Effect and distribution of intravenously injected 125I-guanylin in rat kidney examined by high-resolution light microscopic radioautography

125I-guanylin was injected intravenously into rats, and their kidney and intestinal tract were processed for light microscopic radioautography using semithin sections to examine the binding sites. Various doses of unlabeled guanylin were also injected to examine the morphological effects of guanylin on the kidney. Dense labeling of silver grains due to 125I-guanylin were observed only in the kidney. In the cortex, silver grains were localized on the luminal side of the proximal tubules at 5-30 min. In the medulla, silver grains appeared at the basal side of the collecting ducts, capillaries and loops of Henle after 5 min. Silver grains then accumulated in the cytoplasm of the collecting ducts after 10 min, and disappeared after 30 min. The cell height of the inner medullary collecting ducts (IMCD) decreased and their luminal spaces increased dose-dependently 5 min after the injection of both labeled and unlabeled guanylin. These structural changes returned to control levels within 30 min. These results indicate a high density localization of guanylin receptors on the luminal surface of proximal tubules in the renal cortex and also rapid excretion of guanylin through the IMCD. The morphological changes of the IMCD suggest a diuretic effect of guanylin.

[1H-MRSI of Alzheimer's disease]

To evaluate neuronal change in the neocortex of the patients with Alzheimer's disease in early stage, proton MRSI study was performed in 13 probable AD patients and 6 healthy volunteers and the change of NAA, a putative neuronal marker, between the temporal cortex and the white matter including basal ganglia was analyzed. Proton MRSI data were measured with 3D-FT-CSI method, using spin echo method with TE = 135 ms. Two directional 16 x 16 phase encodings were applied on the field of 18 x 18 x 1.5 cm3. One voxel size was 1.9 cm3. Out of thirteen probable AD patients, 7 patents, who were considered in early stage, showed low NAA levels in the temporal neocortex without NAA change in the white matter including basal ganglia. Six patients, who were considered in more advanced stage, showed low NAA levels in both regions. NAA decrease in neocortical area is considered to be a good indication of AD in early stage at the examination with proton MRSI.

Neurovascular compression of the rostral ventrolateral medulla related to essential hypertension

The rostral ventrolateral medulla (RVLM) is thought to serve as a final common pathway for the integration of central cardiovascular information and to be important for the mediation of central pressor responses. An association between essential hypertension and neurovascular compression of the RVLM has been reported. To confirm this relationship and to quantitatively measure the distances between the RVLM and the neighboring arteries, we performed magnetic resonance imaging using a high-resolution 512x512 matrix and magnetic resonance angiography in 49 subjects (21 patients with essential hypertension, 10 patients with secondary hypertension, and 18 normotensive subjects). One patient with essential hypertension was excluded from the evaluations because of inadequate assessment due to poor images. Neurovascular compression of the RVLM was observed in 15 of 20 (75%) patients with essential hypertension. In contrast, neurovascular compression was observed in only 1 of 10 (10%) patients with secondary hypertension and only 2 of 18 (11%) normotensive subjects. The rate of observed neurovascular compression in the essential hypertension group was significantly higher than that in the secondary hypertension group and the normotensive group (P<.01 for both). The distances between the RVLM and the nearest arteries in the essential hypertension group were significantly shorter than those in the other groups (P<.05 for all). On the other hand, the distances between the surface of the medulla oblongata and the nearest arteries did not differ among these three groups. These results suggest that neurovascular compression of the RVLM, but not of the other regions of the medulla oblongata, is particularly related to essential hypertension.

Preoperative detection of the composition of atherosclerotic plaque in the carotid artery using ultrasonography and magnetic resonance imaging

Preoperative identification of the components of atherosclerotic plaque was attempted using ultrasonography in five patients and magnetic resonance (MR) imaging in three patients before carotid endarterectomy. The correlation between surgical and histological findings, and preoperative ultrasonography and MR imaging was evaluated. Plaque consisting predominantly of calcification appeared as bright echo on ultrasonography and was tough. Plaque consisting predominantly of hemorrhage was echolucent, appeared as low intensity on T2-weighted MR images and was fragile. Such preoperative assessment of plaque composition using ultrasonography and MR imaging is useful for manipulation of atherosclerotic plaque during carotid endarterectomy.

