A Feasibility Study on a Portable Vision Device for Patients with Stroke and Brain Tumours

This prospective, single-centre cohort study aimed to evaluate the impact of a portable vision reading device, OrCam Read, on vision-related quality-of-life and independent functional status in patients with low vision due to stroke or brain tumours. Six patients with poor visual acuity or visual field defects due to a stroke or a brain tumour were enrolled at a U.S. Ophthalmology Department. Participants were trained to use OrCam Read and given a loaner device for the 1 month duration of the study. Various assessments, including daily function tests, the National Eye Institute Visual Function Questionnaire-25, and the 10-item neuro-ophthalmic supplement, were administered at the first and last visits. Patients' experience with the device was evaluated with weekly telephone and end-of-study satisfaction surveys. The main outcome measures were the patient satisfaction with OrCam and the mean assessment scores between enrolment and final visits. The intervention with OrCam significantly improved patients' ability to complete daily tasks and participants reported good satisfaction with the device. The results also show non-significant improvement with distant activities, dependency, and role difficulties. Our findings demonstrate the feasibility of studying vision-related quality-of-life using a portable vision device in this patient population and pave the way for a larger study to validate the results of this study.

Racial, Ethnic, and Gender Diversity in United States Ophthalmology Clinical Trials

Purpose

To investigate the representation of various gender, racial, and ethnic groups in ophthalmology clinical trials conducted in the United States (US) between 1997 and 2022.

Design

Retrospective cross-sectional study.

Participants

We included all participants in completed phase II/III, III, and IV ophthalmology clinical trials reported on the ClincialTrials.gov database.

Methods

The proportional enrollment of each racial/ethnic and gender group in the clinical trials was calculated and compared with the US population. We also investigated the impact of various clinical trial features on the rate of reporting demographic information and enrollment of minorities.

Main Outcome Measures

Proportional enrollment of each gender and race/ethnicity group compared with the US Census.

Results

Of the total clinical trials included in the study, less than half (43.6%) provided information on the racial or ethnic backgrounds of their participants. The majority of the enrollees in trials were female (median: 57.5%, interquartile range [IQR]: 47.2%-65.8%). Among the trials that reported race and/or ethnicity data, White populations were overrepresented (median: 76.6%, IQR: 69.0%-84.0%, P = 0.001), and minorities, including Asian, Hispanic, and "other" groups, were underrepresented compared with the 2010 US Census (P < 0.001). Enrollment of Black individuals was found to be comparable to the US population estimates (median: 12.4%, IQR: 6.2%-20.8%, P = 0.44). The trial phase, the number of study participants, the primary clinical condition, and the year the trial started all affected demographic reporting and minority enrollments.

Conclusions

Our findings highlight the need for increased efforts to promote diversity and inclusivity in ophthalmology clinical trials. Ensuring equitable inclusion of different gender, racial, and ethnic groups in the trials is essential for minimizing disparities and producing unbiased scientific findings generalizable to the entire population.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Neuro-ophthalmic features of patients with spontaneous cerebrospinal fluid leaks

Background

Increased intracranial pressure is a potential cause of spontaneous cerebrospinal fluid (sCSF) leak. Associated neuro-ophthalmic features have not been well studied, particularly relationships with idiopathic intracranial hypertension (IIH). We hypothesized that neuro-ophthalmic features routinely used in evaluations for IIH can be useful in the investigation of a causal relationship between IIH and sCSF leak. We reviewed the neuro-ophthalmic examination and office-based ophthalmic imaging data of all consecutive patients with sCSF leaks and at least one repair to investigate the clinical and neuro-ophthalmic features of increased intracranial pressure.

Methods

We conducted a retrospective longitudinal study at a single institution by querying the electronic medical record system for CSF leak Current Procedural Terminology (CPT) codes (G96.00 and G96.01) from June 1, 2019, to July 31, 2022. For patients with a confirmed diagnosis of sCSF leak, demographic information, eye examination results, and ophthalmic imaging details for both eyes were collected.

