Implementation and mixed-methods evaluation of "Walk with a Doc" program at Stony Brook

CONTEXT

Walking groups run by trained individuals, lasting under an hour in a natural environment, may be a cost-effective way by which to encourage sustainable changes in physical activity as well as foster companionship and a shared experience of wellness among participants. Walk with a Doc (WWaD) is a national program that provides a platform for medical professionals, including physicians and medical students, to deliver a short talk on a health topic prior to walking side by side with patients and community members.

OBJECTIVES

To evaluate the WWaD Chapter at Stony Brook following implementation, a questionnaire was designed utilizing a mixed-methods approach (i.e., containing qualitative and quantitative items) and administered to all attendees monthly prior to the health discussion. The aim of the questionnaire was fourfold: first, to obtain participant demographics; second, to obtain information on attendees' own perceptions of their health status and the role exercise plays in their health; third, to gain data on physical activity levels, including lengths of exercise sessions and types of activities performed; and fourth, to learn more about attendees' motivations and goals for participating in the walks.

METHODS

We received an IRB exemption. Physician and medical student volunteers were recruited from Stony Brook University Hospital, a suburban tertiary care center, to oversee program logistics. WWaD was scheduled to take place on the third Sunday of every month for 1 h at Heritage Park in Mount Sinai, New York. The event was advertised by volunteers to colleagues, peers, patients, and community members utilizing word of mouth, printed flyers, emails to listservs, and social media outlets. Each month, a physician volunteer oversaw a brief discussion (approximately 10 min in length).

RESULTS

Over the course of the 5 month evaluation period, 91 individuals participated in the walks, including repeat attendees. After excluding duplicate or incomplete entries, data from 30 participants were included in this analysis. The majority of participants were female (n=24) with a mean age of 50 years (range, 23-98 years). Feedback on WWaD program elements was largely positive. Participants commended the monthly speakers for "informative talks" (n=6) on "interesting topics" (n=4), with plans to review the supplemental information in educational pamphlets following the walk (n=4). The brochures were also deemed "helpful." Overwhelmingly, patients referred to the community gathering and team building aspects of WWaD as the "most enjoyable" aspect of the program (n=8) and a key driver for participation.

CONCLUSIONS

This mixed-methods study of the WWaD chapter at Stony Brook contributes to a growing body of evidence highlighting the value of walking groups as effective avenues for collaboration in producing accessible healthy behavior.

Trends in Ethnicity, Race, and Sex Among Psychiatry and Non-psychiatry Residency Applicants, 2008-2019

OBJECTIVE

The objective of this study was to examine trends in racial/ethnic and gender representation among US psychiatry residency applicants compared with non-psychiatry applicants.

METHODS

Using publicly available applicant data, racial/ethnic and gender distributions of psychiatry residency applicants from 2008 to 2019 were examined and compared with non-psychiatry residency applicants. Both longitudinal trends within both cohorts and cross-sectional, between-group differences were examined.

RESULTS

From 2008 to 2019, the percentage of female, American Indian/Alaskan Native (AIAN), Black, Hispanic, and Native Hawaiian/Other Pacific Islander (NHPI) psychiatry and non-psychiatry residency applicants increased (p<.001). Within each year, Black and Asian applicants comprised a larger percentage of psychiatry applicants compared with non-psychiatry applicants (p<.001). Between 2008 and 2019, Black psychiatry and non-psychiatry applicants increased from 9.1% to 11.6% and 6.6% to 7.6%, respectively; Asian psychiatry and non-psychiatry applicants decreased from 39.5% to 30.5% and 27.5% to 26.6%, respectively; White psychiatry and non-psychiatry applicants increased from 26.7% to 38.2% and 42.7% to 49.2%, respectively.

CONCLUSIONS

Racial/ethnic and gender characteristics of US psychiatry residency applicants represent the future of the US psychiatric workforce. The US psychiatry residency applicant pool has become increasingly diverse from 2008 to 2019. Initiatives should work to enhance representation of psychiatry applicants from historically marginalized backgrounds, and simultaneously to recruit and retain a diverse psychiatric workforce following residency training.

Antiemetic Prophylaxis and Anesthetic Approaches to Reduce Postoperative Nausea and Vomiting in Bariatric Surgery Patients: a Systematic Review

While guidelines exist for the management of postoperative nausea and vomiting (PONV) in the general surgical setting, there are no established guidelines for the prevention or treatment of PONV in bariatric patients, in whom PONV contributes significantly to perioperative morbidity and hospital resource utilization. This systematic review found that the multimodal pharmacological approach to PONV prevention recommended in current guidelines for high-risk surgical patients is appropriate for the bariatric subset. This includes multi-agent antiemetic prophylaxis with dexamethasone and one or more agents from other classes, and opioid-free total intravenous anesthesia, though the advantages of the latter need further evaluation. There remains a need for a standardized validated instrument to assess PONV in the bariatric setting.

Use of Low-Frequency Driver Mutations Detected by Cell-Free Circulating Tumor DNA to Guide Targeted Therapy in Non–Small-Cell Lung Cancer: A Multicenter Case Series

Purpose

To evaluate the clinical outcome of patients with non–small-cell lung cancer treated by targeting low variant allelic frequency (VAF) driver mutations identified through cell-free DNA (cfDNA) next-generation sequencing (NGS). Detection of driver mutations in cancer is critically important in the age of targeted therapy, where both tumor-based as well as cfDNA sequencing methods have been used for therapeutic decision making. We hypothesized that VAF should not be predictive of response and that low VAF alterations detected by cfDNA NGS can respond to targeted therapy.

Patients and Methods

A multicenter retrospective case review was performed to identify patients with non–small-cell lung cancer who received targeted molecular therapy on the basis of findings of low VAF alterations in cfDNA NGS. Mutations at low VAF were defined as < 0.2% mutated cfDNA molecules in a background of wild-type cfDNA.

Results

One hundred seventy-two patients underwent cfDNA NGS testing. Of the 172 patients, 12 were identified as having low VAF driver alterations and were considered for targeted therapy. The median progression-free survival (PFS) for all patients was 52 weeks (range, 17 to 88 weeks). For patients with EGFR exon 19 deletion (n = 7), the median PFS was 52 weeks (range, 17 to 60.5 weeks). For patients with EML4-ALK fusions (n = 3), the median PFS was 60 weeks (range, 18 to 88 weeks). The median overall survival for all patients after diagnosis was 57.6 weeks.

Conclusion

Targeted treatment response for driver mutations detected by cfDNA may be independent of VAF, even in relation to other higher VAF aberrations in plasma, and directly dependent on the underlying disease biology and ability to treat the patient with appropriate targeted therapy.