[Evaluation of cerebral ischemia with metabolic image by using 3D-CSI--comparing with SPECT and PET]

MR spectroscopy(MRS) is a powerful method to evaluate brain metabolism directly and non-invasively. We developed 3D-CSI method as a multi-voxel MRS. It has some advantages or single-voxel MRS; 1) spectra in many voxels can be acquired simultaneously 2) Mapping of metabolites can be acquired 3) A small size voxel can be obtained. It make it possible to evaluate the change of NAA in wide area. In case of cerebral ischemia, we found the tendency that NAA decreases in fatal damage area and is normal in recoverable damage area. Therefore, we suppose that NAA could be a indicator of viability of neuron. It is necessary to coordinate the data from MRI/ MRS and PET/SPECT for analyzing the pathophysiology of cerebral ischemia.

[Incidence of postmicturition dribble in adult males in their twenties through fifties]

A survey was conducted to investigate postmicturition dribble in the general adult male population. A questionnaire was sent to 3,034 clerical workers between 20 and 50 years of age living in urban areas of Hokkaido and Tokyo, and it was returned by 2,839 men (93.5). The incidence of postmicturition dribble in the men in their 20s, 30s, 40s and 50s, was 11.5, 13.2, 19.4 and 26.9%, respectively. The overall incidence was 17.1%. Of those who had experienced postmicturition dribble; 14.0% dribbled almost daily but the degree of postmicturition dribble was limited to spotting or wetting of the underwear in 93.2%. Therefore, 2.3% of all respondents answered that they had experienced postmicturition dribble almost daily. It is concluded that postmicturition dribble is fairly common in adult men.

Transurethral balloon laser thermotherapy for urinary retention in patients with benign prostatic hyperplasia who are at high surgical risk

BACKGROUND

Twelve patients with benign prostatic hyperplasia and urinary retention, who were considered to be poor candidates for prostatectomy, were treated by transurethral balloon laser thermotherapy (TUBAL-T). The mean patient age was 78.9 years (range, 66 to 93 years) and the mean duration of bladder catheterization was 11 weeks (range, 2 to 48 weeks).

METHODS

Irradiation into the prostatic tissue was done through 360 degrees with a neodymium: yttrium aluminum garnet (Nd:YAG) laser balloon placed in the prostatic urethra, with pain relief provided by using local topical anesthesia. The total laser dose was from 45,000 to 123,376 J, with an average of 73,089 J. The irradiation time was from 40 to 54 minutes, with an average of 45.2 minutes.

RESULTS

Spontaneous voiding became possible in all patients at a mean of 2.8 days (range, 1 to 7 days) after irradiation. The mean catheter-free period was 20.5 months (range, 6 to 34 months), with the longest being 34 months. The international prostatic symptom scores, quality-of-life scores, and peak uroflow rates showed substantial improvement after laser thermotherapy. To date, long-term resumption of spontaneous voiding was successfully achieved in 9 of 12 cases (75%).

CONCLUSION

TUBAL-T is safe and effective alternative for treatment of urinary retention in patients with benign prostatic hyperplasia who are considered to be at high surgical risk.

[The background factors influencing loss of sexual intercourse after transurethral resection of the prostate (TUR-P)--A study using the Sapporo Medical University-Questionnaire]

BACKGROUND

Sexual dysfunction after transurethral resection of the prostate (TUR-P) depends on multiple factors including preoperative erectile function itself. Using the Sapporo Medical University-questionnaire, we analyzed background factors contributing to loss of sexual intercourse after the operation.

PATIENTS AND METHODS

We sent the self-administered questionnaires to 1,000 patients who had received TUR-P. Answers to questions were ranked as scores. Multiple regression analysis was used to identify factors significant for loss intercourse after TUR-P.

