Histaminergic descending inputs to the mesopontine tegmentum and their role in the control of cortical activation and wakefulness in the cat

We have demonstrated previously the importance of histaminergic neurons in arousal mechanisms. In addition to their ascending axons, these neurons also send heavy descending inputs to the mesopontine tegmentum (MPT), which plays a key role in cortical activation during wakefulness (W). This anatomical link suggests histaminergic control of the mechanisms of the MPT relevant to behavioral states. In this study, we sought to demonstrate, at the light microscopy level, hypothalamotegmental histaminergic pathways and their topographical interaction with MPT neurons in the cat and to explore further their involvement in sleep-wake control. Using immunohistochemistry of histamine (HA), either alone or together with that of choline-acetyltransferase or tyrosine hydroxylase, a large number of very fine, short and varicose HA-positive fibers and terminal-like dots were detected in the MPT, including the laterodorsal tegmental nucleus, locus coeruleus (LC), LC alpha, and peri-LC alpha. Furthermore, these fibers and terminal-like structures were found in close proximity to a great number of cholinergic or noradrenergic neurons. We also investigated the effects of microadministration of HA agonists and antagonist into the mediodorsal pontine tegmentum on the cortical electroencephalogram (EEG) power spectra and the sleep-wake cycle in freely moving cats. Microinjection of HA or 2-thiazolylethylamine (an H1-receptor agonist) caused a long-lasting suppression of cortical slow activity and an increase in quiet wakefulness (W). Paradoxical sleep, however, was less affected. The effects of HA were attenuated by systemic or in situ pretreatment with mepyramine (an H1-receptor antagonist), which when injected alone produced an increase in slow wave sleep. Microinjection of impromidine (an H2-receptor agonist) into the same area had no effect on either the cortical EEG or W. Because MPT ascending and presumed cholinergic neurons discharge tonically during cortical activation of W and because HA causes excitation of MPT cholinergic neurons via H1 receptors, we hypothesize that the histaminergic descending afferents in the MPT would promote cortical desynchronization and W, at least partially, via activation of H1 receptors situated on cholinergic neurons and that the interactions between histaminergic and cholinergic neurons constitute an important circuit in cortical activation during W.

The rabbit as an intracavernous injection study model

We investigated the feasibility of using the rabbit as an animal model for intracavernous injection studies. The rabbit, having a penile structure rather similar to that of humans, offers the advantage of being a strain-specific, adequately sized, and easily controlled experimental animal. Using intracavernous injections of the two vasoactive drugs prostaglandin E1 (PGE1, 0.2-1.6 micrograms/kg) and papaverine (PAP, 0.25-1 mg/kg), which have been commonly used in the management of erectile dysfunction in man, increases intracavernous pressure (delta ICP) were induced. After intracavernous injection of PGE1, the maximal delta ICP ranged from 18 to 44 mmHg (mean 29.25 +/- 7.85 mmHg) with a duration of tumescence from 3.1 to 13.3 min (mean 8.61 +/- 3.71 min). Intracavernous injection of PAP also induced increases in ICP, with a maximal delta ICP ranging from 24 to 56 mmHg (mean 43.5 +/- 11.35 mmHg) and a duration of tumescence from 5.3 to 15 min (mean 10.25 +/- 3.39 min). The systemic blood pressures were unchanged after all intracavernous injections. In addition, administration of cAMP antagonist in combination with PGE1 inhibited the relaxing effects of PGE1 in a dose-dependent manner. Our results suggest that the effects of vasoactive drugs on the rabbit's corpus cavernosum are similar to those in humans; thus the rabbit model is a suitable alternative for further physiological and pharmacological studies of penile erection.

Implications of urinary basic fibroblast growth factor excretion in patients with urothelial carcinoma