Genomic Landscape of Appendiceal Neoplasms

Purpose

Appendiceal neoplasms are heterogeneous and are often treated with chemotherapy similarly to colorectal cancer (CRC). Genomic profiling was performed on 703 appendiceal cancer specimens to compare the mutation profiles of appendiceal subtypes to CRC and other cancers, with the ultimate aim to identify potential biomarkers and novel therapeutic targets.

Methods

Tumor specimens were submitted to a Clinical Laboratory Improvement Amendments-certified laboratory (Foundation Medicine, Cambridge, MA) for hybrid-capture-based sequencing of 3,769 exons from 315 cancer-related genes and 47 introns of 28 genes commonly rearranged in cancer. Interactions between genotype, histologic subtype, treatment, and overall survival (OS) were analyzed in a clinically annotated subset of 76 cases.

Results

There were five major histopathologic subtypes: mucinous adenocarcinomas (46%), adenocarcinomas (30%), goblet cell carcinoids (12%), pseudomyxoma peritonei (7.7%), and signet ring cell carcinomas (5.2%). KRAS (35% to 81%) and GNAS (8% to 72%) were the most frequent alterations in epithelial cancers; APC and TP53 mutations were significantly less frequent in appendiceal cancers relative to CRC. Low-grade and high-grade tumors were enriched for GNAS and TP53 mutations, respectively (both χ² P < .001). GNAS and TP53 were mutually exclusive (Bonferroni corrected P < .001). Tumor grade and TP53 mutation status independently predicted OS. The mutation status of GNAS and TP53 strongly predicted OS (median, 37.1 months for TP53 mutant v 75.8 GNAS-TP53 wild type v 115.5 GNAS mutant; log-rank P = .0031) and performed as well as grade in risk stratifying patients.

Conclusion

Epithelial appendiceal cancers and goblet cell carcinoids show differences in KRAS and GNAS mutation frequencies and have mutation profiles distinct from CRC. This study highlights the benefit of performing molecular profiling on rare tumors to identify prognostic and predictive biomarkers and new therapeutic targets.

The effects of reserpine and hypoxia on the amine-storing granules of the hamster carotid body

The carotid bodies from control, reserpine-treated, and hypoxia-treated hamsters were fixed with phosphate-buffered glutaraldehyde and osmium tetroxide, s-Collidine-buffered osmium tetroxide, or phosphate-buffered glutaraldehyde followed by potassium dichromate incubation. Following glutaraldehyde-osmium tetroxide fixation no differences in density or population of the electron-opaque granules in the glomus cells of either control or experimental animals were observed. With s-Collidine-buffered osmium tetroxide and the glutaraldehyde-dichromate technique a marked decrease in density without an appreciable reduction in number of granules was noted after reserpine treatment, while in hypoxia-treated hamsters the density and population of the granules were not different from those of the controls. The results indicate that reserpine depletes the amines without granule disappearance and that hypoxia does not affect the amine content of the granules. It is suggested that following glutaraldehyde-osmium tetroxide double fixation, persistence of the density of the granules in reserpine-treated animals is due primarily to the nonamine content, and that the amines in the glomus cells are probably not directly involved in the respiratory reflex.

Hepatitis C virus infection among teenagers in an endemic township in Taiwan: epidemiological and clinical follow-up studies

The aim of the study was to elucidate the epidemiological features of Hepatitis C virus (HCV) infection among teenagers in an endemic area by conducting a mass screening study. We also investigated the clinical outcome of the anti-HCV-positive subjects by conducting subsequent short-term and long-term follow-up studies. All 2837 students of two junior middle schools in Tzukuan, aged 13-16 years, were invited to be screened for anti-HCV, HBsAg, AST and ALT in October 1995. A total of 2726 (96%) students responded. Anti-HCV, HCV RNA and aminotransferase levels were evaluated among anti-HCV-positive students 1 month and 30 months later, respectively. A total of 38 (1.4%; M/F = 22/16) participants were anti-HCV-positive. The anti-HCV-positive students had higher rates of exposures to transfusion, anti-HCV-positive families and surgery. The prevalence (2.8%) of the 7 maritime villages was markedly higher than that (0.7%) of the other 8 villages (P < 0.001). Subsequent follow-up studies demonstrated that there might be 5 cases of acute or recent HCV infection, and 6 cases who had recovered from chronic HCV infection.

Systemic administration of a water-soluble hexasulfonated C(60) (FC(4)S) reduces cerebral ischemia-induced infarct volume in gerbils

Buckminsterfullerence and its derivatives have recently been shown to exhibit considerable in vivo biological activities. A water-soluble hexasulfonated C(60) (FC(4)S) has been shown to protect against oxidative stress. Neuroprotective effects of FC(4)S were investigated in the present study. Focal cerebral ischemia was produced by a permanent occlusion of the right middle cerebral artery in gerbils. Infarct volumes were determined by 2,3,5-triphenyltetrazolium chloride transcardiac perfusion 24 h after cerebral ischemia. Chronic pretreatment of FC(4)S (0.5 and 5.0 mg/kg/day, intraperitoneally for 2 weeks) significantly reduced the infarct volume (by 42% and 68%, respectively) when compared to that of the control group. Results revealed that chronic pretreatment of FC(4)S may protect the brain against focal cerebral ischemia.

A new method for true and spurious eigensolutions of arbitrary cavities using the combined Helmholtz exterior integral equation formulation method

Integral equation methods have been widely used to solve interior eigenproblems and exterior acoustic problems (radiation and scattering). It was recently found that the real-part boundary element method (BEM) for the interior problem results in spurious eigensolutions if the singular (UT) or the hypersingular (LM) equation is used alone. The real-part BEM results in spurious solutions for interior problems in a similar way that the singular integral equation (UT method) results in fictitious solutions for the exterior problem. To solve this problem, a Combined Helmholtz Exterior integral Equation Formulation method (CHEEF) is proposed. Based on the CHEEF method, the spurious solutions can be filtered out if additional constraints from the exterior points are chosen carefully. Finally, two examples for the eigensolutions of circular and rectangular cavities are considered. The optimum numbers and proper positions for selecting the points in the exterior domain are analytically studied. Also, numerical experiments were designed to verify the analytical results. It is worth pointing out that the nodal line of radiation mode of a circle can be rotated due to symmetry, while the nodal line of the rectangular is on a fixed position.