RESULTS

The response rate was 63.5%. Patient with incomplete answers and those having diseases affecting voiding or sexual function and antiandrogen medication were excluded from the study. Leaving 536 patients for the final analysis. Scores for sexual desire and erectile function in the patients who received TUR-P were lower than those of age-matched healthy males. When we divided the patients according to frequency of sexual intercourse before and after TUR-P, there was distinct differences in age, scores for sensory disturbance, depression, the cooperative value of the sexual partner, sexual desire, erectile function, nocturia, residual sensation and urgency between those maintaining sexual intercourse and those having lost it. Multiple regression analysis using these factors indicated that the scores of erectile function was the most significant determinant for maintaining sexual intercourse after TUR-P in patients aged from 50 to 69 years, followed by the cooperative value of the sexual partner, residual sensation and sensory disturbance. In those 70 old and older, the score for erectile function was the most significant determinant, followed by the cooperative value of sexual partner.

CONCLUSION

Our results suggest that, irrespective of age, the cooperation of the patient's sexual partner as well as erectile function significantly influence the maintenance of sexual intercourse after TUR-P. In addition, voiding condition and psychological status after TUR-P may affect the maintenance of sexual intercourse in patients in their fifties and sixties.

Flow velocity of the cortical vein and its effect on functional brain MRI at 1.5T: preliminary results by cine-MR venography

The purpose of this study is to demonstrate the effect of altering flow velocity of cerebral cortical veins as the source of the signal change observed in functional magnetic resonance imaging (fMRI) of the brain. 10 healthy volunteers were examined after instructions in self-paced hand grasping. Experiments were performed using a 1.5-Tesla whole body MR scanner with a conventional two-dimensional gradient echo sequence (TR/TE/flip angle 400/60/40, first order flow rephased, reduced band width 8 Hz/pixel). Flow velocity measurements were performed for the cortical veins which corresponded to the activated areas depicted on fMRI. Velocity was estimated from the cine-MR venography (cine-MRV) with a tagging technique. Flow phantom studies were performed to delineate the effect of flow velocity differences upon the subtraction images of fMRI. The cine-MRV revealed increased flow velocity of the cortical veins during activation in seven volunteers, with a mean velocity difference of 15 mm/sec. Flow phantom studies suggested that the increased flow velocity may result in changes of the flow signal profile due to oblique flow displacement. Subtraction of the two images with different flow profiles produces flow signal enhancement. Increased flow velocity of the cortical veins during the activation is an important factor which contributes to the signal of fMRI.

Morphological and pharmacological characterization of guinea-pig prostatic smooth muscle cells in vitro

BACKGROUND

Prostatic smooth muscle is thought to play a major role in the pathogenesis of bladder outlet obstruction in patients with benign prostatic hypertrophy. However, the physiology of prostatic smooth muscle cells remains largely unknown, in part due to the lack of a suitable model system. We therefore sought to establish an in vitro culture of guinea pig prostatic smooth muscle cells.

METHODS

Immature guinea pig prostate was treated by enzymatic digestion and the cells obtained were used to initiate the primary culture. After 3 to 4 passages, cultured smooth muscle cells were examined morphologically by immunocytochemistry and electron microscopy. The contractile properties of cultured smooth muscle cells were also examined.

RESULTS

The cultured prostatic cells demonstrated hill and valley morphology, which is a hallmark of smooth muscle cells in vitro, and stained positively for desmin. In addition, electron microscopic examination of ultrastructural morphology revealed myofilaments. Confluent cultures of prostatic smooth muscle cells showed a clear, dose-dependent contractile response to phenylephrine. Furthermore, contraction of the prostatic smooth muscle cells by 10(-6) mol/L phenylephrine was completely inhibited by pretreatment with 10(-6) mol/L terazosin.

CONCLUSIONS

An in vitro culture of prostatic smooth muscle cells was established. This culture is likely to provide a powerful tool for elucidating the physiology and pathophysiology of prostatic smooth muscle.