1. Angiogenesis occurs in response to wounding, and is of vital importance for tumour growth and metastasis. Basic fibroblast growth factor, a well-known angiogenic factor, has been suggested to be a urine marker for urothelial carcinoma. However, the relevance of its detection has not been evaluated in a large number of patients. 2. Immunoassay of basic fibroblast growth factor was performed on urine samples from different aetiologies of urothelial disorder. Expression of basic fibroblast growth factor in the corresponding tumour was correlated with the urine level. 3. The excretion of basic fibroblast growth factor (ng/g creatinine) was significantly elevated in both inflammatory and neoplastic urological diseases compared with normal individuals (P < 0.05), while it was normalized in tumour-free subjects (P < 0.01). Receiver operating characteristic plotting revealed a sensitivity of 40% for tumour diagnosis at the cut-off point of 3.29 ng/g creatinine. The sensitivity of the test in predicting tumour recurrence was only 14%. The basic fibroblast growth factor level in urine showed a positive association with increasing age of cancer patients (P = 0.02) and with tumour grading (P = 0.05). However, no important relationship was observed regarding tumour stage, size, number, shape or degree of local inflammatory reaction (P > 0.01). Pairwise analysis of the basic fibroblast growth factor level in urine and its expression in corresponding tumours did not reveal a conspicuous correlation (r = -0.097, P = 0.43). 4. Our results suggested that estimation of urinary basic fibroblast growth factor cannot be satisfactory as a tumour marker. The measurement may represent one of the tissue responses to injury or the host-tumour interactions. A longitudinal study is required to elucidate the role of basic fibroblast growth factor in order to select the appropriate treatment strategy for urothelial carcinoma.

The application of competitive Hopfield neural network to medical image segmentation

In this paper, a parallel and unsupervised approach using the competitive Hopfield neural network (CHNN) is proposed for medical image segmentation. It is a kind of Hopfield network which incorporates the winner-takes-all (WTA) learning mechanism. The image segmentation is conceptually formulated as a problem of pixel clustering based upon the global information of the gray level distribution. Thus, the energy function for minimization is defined as the mean of the squared distance measures of the gray levels within each class. The proposed network avoids the onerous procedure of determining values for the weighting factors in the energy function. In addition, its training scheme enables the network to learn rapidly and effectively. For an image of n gray levels and c interesting objects, the proposed CHNN would consist of n by c neurons and be independent of the image size. In both simulation studies and practical medical image segmentation, the CHNN method shows promising results in comparison with two well-known methods: the hard and the fuzzy c-means (FCM) methods.

Reduction of false positives in lung nodule detection using a two-level neural classification

The authors have developed a neural-digital computer-aided diagnosis system, based on a parameterized two-level convolution neural network (CNN) architecture and on a special multilabel output encoding procedure. The developed architecture was trained, tested, and evaluated specifically on the problem of diagnosis of lung cancer nodules found on digitized chest radiographs. The system performs automatic "suspect" localization, feature extraction, and diagnosis of a particular pattern-class aimed at a high degree of "true-positive fraction" detection and low "false-positive fraction" detection. In this paper, the authors aim at the presentation of the two-level neural classification method in reducing false-positives in their system. They employed receiver operating characteristics (ROC) method with the area under the ROC curve (A(z)) as the performance index to evaluate all the simulation results. The two-level CNN showed superior performance (A(z)=0.93) to the single-level CNN (A(z)=0.85). The proposed two-level CNN architecture is proven to be promising and to be extensible, problem-independent, and therefore, applicable to other medical or difficult diagnostic tasks in two-dimensional (2-D) image environments.

Prognostic factors of primary transitional cell carcinoma of the upper urinary tract

OBJECTIVES

We presented and analyzed our results in order to determine the relationship between patient survival and tumor grade and/or stage. In addition, a retrospective tumor DNA ploidy study was done to evaluate its possible role in predicting future tumor recurrence in the bladder.

METHODS

A total of 112 patients with upper urinary tract transitional cell carcinomas (TCCs) were recorded at our hospital. Of these, 68 patients without concurrent bladder tumors (ages ranged from 36 to 80, mean 62.4 years; male:female = 1:1.2) were treated by nephroureterectomy and bladder cuff resection. They were followed up for 14-79 months (average 38.2 months). Eight (36.4%) of the 22 patients who had stage C or D tumors had received adjuvant systemic methotrexate, vinblastine, epirubicin, cisplatin chemotherapy after surgery. DNA flow cytometry using paraffin-blocked tumor specimens was performed on the tumors of 52 patients.

RESULTS

Their pathologic stages and grades were 11 at stage 0, 15 at stage A, 20 at stage B, 14 at stage C, 8 at stage D; 9 of grade I, 41 of grade II, and 18 of grade III. Postoperatively, 13 patients (19.1%) subsequently developed bladder tumors with a latent period ranging from 2 to 37 months (average 14.9 months). The difference of the tumor DNA ploidy distribution pattern among tumors of high versus low stages and/or grades is not statistically significant (p > 0.05). Overall, the 5-year survival rates for patients with low- and high-stage tumors were 100 and 66.7%, respectively; for patients with grade I-II and III tumors they were 93.6 and 28.3%, respectively.