Satellite videoconferencing for healthcare workers: audience characteristics and the importance of continuing education credits

To assess the opinions of healthcare workers (HCWs) about a satellite videoconference as a means of earning continuing education credit, a telephone survey was conducted in September 1998, 1 month after a live interactive satellite videoconference on antimicrobial use and resistance. There were 180 registered sites in 45 states surveyed, representing 1,589 viewers: 764 nurses (48.1%), 201 physicians (12.6%), and 624 other HCWs (39.3%). Continuing education credit was requested by 51% of nurses, 31% of physicians, and 27% of all other HCWs. Although preferred learning formats varied, 70% of respondents said it was important to offer continuing education credit. Furthermore, 31% of the respondents stated that the videoconference influenced institutional strategies. We concluded that satellite videoconferences are a method to reach audiences around the world efficiently and effectively, provide the latest information, facilitate interaction, and meet some of the demand for continuing education credit for HCWs.

Endothelial cell regrowth and morphology after balloon catheter injury of alloxan-induced diabetic rabbits

Neointimal thickening after catheter injury has been reported to be influenced by the integrity of the vascular endothelium. We have previously shown that neointimal thickening is significantly reduced in alloxan-induced diabetic New Zealand White rabbits after catheter injury compared with euglycemic rabbits. In the present study, it was hypothesized that endothelial cell regrowth, morphology, and endothelium-dependent vasoreactivity after catheter injury are improved in the diabetic rabbit (glucose >/=400 mg/dl) compared with the euglycemic rabbit. Two weeks after catheter injury, the percent endothelial regrowth was significantly increased in diabetic animals compared with euglycemic animals (32.1 +/- 2 and 15.6 +/- 1, respectively; P < 0.05). The endothelial cell morphology analyzed by scanning electron microscopy was also restored 2 wk after catheter injury in thoracic aortas from the diabetic animals compared with vessels from euglycemic animals. Endothelium-dependent relaxation to ACh in vessels from diabetic and euglycemic rabbits was attenuated 2 wk after injury, and, although improved by 4 and 8 wk, relaxation remained significantly depressed. These results suggest that endothelial cell regrowth and morphology in diabetic animals was improved compared with euglycemic animals; however, endothelium-dependent vasoreactivity remained impaired. Thus the attenuated neointimal thickening seen in the diabetic rabbit may be a function of the rate and degree of regrowth rather than the normalization of ACh-induced relaxation.

Ex vivo expression of nitric oxide synthase isoforms (eNOS/iNOS) and calmodulin in human penile cavernosal cells

PURPOSE

Nitric oxide (NO) synthesized by nitric oxide synthase (NOS) is recognized as the central mediator of penile erection. This process appears to be mediated mainly by neuronal NOS (nNOS), which is localized to the nonadrenergic, noncholinergic innervation of the penis. However, the role of non-neuronal penile constituents (specifically the cavernosal smooth muscle), as well as other NOS isoforms in NO production in the human penis is not well understood. The present study evaluates the expression of non-neuronal (inducible and endothelial) isoforms of NOS in human penile cavernosal smooth muscle cells in culture.

MATERIALS AND METHODS

Primary culture was initiated with explants of human corpora cavernosa. For gene expression studies, total RNA was extracted from cavernosal cells and subjected to reverse transcriptase polymerase chain reaction (RT-PCR). For NADPH-diaphorase histochemistry, the cells were incubated with 1 mM beta-NADPH and 0.5 mM nitrobluetetrazolium at 37C for 3 hours. For indirect immunofluorescence and electron microscopy, cells were incubated overnight at 4C with specific primary (eNOS; calmodulin) and secondary antibodies. A conventional avidin biotin complex technique was used for electron microscopy.

RESULTS

The mRNA expression studies revealed that these cells express both endothelial (eNOS) and inducible (iNOS) forms. Localization studies showed positive signals for NADPH-diaphorase, eNOS, and calmodulin. The electron microscopic evaluation confirmed the localization of eNOS to the cytoplasm and small vesicles in the cells.

CONCLUSIONS

These findings support the hypothesis that human cavernosal smooth muscle cells express both endothelial and inducible forms of NOS, which may significantly contribute to NO production in the penile architecture during the erectile process.

Mediation of gamma-hexachlorocyclohexane-induced DNA fragmentation in HL-60 cells through intracellular Ca2+ release pathway

The cytotoxicity of gamma-hexachlorcyclohexane (gamma-HCC) was evaluated in HL-60 cells. Gamma-HCC dose-dependently induced cytotoxicity of HL-60 with an IC50 value of 60+/-5 microM. The gamma-HCC treated cells showed some characteristic changes of apoptosis, including blebbing of the membrane, condensation of the nuclear chromatin, vacuolation of cytoplasm and internucleosomal DNA fragmentation. Gamma-HCC induced DNA fragmentation of HL-60 cells in a dose-, time- and Ca2+-dependent manner. The DNA fragmentation induced was inhibited by intracellular Ca2+ chelator, calmodulin antagonist and Ca2+ sensitive endonuclease inhibitor. Gamma-HCC caused a steady increase in the cytosolic free Ca+ concentration due to release from intracellular stores. Neither the DNA fragmentation nor the increase of intracellular Ca2+ induced by gamma-HCC was inhibited by the removal of extracellular Ca2+. These data suggested that the cytotoxicity of gamma-HCC in HL-60 cells is mediated by the increase of intracellular Ca2+ concentration and the activation of Ca2+-dependent endonuclease, which triggers apoptosis in a Ca2+ and calmodulin-dependent manner.

Comparative studies on the induction of muscle contracture in mouse diaphragm and Ca2+ release from sarcoplasmic reticulum vesicles by organotin compounds

Effects of organotins, including triethyltin and tributyltin, on skeletal muscle were studied with diaphragm and isolated sarcoplasmic reticulum membrane vesicles. Triethyltin induced muscle contracture in mouse diaphragm while tributyltin had comparatively less potency and efficacy in inducing the muscle contracture. The contracture induced by tributyltin was inhibited when the diaphragm was pretreated with low Ca2+ medium or caffeine while the contracture induced by triethyltin persisted in the Ca2+-free medium but was inhibited by pretreatment of caffeine. Pretreatment of dithiothreitol blocked the contracture induced by tributyltin but not that by triethyltin. Triethyltin dose-dependently induced Ca2+ release from sarcoplasmic reticulum vesicles and inhibited the Ca2+-ATPase activity. These results suggested that triethyltin induced contracture in mouse diaphragm was mainly by induction of Ca2+ release and inhibition of Ca2+ uptake of the internal Ca2+ storage site the sarcoplasmic reticulum, while the tributyltin induced contracture might be due to enhancement of extracellular Ca2+ influx which further induce the release of internal Ca2+ through the Ca2+-induced Ca2+ release mechanism.