A monoclonal antibody to astrocytes, subepithelial fibroblasts of small intestinal villi and interstitial cells of the myenteric plexus layer

A monoclonal antibody was developed, using cultured subepithelial fibroblasts of rat duodenal villi as the antigenic material, by in vitro immunization. Hybridomas were selected on cryosections of rat brain and small intestine using indirect immunofluorescence techniques. The monoclonal antibody, termed 8E1, was very useful to label GFAP-positive astrocytes in the adult rat brain, subepithelial fibroblasts of intestinal villi and Thuneberg's fibroblast-like interstitial cells associated with the myenteric plexus layer. These cells are known to be stellate in shape, forming a cellular network with extended cell processes that communicate via gap junctions. Immature astrocytes such as radial fibers were not immunolabeled with mAb-8E1. Immunoelectron microscopy revealed clustered gold labeling of 8E1 antigen on the intermediate filaments of cultured astrocytes and cultured subepithelial fibroblasts. This staining pattern was different from the continuous and linear gold labeling of GFAP and vimentin. MAb-8E1 did not immunoblot purified human brain GFAP nor bovine lens vimentin, and so was not neutralized by preabsorption with these molecules. Immunoblot analysis after SDS-PAGE showed that the antigen recognized by mAb-8E1 was a Mr 50K protein in the rat cerebra, and a Mr 56K protein in the cultured subepithelial fibroblasts. This study showed that astrocytes and some types of stellate cells share distinct antigenic properties in the components of their intermediate filaments.

Evaluation of metabolic heterogeneity in brain tumors using 1H-chemical shift imaging method

Seventeen brain tumors were measured by 1H-CSI (chemical shift imaging) in a 1.5 T clinical magnetic resonance scanner. The metabolic peaks obtained were evaluated by two methods. One method was to obtain the percentage of each metabolite relative to the combined choline, creatine and NAA peak areas, and the other method was to obtain a ratio of the tumor to contralateral brain. The percentage of choline (%Cho) and choline ratio increased, and the %NAA and NAA ratio decreased in the gliomas and malignant tumors. In relation to grading, %Cho increased but the choline ratio did not. We believed the reason for this was that there were many foci of microscopic necrosis in the glioma grade IV. Free lipids were observed in most of the high grade gliomas and in a malignant tumor. Lactate increased in higher grade tumors. Meningiomas showed the highest %Cho. Statistical differences between the grades of glioma were not detected because many tumors had heterogeneous tissue. One resolution to this problem was metabolite mapping. Mapping of the percentage of metabolites was suitable because it described the regional metabolic changes and the resulting signal to noise ratio was better than that achieved by other methods of evaluation.

[The role of magnetic resonance spectroscopic imaging in patients with Parkinson's disease]

There are some single voxel proton magnetic resonance spectroscopy(MRS) of Parkinson's disease but no multi-voxel proton MRS. Proton magnetic resonance spectroscopic imaging(MRSI) is the multi-voxel method, from which we can obtain many spectra from many voxel at the same time. The distribution of each metabolite can be observed in the metabolite map. Although defects in oxidative phosphorylation have been reported from the studies of Parkinson's disease and dopaminergic cell death has been observed, the cause of Parkinson's disease is unknown. The spectra from the striatum and surroundings and the metabolite maps in MRSI will help to understand the pathogenesis of the disease.

Lysosphingomyelin-elicited Ca2+ mobilization from rat brain microsomes

We have examined the Ca2+ release activity of sphingolipid-derivatives from rat brain microsomes using a Fura-2 cytofluorometric assay. Sphingosylphosphorylcholine, lysosphingomyelin, elicited a rapid Ca2+ release from both cerebral and cerebellar microsomes. Other compounds including sphingosine and sphingosine-1-phosphate were incapable of causing the Ca2+ release. The pharmacological properties suggest that the sphingosylphosphorylcholine-elicited Ca2+ mobilization is not mediated by inositol 1,4,5-triphosphate receptors. Immunocytochemical study showed the occurrence of sphingomyelin, a putative precursor for sphingosylphosphorylcholine, in the somatodendritic membrane domains of cerebellar neurons. These observations imply that sphingosylphosphorylcholine is a potent Ca2+ releaser in brain neurons.