CONCLUSIONS

Patient survival was mainly related to both tumor stages (p = 0.0037) and grades (p = 0.0001), rather than to tumor DNA ploidy. For patients with grade II upper urinary tract tumors, tumor DNA ploidy seems to provide no additional predictive value on subsequent tumor recurrence in the bladder.

The half-moon sign. A useful roentgen sign of saccular aneurysm of the aortic arch

OBJECTIVE

The half-moon sign is defined as a shadow seen on the lateral chest radiograph consisting of a smooth, partially demarcated opacity with the rounded portion of the half moon projecting over the aortic lumen at the level of the aortic arch, but the rest of the opacity merging with the aorta. In this study, we intended to evaluate the clinical usefulness of half-moon sign in aiding a diagnosis of saccular aneurysm of the aortic arch.

METHODS

This series consisted of 57 patients with aortic arch aneurysm and 46 patients with a variety of nonvascular intrathoracic masses that presented as soft-tissue masses adjacent to the aortic arch on the frontal chest radiographs. The half-moon sign was evaluated independently by two senior chest radiologists who had no knowledge of the final causes.

RESULTS

The half-moon sign was shown on the lateral chest radiographs in 5 of 10 patients with saccular aortic arch aneurysm but absent in 47 patients with fusiform aortic arch aneurysm. Furthermore, this roentgen sign was not seen on the lateral chest radiographs in 46 patients with nonvascular intrathoracic masses. In this selected population, the sensitivity and specificity of the half-moon sign in aiding a diagnosis of saccular aneurysm of the aortic arch were 50% and 100%, respectively.

CONCLUSION

The half-moon sign shown on the lateral chest radiograph is highly suggestive of the saccular aortic arch aneurysm.

Allogeneic peripheral blood progenitor cell transplant after bone marrow graft failure: report of a case

A 31-year-old woman diagnosed with acute myelocytic leukemia received an allogeneic peripheral blood progenitor cell (PBPC) transplant one month after a previous bone marrow graft failed. PBPCs were mobilized with granulocyte-colony-stimulating factor and collected by apheresis. T-cell depletion was not performed and no further chemo- or radiotherapy was given for the second transplant. Engraftment was prompt, with the peripheral blood leukocyte count rising dramatically to 2,400/microL, six days after completion of PBPC transplant. The platelet count reached 36,000/microL on the eighth day and was self-sustained thereafter. Both blood grouping and bone marrow karyotyping confirmed donor origin of the engraftment. At the time of writing, the patient has been disease-free for over 200 days without any complications of acute or chronic graft-versus-host disease.

Differentiation between nodules and end-on vessels using a convolution neural network architecture

In recent years, many computer-aided diagnosis schemes have been proposed to assist radiologists in detecting lung nodules. The research efforts have been aimed at increasing the sensitivity while decreasing the false-positive detections on digital chest radiographs. Among the problems of reducing the number of false positives, the differentiation between nodules and end-on vessels is one of the most challenging tasks performed by computer. Most investigators have used a conventional two-stage pattern recognition approach, ie, feature extraction followed by feature classification. The performance of this approach depends totally on good feature definition in the feature extraction stage. Unfortunately, suitable feature definition and corresponding extraction implementation algorithms proved to be very difficult to define and specify. A convolution neural network (CNN) architecture, trained by direct connection to the raw image is proposed to tackle the problem. The CNN, which uses locally responsive activation function, is directly and locally connected to the raw image. The performance of the CNN is evaluated in comparison to an expert radiologist. We used the receiver operating characteristics (ROC) method with area under the curve (Az) as the performance index to evaluate all the simulation results. The CNN showed superior performance (Az = 0.99) to the radiologist's (Az = 0.83). The CNN approach can potentially be applied to other applications, such as the differentiation of film defects and microcalcifications in mammography, in which the image features are difficult to define or not known a priori.