Effect of short-term treatment with a monoclonal antibody to P-selectin on balloon catheter-induced: intimal hyperplasia, re-endothelialization, and attenuation of endothelial-dependent relaxation

The effects of an anti-P-selectin monoclonal antibody (MAb, PB1.3; Cytel Corporation) on neoendothelialization; neoendothelial function, as evidenced by acetylcholine-induced relaxation (nitric oxide formation); and intimal hyperplasia following embolectomy catheter-induced injury to the rabbit thoracic aorta were investigated. Catheter injury was induced in two groups of New Zealand White rabbits. One group received no treatment, while the second group received short-term treatment with the MAb (i.p., immediately before and 12 h after induction of catheter injury). A third group underwent a sham operation and served as uninjured controls. Following sacrifice at 2 weeks after injury, aortic rings were assessed for degree of intimal hyperplasia, neoendothelial morphology (scanning electron microscopy), and acetylcholine-induced relaxation. Aortic tissue from catheter-injured animals that received treatment exhibited improved neoendothelial morphology, as compared with tissue from untreated but catheterized animals; however, no statistically significant attenuation of the hyperplastic response or improvement in the attenuated neoendothelial-dependent acetylcholine-induced relaxant response that is characteristic of neoendothelium that forms after catheter denudation was observed. These data suggest that short-term attenuation of P-selectin-mediated polymorphonuclear leukocyte (PMN)/endothelium, PMN/platelet interactions, and/or thrombin formation beneficially affects neoendothelialization of the vascular wall following balloon catheter-induced injury.

Incidence of hepatitis C infection in a hepatitis C endemic township in southern Taiwan

To realize the incidence of hepatitis C virus (HCV) infection in an HCV endemic township, Tzukuan, in Taiwan, we conducted a follow-up community-based survey. A total of 173 adults, 82 males and 91 females, with mean age of 55.5 +/- 9.9 years received initial and follow-up anti-HCV tests with one-year interval. One (1.2%, 95% CI: 0%-5.5%) of 84 anti-HCV-positive subjects was negative-seroconversion, and 4 (4.5%, 95% CI: 0.2%-8.8%) of 89 anti-HCV-negative subjects were positive-seroconversion. The results indicated that hepatitis C might be still spreading in the HCV-endemic area now.

Induction of calcium release from isolated sarcoplasmic reticulum by triphenyltin

A direct peripheral myopathy has been found in organotin intoxication and suggested to be a significant factor in the development of muscle weakness following exposure. In this study, by using the isolated sarcoplasmic reticulum membrane vesicles, we have shown that triphenyltin dose-dependently induced Ca2+ release from the actively and passively loaded sarcoplasmic reticulum vesicles. Triphenyltin induced Ca2+ release in ruthenium red-sensitive and insensitive ways with EC50 values of 75 and 270 microM, respectively. The Ca2+-ATPase activity and Ca2+ uptake of sarcoplasmic reticulum were also inhibited by triphenyltin. Triphenyltin exerted dual effects on the apparent [3H]ryanodine binding. Triphenyltin (0.5-10 microM) dose-dependently potentiated the [3H]ryanodine binding; however, the [3H]ryanodine binding decreased as the concentration of triphenyltin increased. The dissociation of bound [3H]ryanodine was facilitated by triphenyltin. The present study suggested that the internal Ca2+ store of skeletal muscle could be depleted by triphenyltin through the inhibition of the Ca2+ uptake and the induction of Ca2+ release by acting on the Ca2+-ATPase and Ca2+ release channel, also known as the ryanodine receptor, of sarcoplasmic reticulum, respectively. These results could partly explain the development of muscle weakness in organotin intoxication; however, their relevance to the development of peripheral myopathy requires further examination.

Different viral aetiology of hepatocellular carcinoma between two hepatitis B and C endemic townships in Taiwan

In Taiwan, we found two hepatitis B virus (HBV)- and hepatitis C virus (HCV)-endemic townships, Paisha and Tzukuan, with an anti-HCV prevalence of 19 and 37% in men, and 26 and 38% in women, respectively. The hepatitis B surface antigen (HBsAg)-positive rates were 25 and 18%, for men and women in Paisha, and 25 and 22% in Tzukuan, respectively. According to the national death certification database (1982 to 1991), the annual age-adjusted mortality rates per 100,000 population for liver cancer among men and women were 83.0 and 13.8, respectively, in Paisha, and 55.9 and 17.0 in Tzukuan compared with 30.9 and 9.1 in Taiwan as a whole. The male-to-female ratios were 6.0 in Paisha and 3.3 in Tzukuan. Aetiology of 11 cases of hepatocellular carcinoma (HCC) from Paisha and 14 cases from Tzukuan were analysed. All HCC cases from Paisha were HBsAg positive, while 13/14 HCC cases from Tzukuan were anti-HCV positive. The endemic duration of HCV in Tzukuan seemed long enough to induce HCC, but the HCV appeared to be a newly introduced infection in Paisha.

Different ultrastructural localization of VIP and prolactin in anterior pituitary cells of rats chronically treated with estrogen

In the present study we investigated the effect of a long-term estrogen treatment on the intracellular distribution of VIP immunoreactivity in pituitary prolactin cells using double-labeling immunocytochemistry. With the use of pre-embedding ABC method it was found that VIP immunoreactivity was associated with the outer surface of membrane-bound organelles, and was not found in secretory granules. However, prolactin immunoreactivity demonstrated by postembedding immunogold technique was mainly associated within the secretory granules of the same cells. The discrepancy between our and Hsu et al.'s results (1989), who observed VIP immunoreactivity in secretory granules of human anterior pituitary cells, may be owing to the overstimulation of VIP cells by estrogen. It is possible that estrogen treatment depleted the VIP content of the secretory granules and enhanced the cytosolic VIP. The appearance of an alternative form of VIP in estrogen-treated rats with preferential distribution in the cytosol cannot be excluded.

Morphometric study of specific heart granules in the grey seal (Halichoerus grypus)

Specific heart granules in the grey seal, Halichoerus grypus, a marine mammal, were studied and compared with those in the Wistar rat by ultrastructural morphometry. There is extreme paucity of these granules in atrial cells of the seal, even in the region of the Golgi apparatus, compared with those in the rat. By numerical concentration, granules in the seal are 23 times fewer in number than in the rat. They are also fewer in number than in bats and hamsters for which data is available. The mean (+/-SEM) diameter of heart granules in the seal is significantly less (188 +/- 5.3 nm) than that of the rat (226 +/- 4.6 nm). These observations, the first in a marine mammal, are of interest in relation to the need for conservation of water and electrolytes in pennipids.