Results

A total of 189 patients with CSF leaks were identified through CPT coding; 159 had iatrogenic or traumatic CSF leaks, and 30 individuals (3 male, 27 female) had confirmed sCSF leaks. The mean age of patients with sCSF leaks was 46 years (range: 29 - 81), with a mean body mass index of 35.2 kg/m2 (range: 18.2 - 54.1). Only 11 of 30 underwent eye examinations (8 before surgical repair and 10 after). The mean pre-repair and post-repair best-corrected visual acuity were 20/30 (range: 20/20 - 20/55) and 20/25 (range: 20/20 - 20/40), respectively (P = 0.188). The mean retinal nerve fiber layer thickness was 99 µm (range: 96 - 104) pre-repair and 97 µm (range: 84 - 103) post-repair (P = 0.195). The mean ganglion cell complex thickness was 84 µm (range: 72 - 94) pre-repair and 82 µm (range: 71 - 94) post-repair (P = 0.500). Humphrey visual field average mean deviation was -5.1 (range: -12.4 - -1.8) pre-repair and -1.0 (range: -10.1 - 2.1) post-repair (P = 0.063).

Conclusions

Serial neuro-ophthalmic examinations are recommended for patients with sCSF leaks to screen for signs of current or prior increased intracranial pressure. Larger studies are required to clarify the longitudinal changes in neuro-ophthalmic features, to investigate the incidence of IIH in cases of sCSF leak development or recurrence after surgical repair, and to explore potential causal relationships to guide post-repair management and prevent recurrent leaks. A multicenter consortium is also suggested to develop a standard clinical protocol for comprehensive management of sCSF leaks.

Combined central retinal artery and medial posterior ciliary artery occlusion: Localizing the lesion

Purpose

To report a rare case of a combined central retinal artery (CRA) and medial posterior ciliary artery (MPCA) occlusion due to an atherosclerotic lesion in the common trunk supplying both arteries.

Observations

A 75-year-old man presented with acute vision loss associated with elevated intraocular pressure in the right eye. Multi-modal imaging revealed a combined retinal and choroidal infarction in the distribution of the CRA and MPCA, localizing the lesion to the common trunk of the ophthalmic artery supplying both the CRA and MPCA. Neurovascular imaging provided supportive evidence for the diagnosis.

Conclusions and importance

A simultaneous retinal and choroidal vascular occlusion is an uncommon presentation. Familiarity with the anatomy of the ophthalmic arteries and its branches facilitates localizing the lesion.

Application of Machine Learning to Metabolomic Profile Characterization in Glioblastoma Patients Undergoing Concurrent Chemoradiation

We here characterize changes in metabolite patterns in glioblastoma patients undergoing surgery and concurrent chemoradiation using machine learning (ML) algorithms to characterize metabolic changes during different stages of the treatment protocol. We examined 105 plasma specimens (before surgery, 2 days after surgical resection, before starting concurrent chemoradiation, and immediately after chemoradiation) from 36 patients with isocitrate dehydrogenase (IDH) wildtype glioblastoma. Untargeted GC-TOF mass spectrometry-based metabolomics was used given its superiority in identifying and quantitating small metabolites; this yielded 157 structurally identified metabolites. Using Multinomial Logistic Regression (MLR) and GradientBoostingClassifier (GB Classifier), ML models classified specimens based on metabolic changes. The classification performance of these models was evaluated using performance metrics and area under the curve (AUC) scores. Comparing post-radiation to pre-radiation showed increased levels of 15 metabolites: glycine, serine, threonine, oxoproline, 6-deoxyglucose, gluconic acid, glycerol-alpha-phosphate, ethanolamine, propyleneglycol, triethanolamine, xylitol, succinic acid, arachidonic acid, linoleic acid, and fumaric acid. After chemoradiation, a significant decrease was detected in 3-aminopiperidine 2,6-dione. An MLR classification of the treatment phases was performed with 78% accuracy and 75% precision (AUC = 0.89). The alternative GB Classifier algorithm achieved 75% accuracy and 77% precision (AUC = 0.91). Finally, we investigated specific patterns for metabolite changes in highly correlated metabolites. We identified metabolites with characteristic changing patterns between pre-surgery and post-surgery and post-radiation samples. To the best of our knowledge, this is the first study to describe blood metabolic signatures using ML algorithms during different treatment phases in patients with glioblastoma. A larger study is needed to validate the results and the potential application of this algorithm for the characterization of treatment responses.