The inflammatory cytokine response to Chlamydia trachomatis infection is endotoxin mediated

Chlamydia trachomatis is a major etiologic agent of sexually transmitted diseases. Although C. trachomatis is a gram-negative pathogen, chlamydial infections are not generally thought of as endotoxin-mediated diseases. A molecular characterization of the acute immune response to chlamydia, especially with regard to the role of its lipopolysaccharide (LPS), remains to be undertaken. We extracted 15 mg of LPS from 5 x 10(12) C. trachomatis elementary bodies (EB) for analysis of structure and biological activity. When methylated lipid A was subjected to high-pressure liquid chromatography followed by mass spectrometry, the majority of the lipid A was found to be pentaacyl. The endotoxin activities of whole C. trachomatis EB and purified LPS were characterized in comparison with whole Salmonella minnesota R595 and with S. minnesota R595 LPS and lipooligosaccharide from Neisseria gonorrhoeae. Both C. trachomatis LPS and whole EB induced the release of tumor necrosis factor alpha from whole blood ex vivo, and C. trachomatis LPS was capable of inducing the translocation of nuclear factor kappa B in a Chinese hamster ovary fibroblast cell line transfected with the LPS receptor CD14. In both assays, however, C. trachomatis was approximately 100-fold less potent than S. minnesota and N. gonorrhoeae. The observation that C. trachomatis is a weak inducer of the inflammatory cytokine response correlates with the clinical observation that, unlike N. gonorrhoeae infection, genital tract infection with C. trachomatis is often asymptomatic. The ability of specific LPS antagonists to completely inhibit the tumor necrosis factor alpha-inducing activity of whole C. trachomatis EB suggests that the inflammatory cytokine response to chlamydia infection may be mediated primarily through LPS. This implies that the role of other surface protein antigens, at least in terms of eliciting the proinflammatory cytokine response, is likely to be minor.

Safety profile of over-the-counter naproxen sodium

The safety of naproxen sodium for over-the-counter use was evaluated based on 48 randomized, double-blind, placebo-controlled clinical trials that evaluated naproxen/naproxen sodium (NAP) for indications appropriate to, and under, conditions common to, nonprescription analgesics. Of the 48 studies, 27 were single-dose studies and 21 were multiple-dose studies of 1 to 10 days' duration; 19 studies included ibuprofen and 9 included acetaminophen. A total of 4138 patients received naproxen or naproxen sodium (3589 patients received naproxen 187.5 to 400 mg and 549 received naproxen sodium 220 to 440 mg), 2423 received placebo, 1574 received ibuprofen (200 or 400 mg), and 671 received acetaminophen (500 to 1000 mg). Adverse-event rates were examined in three sets of comparisons: NAP versus placebo (48 studies); NAP versus ibuprofen and placebo (19 studies); and NAP versus acetaminophen and placebo (9 studies). Across all 48 studies, 83% of both the NAP- and placebo-treated patients reported no adverse events. The incidence rates were similar between NAP and placebo, with headache (4.8% NAP, 6.4% placebo), nausea (3.4% NAP, 3.1% placebo), and somnolence (2.7% NAP, 1.9% placebo) the most commonly reported events. Rates of adverse events with NAP, ibuprofen, and acetaminophen were similar.

Clinical significance of urinary ferritin excretion in patients with transitional cell carcinoma

1. The serum ferritin level provides a valuable index of the body iron store. An increase in serum ferritin has often been observed in patients with neoplastic disease and correlates well with the stage of cancer. A few studies have suggested the potential of urinary ferritin as a marker for transitional cell carcinoma. The rationale of the measurement, however, has not been investigated in detail. 2. Urinary ferritin levels were evaluated in patients with diverse urological diseases to investigate their potential clinical implications. 3. Analysis of logarithmic transformed values (ng/mg creatinine) showed that patients with both neoplastic and non-neoplastic urological diseases had significantly higher ferritin levels than normal control subjects (P = 0.02). There was no apparent difference between subgroups of patients with urological disease (P > 0.5). For patients with urothelial carcinoma, univariate analysis revealed a strong positive relationship between urinary ferritin levels and the density of lymphoid cells in tumour stroma (P = 0.0001), while no important association was observed with tumour grade (P = 0.32), stage (P = 0.29) or urinary cytology detection (P = 0.33). Patients with muscle-invasive tumour had significantly higher ferritin levels than those with papillary, superficial cancer (P < 0.05). For patients with non-neoplastic urological disease (n = 19), urinary ferritin levels tend to correlate with the severity of tissue inflammation (P = 0.03). 4. The results suggest that urinary ferritin may reflect the degree of local inflammatory reaction in the urinary tract.(ABSTRACT TRUNCATED AT 250 WORDS)