The cellular localization of vasoactive intestinal peptide (VIP) in the mouse median eminence by immuno-electron microscopy

The aim of this study was to examine, by use of pre-embedding immunocytochemistry, the ultrastructural localization of vasoactive intestinal peptide (VIP) immunoreactivity in the mouse median eminence. VIP immunoreactivity was observed in axonal profiles. The VIP-immunoreactive axonal profiles were in close proximity to non-immunoreactive axonal profiles that contained dense granular vesicles and clear vesicles and also to processes of tanycytes. VIP-immunoreactive terminals were observed in the proximity of the perivascular space and in the neuropil. Our results suggest that VIP-immunoreactive axon terminals may possibly interact with other non-immunoreactive axon terminals containing peptide and/or other transmitters at the level of the median eminence or may be released to the portal vasculature thereby to effect anterior pituitary cells.

Prevalence of antibody to hepatitis E virus among healthy individuals in southern Taiwan

The seroprevalence of hepatitis E virus (HEV) among 997 healthy individuals aged 6 to 84 years, collected between July 1993 and June 1994 at Kaohsiung-Pingtung area in Southern Taiwan was studied. Of the study populations of vegetable farmers, elementary school children, volunteer blood donors and college students, the prevalence of IgG anti-HEV ranged from 6.4% to 8.8%. In suburban elemantary school children of Mang-Chou Village at Pingtung-Hsien, the seroprevalence rate (9.6%) was significantly higher than the positive rate (1.5%) found in rural aboriginal elementary school of San-Min Village at Kaohsiung-Hsien. IgG anti-HEV antibodies were widely distributed among all age groups, with a significantly higher percentage (13.1%) in the age group of 46-55 years old.

Seasonal patterns in eating disorder subgroups

Patients with bulimia nervosa (BN) often have seasonal patterns of mood and appetite that compare with patterns seen in seasonal affective disorder (SAD). Seasonal patterns in other eating disorder (ED) subgroups have not been adequately described. We report on seasonal patterns in mood, weight, appetite, sleep, social activity, and energy in 154 consecutive admissions to an outpatient ED program: 60 patients with anorexia nervosa (AN), 31 with BN, 34 with a history of both AN and BN (AN/BN), and 29 with an ED not otherwise specified (ED-NOS). AN patients had significantly less seasonal variation overall than either bulimic subgroup, as measured by the global seasonality score (GSS) on the Seasonal Patterns Assessment Questionnaire (SPAQ). AN patients also showed less seasonal change in mood, weight, and energy than BN patients, and less variation in mood and appetite than AN/BN patients.

Synaptic morphology of substance P terminals on catecholamine neurons in the commissural subnucleus of the nucleus tractus solitarii in the rat

The ultrastructure of substance P-containing nerve terminals synapsing on catecholamine neurons in the rat commissural subnucleus of the nucleus tractus solitarii (NTScom) was studied using a double immunocytochemical labeling technique. Although there were numerous tyrosine hydroxylase-immunoreactive (TH-I) somata present, substance P immunoreactive (SP-I) cell bodies were only occasionally found in the NTScom. At the light microscopic level, many SP-I terminals were seen closely associated with TH-I dendrites and somata. At the electron microscopic level, SP-I terminals synapsing on TH-I structures were also readily encountered. SP-I terminals contained small, clear, and predominantly spherical vesicles (32 +/- 4 nm diameter), as well as large dense-cored vesicles approximately 100 nm in diameter. Postsynaptic TH-I dendritic profiles of various calibers and somata were encountered. These postsynaptic TH-I structures often showed postsynaptic densities. The morphological features of the SP-TH synapses in the present study, that is, the size of synaptic vesicles and the presence of postsynaptic densities, are quite different from those of central carotid sinus afferent synapses reported in our previous study [Chen et al. (1992), J. Neurocytol., 21:137-147]. Therefore, most of the SP terminals of the SP-TH synapses in the NTScom appear not to originate from the carotid sinus afferents. SP-I second-order neurons of the carotid sinus afferent pathway [Chen et al. (1991), J. Auton. Nerv. Syst., 33:97-98] may be one of the possible sources of such terminals.

Synaptic connections of central carotid sinus afferents in the nucleus of the tractus solitarius of the rat. II. Connections with substance P-immunoreactive neurons

A combined transganglionic transport and immunocytochemical technique was used to study the synaptic morphology of central carotid sinus afferents and substance P-immunoreactive neurons in the commissural subnucleus of the nucleus of the tractus solitarius in rats. A large population of substance P-immunoreactive neurons (88.32%) were seen in close association with central carotid sinus afferents by light microscopy. However, many labelled central carotid sinus afferents appeared not associated with substance P-immunoreactive neurons in the nucleus of the tractus solitarius. Substance P-immunoreactive neurons were spindle, pear, or oval-shaped with a short axis ranging from 5 to 11 microns. Their long axis was oriented predominantly in a lateral-medial direction along the path of the central carotid sinus afferents from the solitary tract to the midline. Synaptic contacts between central carotid sinus afferents and substance P-structures, including dendritic profiles of different calibers and somas, were readily found by electron microscopy. Many central carotid sinus afferents were also found in synaptic contact with non-immunoreactive dendrites and somas. Appositions between central carotid sinus afferents and unlabelled axon terminals were common, but only in a few cases were morphological manifestations of synapses revealed. In the latter, the substance P-immunoreactive terminals appeared mostly presynaptic but postsynaptic ones were also encountered. Our data provide the evidence that some of the substance P-immunoreactive cells in the nucleus of the tractus solitarius are 2nd order neurons of the carotid sinus afferent pathway. The possibility that some of the substance P-immunoreactive neurons in the nucleus of the tractus solitarius may be interneurons and mediate carotid sinus afferent inputs to catecholaminergic neurons in the nucleus of the tractus solitarius is considered. Our findings also provide an anatomical substrate for a possible presynaptic modulatory role of central carotid sinus afferents on the inputs from other brain centers to the substance P-neurons in the nucleus of the tractus solitarius.

Heparin treatment enhances the recovery of neoendothelial acetylcholine-induced vascular relaxation after balloon catheter injury in the rabbit aorta

BACKGROUND

After catheter injury, the neoendothelium that grows is abnormal in morphology and in acetylcholine-induced generation of endothelium-derived relaxing factor (EDRF). Heparin has been shown to have stimulatory effects on vascular endothelial growth in vitro. Its effect in vivo on neoendothelial cell morphology and metabolism after injury has not been described. We investigated the effect of heparin treatment on the neoendothelium formed after injury.