A Co-Designed Neuromorphic Chip With Compact (17.9K F2) and Weak Neuron Number-Dependent Neuron/Synapse Modules

Many efforts have been made to improve the neuron integration efficiency on neuromorphic chips, such as using emerging memory devices and shrinking CMOS technology nodes. However, in the fully connected (FC) neuromorphic core, increasing the number of neurons will lead to a square increase in synapse & dendrite costs and a high-slope linear increase in soma costs, resulting in an explosive growth of core hardware costs. We propose a co-designed neuromorphic core (SRCcore) based on the quantized spiking neural network (SNN) technology and compact chip design methodology. The cost of the neuron/synapse module in SRCcore weakly depends on the neuron number, which effectively relieves the growth pressure of the core area caused by increasing the neuron number. In the proposed BICS chip based on SRCcore, although the neuron/synapse module implements 1∼16 times of neurons and 1∼66 times of synapses, it only costs an area of 1.79 × 10⁷ F², which is 7.9%∼38.6% of that in previous works. Based on the weight quantization strategy matched with SRCcore, quantized SNNs achieve 0.05%∼2.19% higher accuracy than previous works, thus supporting the design and application of SRCcore. Finally, a cross-modeling application is demonstrated based on the chip. We hope this work will accelerate the development of cortical-scale neuromorphic systems.

TMET-08. METABOLOMIC CHANGES IN GLIOBLASTOMA PATIENTS UNDERGOING CONCURRENT CHEMORADIATION THERAPY

OBJECTIVE

To illustrate changes of untargeted metabolomics in patients with glioblastoma IDH wildtype undergoing concurrent radiation therapy (RT) with temozolomide (TMZ). This study implemented machine learning (ML) algorithms to predict treatment phase: pre-surgery, post-surgery, pre-radiation, and post radiation based on untargeted metabolomics data.

METHODS

Thirty-six patients with glioblastoma IDH wildtype (18 methylguanine methyltransferase [MGMT] methylated, 16 MGMT unmethylated, 2 MGMT status unknown) were enrolled into this study. Serum samples obtained from patients on the same day before surgery, 2 days after surgery, before starting their concurrent chemoradiation, and after concluding this phase of treatment. Blood samples were obtained via antecubital phlebotomy without regard for time of the day, diet, or fasting status. Untargeted metabolomics by GC-TOF mass spectrometry were obtained and compared. The proposed ML models analyzed 105 samples from 36 patients utilizing 157 structurally identified blood metabolites. Multinomial Logistic Regression (MLR) and GradientBoostingClassifier (GB Classifier) were used to classify patient samples based on detected changes in blood metabolites. The classification performance of these models was evaluated using performance metrics and AUC scores.

RESULTS

Post radiation; significant increase in the following metabolites: glycine, serine, threonine, oxoproline, 6-deoxyglucose, gluconic acid, glycerol-alpha-phosphate, ethanolamine, propyleneglycol, triethanolamine, xylitol, and fumaric acid were noted while significant decrease in 3-aminopiperidine 2,6-dione was noted post radiation. MLR produced 78% accuracy, 75% precision, and AUC = 0.89, and GB Classifier produced 75% accuracy, 77% precision and AUC = 0.91. Finally, we presented a pattern of metabolites changes per clinical stage based on pairwise correlations.

CONCLUSIONS

This study represent the first serum metabolic signature associated with RT in patients with glioblastoma. The results from the classification algorithms and pairwise correlations showed that blood metabolites have the potential to predict phase of treatment and potentially enable to evaluate response to treatment in patients with glioblastoma in a relatively small cohort.

NCOG-15. A PILOT STUDY ON RETINAL FEATURES AND COGNITIVE FUNCTION IN PATIENTS WITH LOW GRADE GLIOMAS

BACKGROUND

Retinal structure and vascular changes are used as biomarkers for preclinical Alzheimer disease. We conducted a cohort study to evaluate the feasibility of obtaining these data in patients with low-grade gliomas (LGGs) who completed chemoradiation therapy with and without self or family reported cognitive concerns.

METHODS

Optical coherence tomography (OCT) and angiography (OCTA, OptoVue, Inc.) images were obtained from 6 LGG patients and 2 healthy controls using 4.5 x 4.5 mm peripapillary and 6x6 mm macular scan patterns. We measured OCTA parameters including radial peripapillary capillary density for the peri-optic disc region, whole macular density, and foveal avascular zone (FAZ).

RESULTS

We analyzed two eyes of two control subjects, an LGG patient with normal cognition, and 5 LGG patients with cognitive impairment (mean age 45 years, range of 3 months to 10 years after chemoradiation). Both controls had normal eye exams. Average retinal nerve fiber layer thickness was thinner in patients with and without cognitive dysfunction (104 um and 106 um, respectively) than controls (123 um). A similar pattern was seen in macula thickness (283 um and 290 um vs. 325 um). The average peripapillary vessel densities were lower in patients with and without cognitive dysfunction (47.7% and 48.3%, respectively) than controls (51.9%). The whole macular vessel densities were similar in three groups (46.7 %, 48.0%, and 48.0 %). Average FAZs were larger in patients with cognitive dysfunction (0.254 mm2) than the patient with normal cognition (0.204 mm2) and controls (0.226 mm2).