Detubularized folded O-shaped ileal bladder

Using a submucosal needle tunneling technique for ureteral implantation, detubularized folded O-shaped ileal bladders were created for seven patients in need of bladder replacement. A segment of ileum of only 300 to 400 mm in length was required. Anastomosis of the reservoir to the urethra was simply performed by tailoring the ileum to reduce tension at the anastomosis site. Follow-up periods ranged from 24 to 46 months. Excellent upper tract function and good evacuation function with minimal residual urine were demonstrated. Urodynamic studies revealed a mean bladder capacity of 367 mL, with low intra-ileobladder pressure. All patients are continent during the day. Mild enuresis was noted in three patients. No reflux was noted on follow-up voiding cystourethrography. This type of ileal bladder is simple to create and provides reliable results. The presence of a short mesentery is not a serious limiting factor.

[Hemolytic disease of the newborn caused by maternal anti-Di(a): a case report in Taiwan]

The first case of hemolytic disease of the newborn (HDN) possibly caused by anti-Di(a) in a Chinese infant in Taiwan is reported. The mother had two pregnancies before but no history of blood transfusion. Her first male infant was normal, but her second full-term male one developed mild jaundice soon after birth, and the total bilirubin level was 12.1 mg/dL, 18.3 mg/dL, 23.6 mg/dL at 24 hours, 48 hours, and 72 hours of age, respectively. Total bilirubin was 9.1 mg/dL on the eighth day after receiving phototherapy and compatible blood exchange transfusion. The infant recovered uneventfully. The immunohematological study revealed that the mother was group AB, Rh (D)+; Di(a - b+), the father was group O, Rh (D)+; Di(a + b+), the infant boy and his 2-year-old brother were group B, Rh(D)+; Di(a + b+). The direct antiglobulin test (DAT) on the infant red cells was positive (4+ with polyspecific AHG; 4+ with anti-IgG). The maternal serum and infant's eluate from red blood cells showed negative reactions in routine antibody detection tests, but they contained alloantibody reacting against the Di(a+) cells by the manual polybrene test (MP) and indirect antiglobulin test (IAT) in AHG phase. The anti-Di(a) titers in the mother's serum was MP 1:256 and AHG 1:256, and in the infant's eluate was MP 1:128 and AHC 1:64 against Di(a + b+) cells. Based on the above results we conclude that the jaundice in this newborn baby was caused by maternal anti-Di(a) which was most likely induced by previous pregnancy. In conclusion, Diego blood group is a system of high value in anthropology because it accounts for the Mongoloid origin of American Indians, Japanese and Chinese. Anti-Di(a) may cause HDN, as in our case of HDN due to maternal anti-Di(a) in a Chinese infant. But in Europe and America, where practically all people are Di(a - b+) phenotypes, the system seems of no interest in parental studies as well as in blood transfusions. Owing to the Di(a) antigen is of higher incidence in Chinese population, we suggest that the Diego system should be involved in routine compatibility testing or antibody identification problems in parental studies and in blood transfusions in Taiwan.

The in vitro activity of beta-lactamase inhibitors in combination with cephalosporins against M. tuberculosis

Although there are reports that the addition of a beta-lactamase inhibitor to ampicillin or amoxicillin greatly improves their in vitro activity against M. tuberculosis, there are no written reports about the antituberculosis effects of beta-lactamase inhibitors in combination with cephalosporins against M. tuberculosis. In this report, we have determined the minimal inhibitory concentrations (MIC) of 5 cephalosporins with or without combination with beta-lactamase inhibitor against M. tuberculosis strains isolated from patients before antituberculosis treatment and checked the production of beta-lactamase by bacteria before this procedure. Four strains of M. tuberculosis were contaminated during the experiment, and all the other 16 strains hydrolyzed the nitrocefin disc, thus indicating a beta-lactamase producer. The MICs of cephalosporins alone against M. tuberculosis were 200-400 micrograms/ml for ceforanide, 100-400 micrograms/ml for cephapirin, 400-1600 micrograms/ml for cefamandole, 200-1600 micrograms/ml for cefotaxime, and 800-1600 micrograms/ml for ceftriaxone. After adding the equimolar concentrations of sulbactam, the MICs were reduced to 100-200 micrograms/ml for ceforanide, 12.5-100 micrograms/ml for cephapirin, 100-400 micrograms/ml for cefamandole, 25-200 micrograms/ml for cefotaxime, and 100-800 micrograms/ml for ceftriaxone. We concluded that sulbactam enhanced the antituberculosis effect of cephalosporins.