METHODS AND RESULTS

Four groups of New Zealand White rabbits were studied. Group 1 rabbits underwent catheter denudation and were killed 4 weeks after injury without receiving treatment (NO Tx, n = 8). Groups 2 and 3 underwent similar aortic injury, received 2 weeks of treatment with either heparin (n = 7) or low molecular weight heparin (LMWH, n = 5), and were killed at 4 weeks. Group 4 underwent sham operation (SHAM, n = 8). EDRF generation was determined by the relaxation of precontracted aortic rings in an organ bath in response to acetylcholine. The heparin-treated group exhibited a significant improvement in acetylcholine-induced relaxation (27%) versus both LMWH-treated (14%, P = .035) and untreated groups (11%, P = .004), although relaxation was only 50% of that observed in the uninjured control vessels (52%, P = .001). The neoendothelium formed in the heparin-treated group exhibited a more normal histological appearance and was aligned with the direction of blood flow as compared with that observed in the untreated or LMWH-treated groups.

CONCLUSIONS

These results demonstrate that in vivo heparin administration enhanced the recovery of EDRF generation and augmented normalization of the morphologic appearance of the neoendothelium.

Angiopeptin enhances acetylcholine-induced relaxation and inhibits intimal hyperplasia after vascular injury

The effects of the somatostatin analogue, angiopeptin (BIM-23014), on neoendothelial function, as evidenced by formation of prostaglandin (PG) I2 and by acetylcholine-induced relaxation (formation of endothelial-derived relaxing factor), were investigated in the rabbit aorta. A balloon catheter injury of the thoracic and abdominal aorta was induced in New Zealand White rabbits. Animals treated with angiopeptin for 2 or 4 wk were compared with untreated rabbits at 2 or 4 wk after the induction of injury, as well as to sham-operated controls. When the rabbits were killed, vascular rings were assessed for arachidonic acid-stimulated PGI2 formation, acetylcholine-induced relaxation, and the degree of intimal hyperplasia. Vascular rings from animals treated with angiopeptin exhibited enhanced acetylcholine-induced relaxation; however, angiopeptin treatment had no effect on arachidonic acid-stimulated PGI2 formation. Intimal hyperplasia in treated animals was reduced by 36%. Treatment with another somatostatin analogue, BIM-23030, did not enhance relaxation or inhibit intimal hyperplasia. These data suggest that treatment with angiopeptin may inhibit intimal hyperplasia in part by its beneficial effect on neoendothelial function.

Differential recovery of prostacyclin and endothelium-derived relaxing factor after vascular injury

Differential recovery of prostacyclin and endothelium-derived relaxing factor after vascular injury. Am. J. Physiol. 262 (Heart Circ. Physiol. 31): H1449-H1457, 1992. The recovery of prostacyclin (prostaglandin I2, PGI2) synthesis and endothelium-derived relaxing factor (EDRF) activity, as demonstrated by acetylcholine (ACh)-induced relaxation, by rabbit aorta was examined up to 8 wk after balloon catheter-induced injury. Following injury, basal 6-keto-PGF1 alpha formation was decreased acutely; however, after 3 wk it was not different from control. Arachidonic acid-stimulated 6-keto-PGF1 alpha formation was decreased, returning to control levels at 3 and 8 wk for thoracic and abdominal aorta, respectively. ACh-induced relaxation did not return to control levels over the 8-wk study. Initiation of reendothelialization with a layer of hyperplastic endothelial cells overlying subendothelial fibrosis and intimal hyperplasia were present at 2-3 wk. Intimal hyperplasia appeared 2 wk after injury and progressed throughout the period of the study. These data indicate that following balloon catheter-induced injury the formation of both PGI2 and EDRF is reduced and that recovery follows a differential time course. In addition, the recovery of PGI2 formation did not coincide with the attenuation of intimal hyperplasia, whereas the relationship between EDRF formation and intimal hyperplasia is uncertain.

Synaptic connections of central carotid sinus afferents in the nucleus of the tractus solitarius of the rat. I. An electron microscopic study

A transganglionic transport technique was used to study the synaptic connections of the central carotid sinus afferents in the nucleus of the tractus solitarius of the rat by electron microscopy. The caudal part of the nucleus was profusely innervated. Labelled fibres extended to the contralateral nucleus, and to the ipsilateral dorsal motor nucleus of the vagus nerve, nucleus ambiguus, spinal nucleus of the trigeminal nerve and the area postrema. The labelled terminals were densely packed with clear, predominantly spherical vesicles about 50 nm in diameter and a few often swollen mitochondria. The terminals synapsed on dendrites of various calibres, spindle- or pear-shaped somal profiles with short axes lesser than 8 microns, and axon terminals. In axo-axonal synapses, most labelled terminals appeared to be presynaptic. Frequently, profiles of labelled terminals were in direct apposition with one another. The latter may represent the morphological substrate of the interaction between baro- and chemoreceptor inputs in the nucleus of the tractus solitarius and warrants further study. The present results indicate that in addition to direct inputs, the carotid sinus afferents are able to influence second-order neurons in the nucleus of the tractus solitarius indirectly through presynaptic modulation.

The pretectal complex of the cat: cells of origin of projections to the pulvinar nucleus

The pretectal projection to the pulvinar nucleus in the cat was examined using the retrograde transport of wheat germ agglutinin-horseradish peroxidase. These data show that both visual and non-visual areas of the pretectal complex contribute to the projection. Specifically, large numbers of labeled neurons are located within the pretectal olivary nucleus with a substantial number of labeled neurons observed within the nucleus of the optic tract. Labeled neurons are also located within the medial, anterior and posterior nuclei, but not to the degree observed in the other pretectal nuclei. Morphometric analysis of labeled and Nissl-stained neurons indicate that the pretectopulvinar pathway is not correlated to any single cell size.

Light and electron microscopic studies of diet-induced hepatic changes in mice

Adult mice were fed a choline-deficient ethionine enriched (CDE) diet for 24, 48 or 72 h. They were then fasted for 24 or 48 h prior to sacrifice. All tissues were studied by light and electron microscopy. Animals fed the CDE diet for 24 h exhibited cells with vacuolated cytoplasm, and the accumulation of lipid in these cells was clearly abnormal. Animals fed the CDE diet for 24 h and subsequently a regular diet for 48 h displayed normal hepatocytes, suggesting that the alterations at 24 h were reversible. Following 48 or 72 h of feeding the CDE diet, abundant lipid-laden cells were observed in the hepatic lobules, and at the electron microscope level these cells were undergoing frank degeneration. Evidence indicated that changes after 48 or 72 h were irreversible.