Restricted occurrence of an unusual ganglioside GD1 alpha in rat brain and its possible involvement in dendritic growth of cerebellar Purkinje neurons

The spatial pattern of expression of a minor disialosyl ganglioside GD1 alpha in the rat brain was investigated immunohistochemically using a specific murine monoclonal antibody KA-17. The antibody shows noticeable immunoreactivity in the proximal dendrites and neuronal cell bodies of restricted populations of neurons including cerebral pyramidal neurons and cerebellar Purkinje neurons. Immunocytochemical analysis revealed that Purkinje neurons maintained in a dissociate culture condition also express GD1 alpha in the dendrites and cell bodies. We have examined the functional involvement of this ganglioside in the growth of brain neurons using KA-17 antibody. Addition of the antibody to cerebellar primary cultures caused perturbation of the dendritic development of Purkinje neurons in a dose-dependent manner. The length and branching of the dendrites were severely decreased by the antibody treatment. When other anti-glycoconjugate or sphingolipid monoclonal antibodies were tested, only HNK-1 monoclonal antibody that recognizes sulfoglucuronic residues in glycolipids and glycoproteins had similar but moderate inhibitory actions on the dendritic development of these neurons. In contrast to the morphological alterations observed in Purkinje cells, other cerebellar cells including granule neurons appear to be almost normal following the antibody treatment. These observations lead to the possibility that GD1 alpha ganglioside has a role in the development of Purkinje cell dendrites.

Irradiation effects on the metabolism of metastatic brain tumors: analysis by positron emission tomography and 1H-magnetic resonance spectroscopy

To evaluate irradiation effects on the metabolism of metastatic brain tumors treated by Gamma Knife radiosurgery, positron emission tomography (PET) and 1H-magnetic resonance spectroscopy (MRS) studies were performed on five patients. The tumor origins were lung cancer in three patients and breast cancer in two. Treatment volume was 0.4-10.1 cm3 (mean: 5.5 cm3). The marginal dose to the tumor was 24-30 Gy (mean: 26.2 Gy). The follow-up period was 5-19 months (mean: 13.4 months). No patients had conventional whole-brain radiation therapy. 18F-fluoroboronophenylalanine (18FBPA) or 18F-fluorodeoxyglucose (18FDG) were used as tracers for the PET study. Using 1H-MRS, several metabolites were simultaneously measured in metastatic brain tumor and adjacent brain. In the PET study of the representative case, the uptake rate of 18FBPA that is actively transported to the tumor decreased markedly 15 days after radiosurgery and continued to decrease thereafter. In the 1H-MRS study, choline, which is characteristically high in metastatic brain tumors, also decreased over time. In two cases with suspected radiation injury, the enhanced region, which was decreased in size in early follow-up, enlarged progressively and was accompanied by edema. However, 18FBPA and 18FDG were not transported to the enhanced region. The peak of free lipid, which might show destruction of the cell membrane, was recognized in the enhanced region and adjacent brain in these cases. This study revealed that radiation effects on the metabolism of metastatic brain tumors occur at an early stage after radiosurgery and continue over several months. In particular, in the case of radiation injury, PET and 1H-MRS studies made it possible to distinguish between regrowth of the tumor and radiation injury.

Sphingolipid biosynthesis is necessary for dendrite growth and survival of cerebellar Purkinje cells in culture