Incidence of internal cancers and ingested inorganic arsenic: a seven-year follow-up study in Taiwan

In order to elucidate the dose-response relationship between ingested inorganic arsenic and internal cancers, a total of 263 patients with blackfoot disease and 2293 healthy residents in the endemic area of arseniasis were recruited and followed up for 7 years. The information on consumption of high-arsenic artesian well water, sociodemographic characteristics, life-style and dietary habits, and personal and family history of cancers was obtained through standardized interviews. The occurrence of internal cancers among study subjects was determined through annual health examinations, home visit personal interviews, household registration data checks, and national death certification and cancer registry profile linkages. A dose-response relationship was observed between the long-term arsenic exposure from drinking artesian well water and the incidence of lung cancer, bladder cancer, and cancers of all sites combined after adjustment for age, sex, and cigarette smoking through Cox's proportional hazards regression analysis. Blackfoot disease patients had a significantly increased cancer incidence after adjustment for cumulative arsenic exposure.

Renal effects and urinary excretion of prostaglandin following indomethacin therapy in premature infants with patent ductus arteriosus

Renal side effects and urinary prostaglandin were evaluated in 10 premature infants (Mean +/- SD: BW 1245 +/- 290 gm, GA 32 +/- 2.2 wks, Postnatal age 7.7 +/- 3.8 days) with significant PDA who were given one dose of indomethacin (0.3 mg/kg intravenously). There was a significant decrease in urinary output, osmolal and free water clearance after therapy. The fractional excretion of sodium, chloride, potassium, glomerular filtration rate and urinary prostaglandin E2 also decreased but were not statistically different from the baseline values. In infants who responded to indomethacin with ductus closure, their renal functions appeared to be preserved even though they had higher plasma indomethacin levels than the non-responders in whom significant changes in renal function were observed following indomethacin therapy. This observation suggested that the improved renal hemodynamics following the closure of the ductus may minimize or attenuate the renal side effects of indomethacin.

Effects of pregnancy and progesterone on autonomic function in the rat urinary bladder

Previous studies have shown that pregnancy is associated with a decrease in cholinergic function in the rabbit urinary bladder. The present study aimed at evaluating the effects of pregnancy on the autonomic function of the rat urinary bladder and to elucidate whether progesterone is responsible for such alterations. Female Wistar rats, 3 months old, were divided into four groups: (1) 2-week pregnant rats; (2) rats given daily intramuscular injections of progesterone 5 mg/kg for 2 weeks; (3) rats given intramuscular injections of vehicle for 2 weeks, and (4) controls. Cystometry showed a significant increase in bladder capacity in the pregnant rats. The wet weight of the pregnant rat bladder was also significantly increased. Histologic study revealed increased bladder wall thickness with interstitial edema and urothelium proliferative changes to a papillary configuration in these pregnant bladders. Bladder muscle strip study showed significantly reduced maximum contractile responses to acetylcholine and methoxamine in the pregnant and the progesterone groups. Muscarinic receptor binding study demonstrated reduced Bmax in the pregnant rats and rats receiving progesterone injections (control group Bmax = 57 +/- 11, pregnant group Bmax = 44 +/- 8, p < 0.05; progesterone group Bmax = 40 +/- 7, vehicle group Bmax = 58 +/- 9 fmol/mg protein, p < 0.05). The contractile response to lower concentrations (10(-6) mol/l to 10(-4) mol/l) of ATP was elevated in the pregnant rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Selective suppression of type B monoamine oxidase immunoreactivity in the raphe nuclei following MPTP administration in the cat

Using immunohistochemistry, we investigated in the cat the effects of MPTP, a Parkinsonian syndrome-inducing substance, on brain type B monoamine oxidase (MAO-B) which is responsible for the conversion of MPTP to its neurotoxic product (MPP+). Intraperitoneal administration of MPTP (5 mg kg-1 daily for 5 days) caused a selective suppression of MAO-B in neurones of the raphe nuclei without affecting hypothalamic MAO-B. Since these effects were accompanied by loss of nigral dopaminergic cells but not of raphe cell bodies or 5-HT immunoreactivity, we suggest that MPTP suppresses raphe MAO-B without destroying its presumed host serotoninergic neurones and that raphe MAO-B does not appear to be crucial in the MPTP-induced nigral lesion. In addition, the MPTP-induced paradoxical sleep suppression might be related to this raphe MAO-B loss.