Effects of dibutyryl adenosine 3',5'-cyclic monophosphate on erythropoietin production in human renal carcinoma cell cultures

A human renal carcinoma from a patient with erythrocytosis, serially transplanted into athymic nude mice, was grown in primary monolayer cell cultures. After reaching confluency, the cultured cells formed multicellular hemicysts (domes), which became more abundant as the cultures approached saturation density. Erythropoietin (Ep) production by this renal carcinoma in culture was only slightly increased at the time of semiconfluency but showed a marked increase after the cultures reached confluency, in parallel with dome formation. Dibutyryl adenosine 3',5'-cyclic monophosphate significantly (P less than .01) stimulated Ep production and dome formation in the semiconfluent and confluent cultures of the renal carcinoma.

Dopamine beta-hydroxylase-like immunoreactivity in the rat and cat carotid body: a light and electron microscopic study

Immunocytochemical localization of dopamine beta-hydroxylase (DBH) was used to study the synthesis and storage sites of norepinephrine (noradrenaline) in the rat and cat carotid bodies. In the rat carotid body some parenchymal cells exhibited strong DBH-like immunoreactivity (DBH-I), while others displayed only faint DBH-I. In a typical parenchymal cell cluster, most cells with strong DBH-I were irregular in shape and appeared to partially surround those with weak DBH-I which usually were rounded in contour. In the cat carotid body most parenchymal cells showed a strong to moderate DBH-I. In both the rat and cat carotid bodies varicose nerve fibres with DBH-I were associated primarily with blood vessels. All autonomic ganglion cells examined, which were associated with the rat carotid body, showed DBH-I. Electron microscopy revealed that most DBH-I in the strongly positive cells of the rat carotid body was associated with dense granules (possibly corresponding to dense-cored vesicles of various sizes), although some was found in other sites. In oval cells with less DBH-I, reactivity resided in some of the large granules. In the cat carotid body the glomus cells contained more granules of various sizes and shapes than did those of the rat carotid body. Most of the cat glomus cell granules exhibited DBH-I activity. Our results indicate that some of glomus cells in the rat and most of the glomus cells in the cat contain DBH and therefore may be sites of norepinephrine synthesis.

Erythropoietin production in long-term cultures of human renal carcinoma cells. The role of cell population density

The present studies report the maintenance of erythropoietin (Ep) production in long-term cultures of a human renal carcinoma from a patient with erythrocytosis. The renal carcinoma cells were grown and maintained in monolayer cultures for 7 months. They were serially passaged every 2-3 weeks when the cultured cells reached confluency. Ep levels measured with a sensitive radioimmunoassay in the spent culture media of the cells in the stage of semiconfluent or confluent density were less than 20 and 30 mU/ml, respectively, throughout the period of 15 successive passages. However, when the renal carcinoma cells were maintained in culture without passage after reaching confluency, Ep levels in the spent media of these cells reproducibly showed an exponential increase to more than 300 mU/ml at the time of saturation density. The importance of cell population density in Ep production by the renal carcinoma cell cultures was further confirmed by the observation that the cultures with higher seeding density reached confluency earlier and began an exponential increase in Ep production sooner than those cultures with lower seeding density.

Role of endogenous prostaglandin E2 in erythropoietin production and dome formation by human renal carcinoma cells in culture

Studies were carried out on the role of endogenous prostaglandin E2 (PGE2) in erythropoietin (Ep) production and dome formation in primary monolayer cultures of a human renal carcinoma from a patient with erythrocytosis that has been serially transplanted into BALB/c athymic nude mice. The metabolism of [14C]arachidonic acid (14C-AA) by cultured renal carcinoma cells, which were plated in 25-cm2 flasks at a density of 2 X 10(4) cells/cm2 and grown for 6, 12 (confluence, 13 X 10(4) cells/cm2), 16, 24, and 30 d in Eagle's minimum essential medium (MEM) supplemented with 10% fetal bovine serum, was examined by using radiometric thin-layer chromatography (TLC). TLC revealed PGE2 to be the major metabolite of 14C-AA produced by the cultured cells throughout the 30 d of cultivation. In addition, the cultured cells at each time period were incubated for 24 h in 5 ml of serum-free Eagle's MEM and the levels of PGE2 and Ep in the incubated media were measured via radioimmunoassay. PGE2 levels in the serum-free media incubated with the cultured cells grown for 6 d were significantly (P less than 0.001) elevated (174 +/- 2.5 pg/ml, n = 5), compared with the unincubated control media (1.5 +/- 0.19 pg/ml, n = 5) and gradually decreased at each time period to 97.6 +/- 4.4 pg/ml (n = 5) at 30 d. On the other hand, the levels of Ep in the incubated media of the cells grown for 6 d were 11.5 +/- 0.52 mU/ml (n = 5) compared with 7.6 +/- 0.62 mU/ml (n = 5) in the control media. However, after the cultured cells became confluent, the levels of Ep in the incubated media showed a marked increase to 222.9 +/- 5.26 mU/ml (n = 5) at 30 d of cultivation. Multicellular hemicysts (domes) developed after the cultured cells reached confluence and their numbers increased with increasing time in confluence in parallel with the increase in Ep. Meclofenamate (MF) (3 X 10(-6)-3 X 10(-5) M), a prostaglandin synthesis inhibitor, produced a significant dose-related decrease in PGE2, Ep, and dome formation without producing a significant effect on cell viability in the 30-d cells. This inhibitory effect of MF on Ep production and dome formation was completely abolished by the addition of 10(-8) M PGE2 to the incubation medium. In conclusion, endogenous PGE2 plays an important role in supporting and/or stimulating Ep production and dome formation in cultured renal carcinoma cells.

Erythropoietin production in a primary culture of human renal carcinoma cells maintained in nude mice

The present studies report erythropoietin (Ep) production in primary cultures of a human renal carcinoma from a patient with erythrocytosis that has been serially transplanted to BALB/c nude mice. The levels of erythropoietin in the culture media were estimated using the exhypoxic polycythemic mouse assay (EHPCMA), fetal mouse liver erythroid colony-forming technique (FMLC), and a radioimmunoassay (RIA). The spent culture media of the exponentially growing cells contained less than 10 mU/ml of Ep measured by RIA. However, after the cells became confluent, Ep levels (RIA) in the spent media showed a marked increase to approximately 300 mU/ml. Ep levels estimated using the FMLC and EHPCMA were approximately 2/3 and 1/10, respectively, of those measured by RIA. Rabbit antiserum to highly purified human urinary Ep (70,400 U/mg protein) was utilized for immunocytochemical (peroxidase-antiperoxidase method) localization of Ep in the cultured cells. Very few of the cells in exponential growth exhibited Ep-like immunoreactivity, whereas intense Ep-like immunoreactivity was observed in the cytoplasm of the cells maintained in culture for a prolonged period after reaching confluency. The most intense staining was observed in some of the cells forming domes. The domes developed after the cells reached confluency, and their numbers increased with increasing time in confluent culture, in parallel with the increase in Ep levels in the spent media. This primary cell culture system of a renal cell carcinoma maintained in nude mice, which produces immunologically and biologically active Ep, may provide a useful model for studies of the mechanism of Ep production.

