology or pathogenesis of encopresis in children.

Transanal ultrasound and anorectal physiology findings affecting continence after sphincteroplasty.

PURPOSE: This study was undertaken to evaluate endosonographic and physiologic determinants of fecal continence after sphincteroplasty. METHODS: Sixteen female patients with severe fecal incontinence were treated with overlapping sphincteroplasty. Mean postoperative follow-up was 12 (range, 3-48) months. All patients underwent preoperative and postoperative transanal endosonography and anal manometry. Bilateral pudendal nerve terminal motor latency determinations were performed in each patient. A physiologic continence score was used to assess stool control. RESULTS: Postoperatively, continence was worse, unchanged, and improved in one, five, and ten patients, respectively. An inverse correlation was noted between endosonographic sphincter discontinuity postoperatively, in degrees, and the change in fecal continence after overlapping sphincteroplasty (r = -0.51; P = 0.04). Postoperative increases in sphincter resting (r = 0.6; P = 0.02) and squeeze (r = 0.54; P = 0.03) pressures correlated with improved fecal continence. Mean pudendal nerve terminal motor latency (r = -0.34; P = 0.20) and changes in anal sphincter length at rest (r = 0.41; P = 0.11) and squeeze (r = 0.33; P = 0.20) after sphincteroplasty did not significantly correlate with the change in continence. Patients with intact endosonographic anatomy postoperatively and bilateral, unilateral, or no evidence of pudendal neuropathy had a mean change in continence score of 0.5, 1.8, and 2.2, respectively (P = 0.48). CONCLUSIONS: Endosonography after sphincteroplasty can identify residual sphincter defects that are significant in terms of fecal continence. Restoration of anal canal resting and squeeze pressures was related to improved fecal control after overlapping sphincteroplasty. Mean pudendal nerve terminal motor latency was not significantly related to poor postoperative continence. A trend toward less improvement in fecal continence was noted with bilateral pudendal neuropathy.

Electron microscopic differentiation of directly and transneuronally transported DiI and applications for studies of synaptogenesis.

The neuronal tracer DiI is a lipophilic dye which diffuses along the lipid bilayer of membranes and sometimes will move transcellularly. We used this tracer to study the development of olivocochlear synapses in the auditory system in rats and chickens by applying DiI directly to severed axons in the olivocochlear bundle. Observations with epi-fluorescent microscopy showed that DiI had labelled efferent axons directly and had labelled spiral ganglion cells and hair cells transneuronally. Ultrastructural analysis of photoconverted DiI tissue in rats revealed that transneuronal diffusion occurred when the plasma membrane of directly labelled axons made contact with the plasma membrane of their target structure. Directly and transneuronally labelled profiles can be distinguished easily at the electron microscopic level. In directly labelled profiles, all plasma, nuclear, endoplasmic reticulum, and outer mitochondrial membranes and cell cytoplasm are labelled leaving only the mitochondrial matrix unstained. However, in transneuronally labelled cells the endoplasmic, nuclear, and immature synaptic membranes are labelled but mitochondrial and non-synaptic plasma membranes are not labelled. This labelling pattern can be explained by diffusion through continuous membranes. These characteristics make DiI diffusion a powerful technique for identifying and studying early events in neuronal development and synapse formation.

Cloning and nucleotide sequence analysis of a Brucella abortus gene encoding an 18 kDa immunoreactive protein.

A DNA fragment encoding an approximately 18 kDa protein from Brucella abortus strain 2308 was cloned and expressed in Escherichia coli. This recombinant protein, designated BA18K, reacted in Western blot analysis with sera obtained from experimentally and naturally infected animals including mice, goats, dogs and humans. Restriction enzyme analysis of the plasmid (pBA28) encoding BA18K revealed the presence of an approximately 8.7 kbp Sau3A genomic DNA fragment within the vector and subsequent subcloning and Western blot analysis limited the region encoding BA18K to an approximately 3.0 kbp Pst 1 DNA fragment. DNA sequence analysis of this region identified an open reading frame capable of encoding a protein of 177 amino acids with a predicted relative molecular mass of 17529. Comparison of the deduced amino acid sequence of BA18K with those in the protein sequence databases yielded no homology with previously described proteins from other bacterial genera. These searches did, however, indicate that BA18K is identical to the previously described outer membrane protein (OMP) from B. abortus strain 544 designated Omp 19.