The requirement of complex sphingolipid biosynthesis for growth of neurons was examined in developing rat cerebellar Purkinje neurons using a dissociated culture system. Purkinje cells developed well-differentiated dendrites and axons after 2 weeks in a serum-free nutrient condition. Addition of 2 microM fumonisin B1, a fungal inhibitor of mammalian ceramide synthase, inhibited incorporation of [3H]galactose/glucosamine and [14C]-serine into complex sphingolipids of cultured cerebellar neurons. Under this condition, the expression of Purkinje cell-enriched sphingolipids, including GD1 alpha, 9-O-acetylated LD1 and GD3, and sphingomyelin, was significantly decreased. After 2 weeks' exposure to fumonisin B1, dose-dependent measurable decreases in the survival and visually discernible differences in the morphology were seen in fumonisin-treated Purkinje cells. The Purkinje cell dendrites exhibited two types of anomalies; one population of cells developed elongated but less-branched dendrites after a slight time lag, but their branches began to degenerate. In some cells, formation of elongated dendrite trees was severely impaired. However, treatment with fumonisin B1 also led to the formation of spinelike protrusions on the dendrites of Purkinje cells as in control cultures. In contrast to the alterations observed in Purkinje cells, morphology of other cell types including granule neurons appeared to be almost normal after treatment with fumonisin B1. These observations indicated strongly that membrane sphingolipids participate in growth and maintenance of dendrites and in the survival of cerebellar Purkinje cells. Indeed, these effects of fumonisin B1 were reversed, but not completely, by the addition of 6-[[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino dcaproyl]sphingosine (C6-NBD-ceramide), a synthetic derivative of ceramide. Thus, we conclude that deprivation of membrane sphingolipids in a culture environment is responsible for aberrant growth of Purkinje cells.

Ultrasonographic and pathologic changes in the prostate of patients with benign prostatic hyperplasia after transurethral balloon laser therapy

Twenty-seven patients with benign prostatic hyperplasia (BPH) were treated with a transurethral flexible laser balloon (PROSTALASE) under ultrasound guidance. Three months after treatment, 22 (82%) of the patients showed a 50% or greater decrease in the AUA Symptom Score. The average uroflow rate, peak uroflow rate, and postvoiding residual urine volume also showed significant improvement. Ultrasonography showed that the prostatic volume had decreased by 17% (8%-37%). Also, a circular hyperechoic zone about 3 cm in diameter was noted around the prostatic urethra. The prostatic tissue in the hyperechoic zone was sampled by transperineal needle biopsy under transrectal ultrasound guidance, and histopathologic examination showed degenerative necrosis. The necrotic tissue was gradually absorbed, resulting in prostatic shrinkage at around the third month. These results suggest that clinical improvement, both subjective and objective, is brought about by this therapy.

Neuronal expression of a minor monosialosyl ganglioside GM1b in rat brain: immunochemical characterization using a specific monoclonal antibody

Monoclonal antibodies (mAbs) against GM1b ganglioside were raised by immunizing NZB/n mice with the antigen purified from bovine brains, and the details of binding specificity of the mAbs were characterized. Anti-GM1b mAb, termed NA-6, reacted specifically with GM1b (NeuAc) and GM1b(NeuGc). NA-6 antibody did not react with other structurally related gangliosides, indicating that the antibody recognizes NeuAc or NeuGc alpha 2-3Gal beta 1-4GalNAc beta 1-4Gal structure. Using NA-6 antibody, GM1b ganglioside in developing rat brain was investigated by TLC/enzyme-immunostaining and detected first on gestational day 16. The specific content of brain GM1b increased until postnatal day 10, and then gradually decreased in later stage of development. Immunohistochemically GM1b was found in proximal dendrites and cell bodies of neurons in extensive regions of adult rat brain. The immunoreactivity tended to be confined in patch-like clusters on cell membranes, as typically found in the hippocampus and neocortex. The GM1b synthase activity, when assayed in the cerebellar microsome proteins, was significantly reduced in lurcher mutant mouse that is devoid of both cerebellar granule and Purkinje cells. These findings demonstrate that GM1b ganglioside exists in neurons and is actively synthesized during the development in rat brain.

Cerebral MRI and spectroscopy in Sjögren-Larsson syndrome: case report

We report MRI and MRS of the brain in a patient with Sjögren-Larsson syndrome (SLS) in whom fatty alcohol oxidoreductase (FAO) deficiency has been verified. MRI showed periventricular lesions, high intensity on T2-weighted and low intensity on T1-weighted images at trigones of the lateral ventricles. 1H-MRS of these lesions revealed high lipid and low N-acetyl aspartate peaks. We presume such lipids in periventricular lesions with high T2 signal may be pathognomonic of SLS.