Two types of glomus cell in the rat carotid body as revealed by alpha-bungarotoxin binding

Horseradish peroxidase (HRP)-conjugated alpha-bungarotoxin (alpha Bgt) was used to localize alpha Bgt-acetylcholine receptor sites in the rat carotid body. Two types of glomus cell were differentiated on the basis of the staining of their plasma membranes by the conjugate: type A, devoid of staining or only partly stained; and type B, exhibiting staining over the entire cell surface. The parts of type A glomus and supporting cells stained were always in direct apposition to type B glomus cells. It is concluded that type B glomus cells are possibly the only cell types exhibiting specific binding sites of alpha Bgt. Other morphological characteristics and quantitative studies indicated that the type A and type B glomus cells presented in this study were equivalent to those described in the rat carotid body by other investigators (McDonald & Mitchell, 1975). alpha Bgt-HRP staining facilitated the observation of the distribution pattern of glomus cells in the parenchyma: type A glomus cells were arranged in groups and often showed polarity toward neural elements and sinusoidal capillaries; and clusters of type B glomus cells were frequently situated in a demilune -like fashion over groups of type A glomus cells. Because of differences in morphology, synaptology, alpha Bgt-binding affinity, and polarity toward the blood vessels, we propose that type A and type B glomus cells in the rat carotid body represent functionally distinct cell types.

Light and electron microscopic localization of ATPase in normal and degenerating testes of Syrian hamsters

The distribution of Mg++-activated ATPase was determined with light and electron microscopy in normal and degenerating seminferous tubules. In the normal animals ATPase was localized in the interface between spermatids and Sertoli cells, in association with the cytoplasmic filaments contained within Sertoli cell processes, and in the lymphatic endothelium. ATPase activity increased in degenerating tubules as observed by light microscopy. Electron microscopic investigations of the degenerating tubules which contained only spermatogonia and Sertoli cells revealed reaction product on the outer surface of the Sertoli cell processes and within the interface between adjacent Sertoli cells. Reactaction product was also observed in the Sertoli cell processes between the cytoplasmic filaments and the cell membrane. Where filaments were absent in Sertoli cell processes, no reaction product was observed. These electron microscopic studies indicate that the increase in ATPase activity in testicular degeneration is probably a relative increase due to a loss of the germinal elements of the tubular epithelium and subsequent apposition of the Sertoli cell processes. We speculate that the ATPase activity localized within the Sertoli cell processes may be involved in providing an energy source for filament motility.

An electron microscopic study on the effects of reserpine on the subclavian glomera of the rabbit

Young male and female New Zealand white rabbits were given a daily subcutaneous injection of reserpine (Serpasil, Ciba; 3 mg/kg) for two days and were sacrificed 24 hours after the last injection. The subclavian glomera (aortic bodies) were processed for electron microscopy to determine the effects of this biogenic amine depleting agent on the electron-opaque cytoplasmic granules of the parenchymal type I cells. Observations of glutaraldehyde-osmium tetroxide fixed glomera from reserpinized animals showed a slight decrease in granule density of the type I cells. Glomera fixed in glutaraldehyde and incubated in potassium dichromate (pH 4.1) demonstrated a reduction in granule opacity following reserpine treatment. Control glomera incubated in potassium dichromate displayed electron-opaque granules. These results indicate that reserpine does deplete the amines without granule disappearance or changes in granule population. The positive reaction of the control tissue granules to potassium dichromate incubation suggests that the predominant biogenic amines in the electron-opaque granules are unsubstituted monoamines. Persistence of the opaque granules following reserpinization and glutaraldehyde-osmium tetroxide double fixation, may be due to amine-binding protein within the granules. The mode of granule depletion could not be ascertained with certainty.

A glutaraldehyde/potassium dichromate tracing method for the localization and preservation of abdominal extra-adrenal chromaffin tissues

The present work introduces a method for the localization in situ of the abdominal paraganglia. After treating retroperitoneal tissue blocks with a near-neutral glutaraldehyde/potassium dichromate solution following routine glutaraldehyde perfusion, intra- and extraadrenal chromaffin tissues develop a pronounced brown color from the interaction of glutaraldehyde/potassium dichromate with amines. In this manner, visualization of the abdominal extra-adrenal chromaffin organs is enhanced at the same time that cellular ultrastructure is preserved. Subsequent examination of the dichromate-reacted tissues with the electron microscope confirms that they represent the amine-rich paraganglia. This method offers an effective alternative to extensive sampling of plastic-embedded blocks for localizing peripheral chromaffin tissue and has been used to define the exact distribution of abdominal paraganglia in the rabbit.

The fine structure and phosphatase cytochemistry of the golgi complex and associated structures in the sertoli cells of Syrian hamsters

The Golgi complex in the Sertoli cell of the Syrian hamster is well developed and consists of stacks of cisternae and associated vesicles. The inner- and outermost cisternae of the Golgi stacks are usually moderately dilated and exhibit numerous fenestrations. The middle portions of the intermediate cisternae are greatly flattened and not fenestrated, but toward the periphery these cisternae gradually become dilated and show a few fenestrations. On the inner aspect of the Golgi stacks the following structures are seen frequently: (1) one or two series of linearly arrayed circular profiles some of which are interconnected by tubules; (2) networks of anastomosing tubules with circular or oval meshes (800 to 1200 A in diameter); and/or (3) irregularly disposed tubules. The circular profiles and tubules are approximately 450 A in diameter. Acid phosphatase activity was localized in these anastomosing tubules when the tissues were incubated for more than one hour in a modified Gomori's medium (Barka and Anderson, 1963). Strong thiamine pyrophosphatase activity was demonstrated in the inner one to three cisternae of the Golgi stacks but not in the associated tubules. The system of the Golgi associated tubules is morphologically and histochemically distinct from the Golgi stacks and is probably equivalent to the Golgi-endoplasmic reticulum-lysosome system (GERL) in other cell types. The three dimensional aspects of the GERL-equivalent system are discussed.