CONCLUSIONS

Retinal architecture and microvascular changes measured by OCT/OCTA is feasible in LGG patients after chemoradiation. A larger prospective study is needed to investigate the role of OCT/OCTA in detecting peripapillary and perifoveal changes in brain tumor patients with treatment-associated cognitive dysfunction.

A Kazal-type serine protease inhibitor mediates innate immunity in wild silkworm Actias selene Hübner

The prophenoloxidase (PPO) activation system is an important innate immune defense mechanism in arthropods. Actias selene is a rare and important wild silk insect that can spin high-quality cocoon silk, but, other than its morphology, its molecular mechanism is rarely reported. Here, we report the purification and characterization of a novel KSPI gene from A. selene (AsKSPI, which can negatively regulate PPO activation. Its open reading frame (ORF) was 291 bp, encoding 96 amino acids. Real-time quantitative PCR (RT-qPCR) showed that AsKSPI mRNA was significantly expressed in the fat body. Immunostimulatory tests showed that the mRNA levels of AsKSPI in the fat body were up-regulated following injection of Micrococcus luteus, Escherichia coli, Beauveria bassiana, and nuclear polyhedrosis virus (NPV). Enzyme activity experiments showed that the purified recombinant AsKSPI could inhibit the activation of PPO in hemolymph of A. selene, but did not affect phenoloxidase (PO) activity after PPO had been activated. So, AsKSPI could regulate the innate immunity of A. selene through the PPO cascade. These findings will contribute to the understanding of the immune mechanism of wild silkworm and provide a basis for better protection and utilization of special economic insect resources.

The basic science of optic nerve regeneration

Diverse insults to the optic nerve result in partial to total vision loss as the axons of retinal ganglion cells are destroyed. In glaucoma, axons are injured at the optic nerve head; in other optic neuropathies, axons can be damaged along the entire visual pathway. In all cases, as mammals cannot regenerate injured central nervous system cells, once the axons are lost, vision loss is irreversible. However, much has been learned about how retinal ganglion cells respond to axon injuries, and many of these crucial discoveries offer hope for future regenerative therapies. Here we review the current understanding regarding the temporal progression of axonal degeneration. We summarize known survival and regenerative mechanisms in mammals, including specific signaling pathways, key transcription factors, and reprogramming genes. We cover mechanisms intrinsic to retinal ganglion cells as well as their interactions with myeloid and glial cell populations in the retina and optic nerve that affect survival and regeneration. Finally, we highlight some non-mammalian species that are able to regenerate their retinal ganglion cell axons after injury, as understanding these successful regenerative responses may be essential to the rational design of future clinical interventions to regrow the optic nerve. In the end, a combination of many different molecular and cellular interventions will likely be the only way to achieve functional recovery of vision and restore quality of life to millions of patients around the world.

Telemedicine for neuro-ophthalmology: challenges and opportunities

PURPOSE OF REVIEW

Telemedicine for neuro-ophthalmology (tele-neuro-ophthalmology) has the potential to increase access to neuro-ophthalmic care by improving efficiency and decreasing the need for long-distance travel for patients. Requirements for decreased person-to-person contacts during the COVID-19 pandemic accelerated adoption of tele-neuro-ophthalmology. This review highlights the challenges and opportunities with tele-neuro-ophthalmology.

RECENT FINDINGS

Tele-neuro-ophthalmology programs can be used for triage, diagnostic consultation, and long-term treatment monitoring. Formats include telephone appointments, interprofessional collaborations, remote data interpretation, online asynchronous patient communication, and video visits. Barriers to long-term implementation of tele-neuro-ophthalmology arise from data quality, patient engagement, workflow integration, state and federal regulations, and reimbursement. General neurologists may collaborate with local eye care providers for ophthalmic examination, imaging, and testing to facilitate efficient and effective tele-neuro-ophthalmology consultation.

SUMMARY

Tele-neuro-ophthalmology has tremendous potential to improve patient access to high-quality cost-effective neuro-ophthalmic care. However, many factors may impact its long-term sustainability.