Transurethral balloon laser thermotherapy for symptomatic benign prostatic hyperplasia: preliminary clinical results

Between April 1993 and May 1994, 66 patients were treated with transurethral balloon laser thermotherapy (TUBAL-T) for the relief of bladder outlet obstruction secondary to benign prostatic hyperplasia. TUBAL-T, with a urethral cooling system, employs a balloon catheter and irradiating laser through 360 degrees to produce deep coagulation and necrosis of the prostatic tissue while preserving the urethral mucosa. The procedure was implemented under local topical anesthesia. Baseline AUA Symptom Scores, peak uroflow rates, postvoiding residual urine volumes (PVR), and prostatic volumes were measured before and at 1, 3, 6, and 12 months after treatment. The mean symptom score decreased from 18.8 preoperatively to 9.8, 6.9, 7.4, and 4.8 at 1, 3, 6, and 12 months, respectively. The mean peak uroflow rate increased from 6.4 mL/sec to 9.1, 11.2, 10.1, and 10.4 mL/sec at 1, 3, 6, and 12 months, respectively. As for the mean PVR, statistically significant reductions were clearly observed at 3 and 6 months after treatment. However, at 1 and 12 months, the difference was not statistically significant. In follow-up for as long as 12 months after the procedure, 23 of 26 patients (88%) showed an improvement of 50% or more in the AUA Symptom Scores. Of 20 available patients, 12 (60%) showed an improvement of 50% or higher in the peak uroflow rates, and 10 (50%) showed an improvement of 50% or higher in PVR. The mean prostatic volume reductions at 3, 6, and 9 months were 12%, 16%, and 14%, respectively. The serum prostate specific antigen concentration increased to four times the baseline concentration on the 7th day.(ABSTRACT TRUNCATED AT 250 WORDS)

Granule swelling in stimulated bovine adrenal chromaffin cells: regulation by internal granule pH

Adrenal medullary chromaffin cells secrete catecholamines through exocytosis of their intracellular chromaffin granules. Osmotic granule swelling has been implicated to play a role in the generation of membrane stress associated with the fusion of the granule membrane. However, controversy exists as to whether swelling occurs before or after the actual fusion event. Using morphometric methods we have determined the granule diameter distributions in rapidly frozen, freeze-substituted chromaffin cells. Our measurements show that intracellular chromaffin granules increase in size from an average of 234 nm to 274 nm or 277 nm in cells stimulated to secrete with nicotine or high external K+, respectively. Granule swelling occurs before the formation of membrane contact. Ammonium chloride, an agent which inhibits stimulated catecholamine secretion by approximately 50% by altering the intragranular pH, also inhibits granule swelling. In addition, ammonium chloride-treated secreting cells show more granule-plasma membrane contacts than untreated secreting cells. Sodium propionate induces granule swelling in the absence of secretagogue and has been shown to enhance nicotine- and high K(+)- induced catecholamine release. These results indicate that in adrenal chromaffin cells granule swelling is an essential step in exocytosis before fusion pore formation, and is related to the pH of the granule environment.

Overexpression of choline acetyltransferase reconstitutes discrete acetylcholine release in some but not all synapse formation-defective neuroblastoma cells

Secretion of acetylcholine (ACh) in neuroblastoma cells overexpressing choline acetyltransferase (ChAT) was examined. With transient transfection of ChAT cDNA, neuroblastoma cells, which have no endogenous ChAT and either adhere to myotubes or not, failed to form functional synapses, and thus no evidence for release of ACh was detected. Stable neuroblastoma cell lines overexpressing ChAT accumulated ACh inside the cell, and slowly released ACh to the outside of the cell in a calcium-independent fashion. However, after co-culturing them with rat muscle cells, these transformed cells adhered to myotubes and ACh was secreted in a discrete fashion into the synaptic cleft efficiently in some neuroblastoma cell lines but rather inefficiently in another cell line. The results show that the latent secretion machinery of ChAT overexpressing neuroblastoma cells either is competent or possess defect(s) in ACh release.