Diagnosing anal sphincter injury with transanal ultrasound and manometry.

PURPOSE: This study was undertaken to evaluate how well anorectal manometry and transanal ultrasonography diagnose anal sphincter injury. METHODS: Anorectal manometry and transanal ultrasonography were performed in 20 asymptomatic nulliparous women and 20 asymptomatic parous women, and the results were compared with those obtained in 31 incontinent women who subsequently underwent sphincteroplasty and, thus, had operatively verified anal sphincter injury. By using computerized manometry analysis, mean maximum resting and squeeze pressures, sphincter length, and vector symmetry were determined in all women. All transanal ultrasounds were interpreted blinded as to the patient's history, physical examination, and manometry results. RESULTS: Manometric resting and squeeze pressures were significantly higher in the asymptomatic nulliparous women than in the asymptomatic parous women, and both groups had significantly higher pressures than the incontinent women (P < 0.001). Anal sphincter length and vector symmetry index were significantly decreased in incontinent women compared with asymptomatic women (P < 0.01). Decreased resting and squeeze pressures suggestive of possible sphincter injury were found in 90 percent of incontinent women with known anal sphincter injury. Decreased anal sphincter length and vector symmetry were found in only 42 percent of women with known anal sphincter injury. Transanal ultrasound was able to identify 100 percent of the known sphincter injuries but also falsely diagnosed injury in 10 percent of the asymptomatic nulliparous women with intact anal sphincters. False identification of sphincter injury increased when transanal ultrasound scanning was performed proximal to the distal 1.5 cm of the anal canal. CONCLUSION: Although nonspecific, decreased resting and squeeze pressures were found in 90 percent of patients with anal sphincter injury. Decreased anal sphincter length or vector symmetry index were present in only 42 percent of patients with known sphincter injury. When limited to the distal 1.5 cm of the anal canal, transanal ultrasound identified all known sphincter injuries but falsely identified injury in 10 percent of women with intact anal sphincters. Transanal ultrasound in combination with decreased anal pressures correctly identified all intact sphincters and 90 percent of known anal sphincter injuries.

Operative results of House advancement anoplasty.

A retrospective review of 29 patients who had an anoplasty using the sliding House advancement flap was carried out to evaluate the efficacy and safety of this new technique. Long-term symptom relief and late complications were determined by telephone interview. Indications for anoplasty were: stenosis (21 cases), ectropion (four), Bowen's disease (two), keyhole deformity (two) and perineal fistula (one). A single House flap was performed in most patients, but eight required multiple flaps. Lateral internal sphincterotomy was performed concomitantly in 16 of 21 patients with anal stenosis. Postoperative complications included donor-site separation (14), urinary retention (eight) and sepsis (four). At a median follow-up of 28 months, 26 of 29 patients had improved and 24 were completely satisfied. House flap anoplasty can be used to correct many anoderm deficiencies with a high rate of success and patient satisfaction.

Preoperative chemoradiation downstages locally advanced ultrasound-staged rectal cancer.

BACKGROUND: This prospective study assessed the effect of preoperative radiation and chemotherapy on the pathologic staging of advanced rectal cancer. METHODS: Twenty patients with rectal cancer were treated with combined chemoradiation prior to operation, after pretreatment staging of all lesions with transrectal ultrasound (TRUS). Perirectal fat invasion served as minimal criteria for preoperative neoadjuvant therapy. The pretreatment stage of these rectal lesions as defined by TRUS was then compared with the pathological stage of the surgical specimen following resection. Cancers were treated with high-dose radiation (45 to 54 Gy) in 19 of 20 patients. One patient received in excess of 60 Gy because of tumor characteristics. Chemotherapy consisted of 5-fluorouracil delivered as a continuous infusion or bolus therapy. Four to 8 weeks after neoadjuvant therapy, 13 abdominal perineal resections, 5 low anterior resections, and 2 completion proctectomies were performed. RESULTS: Following resection, rectal cancer was downstaged in 14 of 20 patients. No tumor was present in the rectal wall in 8 of 20 patients. Complete pathological response was present in 7 of 20 patients. Local recurrence occurred in 2 of 20 patients. Disease-free survival in the remaining 17 of 20 patients ranges from 9 to 51 months (average 26). CONCLUSIONS: Preoperative chemoradiation in the surgical management of advanced rectal cancer results in demonstrable tumor downstaging.