Use of the urine-to-blood carbon dioxide tension gradient as a measurement of impaired distal tubular hydrogen ion secretion among neonates

To evaluate the utility of the urinary-minus-blood partial pressure of carbon dioxide (U-B PCO2) gradient for the diagnosis of distal renal tubular acidosis in neonates, we measured the U-B PCO2 gradient corresponding to different urinary bicarbonate concentrations in 40 neonates. The U-B PCO2 gradient in these neonates had a significant linear relationship to the urinary bicarbonate concentration. When the urinary bicarbonate concentration was > 10 mmol/L, in all the neonates the U-B PCO2 could be increased above the 20 mm Hg level. We conclude that it is appropriate to determine the U-B PCO2 gradient as an index of distal urinary acidification and that it is a necessary test for diagnosis of distal renal tubular acidosis in neonates.

The role of transrectal ultrasonography on the palpable and impalpable abnormal prostate

Two hundred and three male patients underwent transrectal ultrasonography (TRUS) examination because of palpable nodule or hard consistency of the prostate. Of these, 56 of 65 (86.2%) digital rectal examination (DRE)-abnormal and 34 of 138 (24.6%) DRE-normal patients received transrectal sonoguided core needle biopsy. Among the DRE-abnormal patients, 18 (32.1%) had prostatic adenocarcinoma by biopsy with 2 additional patients who had initial negative biopsies eventually found to have cancer by transurethral resection of the prostate. In contrast, only 2 (5.9%) of 34 DRE-normal patients had cancers that were both hypoechoic and peripheral zone located. In 13 patients with transitional zone located lesions (hypoechoic 9, isoechoic 4), none had cancer. Of 27 patients who had normal DRE and unsuspected TRUS and received transurethral prostatectomy because of bladder outlet obstruction, 4 (14.8%) had cancer. In this study, hypoechoic lesions were found in 68 patients, among them 60 (88.2%) underwent biopsy but only 14 (23.3%) had cancer. From the results of this study, we concluded that TRUS can be a useful adjunct of DRE in detecting prostatic malignancy, especially when there has been an abnormal DRE, but its role on a digitally normal prostate requires further evaluation. Serum prostate-specific antigen can be an additional indicator to increase the prostate cancer detection rate.

Artificial convolution neural network techniques and applications for lung nodule detection

We have developed a double-matching method and an artificial visual neural network technique for lung nodule detection. This neural network technique is generally applicable to the recognition of medical image pattern in gray scale imaging. The structure of the artificial neural net is a simplified network structure of human vision. The fundamental operation of the artificial neural network is local two-dimensional convolution rather than full connection with weighted multiplication. Weighting coefficients of the convolution kernels are formed by the neural network through backpropagated training. In addition, we modeled radiologists' reading procedures in order to instruct the artificial neural network to recognize the image patterns predefined and those of interest to experts in radiology. We have tested this method for lung nodule detection. The performance studies have shown the potential use of this technique in a clinical setting. This program first performed an initial nodule search with high sensitivity in detecting round objects using a sphere template double-matching technique. The artificial convolution neural network acted as a final classifier to determine whether the suspected image block contains a lung nodule. The total processing time for the automatic detection of lung nodules using both prescan and convolution neural network evaluation was about 15 seconds in a DEC Alpha workstation.

Correlation of transrectal ultrasonographic findings of the prostate with the occurrence of detrusor instability in patients with benign prostatic hyperplasia

Forty patients with benign prostatic hyperplasia were evaluated with urodynamics and transrectal ultrasonography. Seventeen patients were found to have detrusor instability while the remaining 23 did not. No significant differences were noted during ultrasonography in the estimated prostatic volume, the presumed circle area ratio and the incidence of finding prostatic calcification between these two groups. However, the incidence of detecting intravesical protrusion of the prostate is significantly higher in patients with instability than in patients with stable bladder (53 vs. 13%, p < 0.01). It is therefore postulated that intravesical protrusion may increase afferent impulses from the prostate and alter the stability status of the urinary bladder.