Aggressive FUS-Mutant Motor Neuron Disease Without Profound Spinal Cord Pathology

A 29-year-old man presented with rapidly progressive severe neck weakness, asymmetrical bilateral upper extremity weakness, bulbar dysfunction, profound muscle wasting, and weight loss. Within 1 year, his speech became unintelligible, he became gastrostomy- and tracheostomy/ventilator-dependent, and wheelchair bound. Electrophysiology suggested motor neuron disease. Whole exome sequencing revealed a heterozygous pathogenic variant in the fused in sarcoma gene (FUS), c.1574C>T,p. R525L, consistent with autosomal dominant amyotrophic lateral sclerosis. Autopsy revealed extensive denervation atrophy of skeletal musculature. Surprisingly, there was only minimal patchy depletion of motor neurons within the cervico-thoracic spinal cord anterior horn cells, and the tracts were largely preserved. TDP-43 inclusions were absent. Abnormal expression of FUS mutation product (cytoplasmic inclusions) was demonstrated by immunohistochemistry within anterior horn motor neurons. The most prominent finding was a disparity between profound neck weakness and relatively low-grade anterior horn cell loss or tract degeneration in the cervico-thoracic cord.

Analysis of soluble urokinase plasminogen activator receptor in multiple myeloma for predicting prognosis

Multiple myeloma is a type of malignancy, which affects the plasma cells of the bone marrow. Recent studies have found that malignant plasma cells may express urokinase plasminogen activator (uPA) and uPA receptor (uPAR), and that initiation of proteolytic events by this system contributes to the process of invasion and destruction of the bone marrow. Studies have also suggested that the level of the soluble form of uPAR (suPAR) may act as a marker for prognosis in patients with multiple myeloma, and that there is an association between uPAR/suPAR expression, and clinical characteristics, efficacy of treatment in disease control and patient survival. In order to investigate this, the present study used flow cytometry to detect the monoclonal antibodies associated with multiple myeloma, specifically, uPAR (CD87), CD56 and CD38. Patients with multiple myeloma were divided into the following groups: The effective groups (remission and stable disease) and the ineffective group (progressive disease). suPAR expression in the effective groups was 257.6±32.47 pg/ml and 331.0±99.80 pg/ml respectively, which was not significantly different from that of the normal control group (P>0.05). By contrast, the suPAR level in the invalid group was 562.2±291.0 pg/ml, which was significantly different from the levels in the normal control group (P<0.01) and the effective groups (P<0.05). suPAR levels were positively correlated with disease stage (P<0.01), renal function (P<0.05), C-reactive protein (P<0.005), β2-microglobulin (P<0.001), extramedullary involvement (P<0.001), chromosome 13 deletion (P<0.01) and survival >2 years (P<0.01). They were was negatively correlated with hemoglobin concentration. No correlation was observed between uPAR expression and suPAR levels. The present study also indicated that the stage of disease and suPAR expression were independent factors, which predicted survival of <2 years. In conclusion, high suPAR expression appears to predict disease progression, a shortened survival period and early extramedullary infiltration.

3-D imaging, illustration, and quantitation of enteric glial network in transparent human colon mucosa

BACKGROUND

Enteric glia form a network in the intestinal mucosa and have been suggested to engage in multidirectional interactions with the epithelium, blood vessels, nerves, and immune system. However, due to the dispersed nature of the glial network, standard histology cannot provide a global view of the network architecture. We prepared transparent human colon mucosa for three-dimensional (3-D) confocal microscopy with S100B immunostaining to reveal the location-dependent glial network for qualitative and quantitative analyses.

METHODS

Full-thickness human colons were acquired from colectomies performed for colorectal cancer. We targeted the mucosa away from the tumor site to characterize the glial network morphology. Optical clearing (use of immersion solution to reduce scattering) was applied to generate transparent specimens for deep-tissue microscopy.

KEY RESULTS

Two features of the glial network were seen: (i) A dense glial population resides at the crypt base/mucosal boundary in contact with the lymphatic vessels, and (ii) from the base, the glial network elongates along the crypt axis with peri-cryptic and peri-vascular connections toward the opening. We quantified the mucosal glia as the S100B-positive cells with at least two processes extending from the cell body. Examples of the global and in-depth imaging of adenoma were given to illustrate the morphological correlation between the loss of glial fibers and the aberrant crypts.

CONCLUSIONS & INFERENCES

We have established a useful approach for 3-D imaging, panoramic illustration, and quantitation of the enteric glia in the human colon mucosa to help characterize their roles with mucosal components in health and disease.

Deletion of the endothelin-A-receptor suppresses oxygen-induced constriction but not postnatal closure of the ductus arteriosus

Experiments were carried out in mutant 129/SvEv mice lacking the endothelin-A (ET(A))-receptor to determine whether endothelin-1 (ET-1), acting as a messenger for oxygen constriction, is responsible for closure of the ductus arteriosus at birth. The isolated ductus from ET(A) -/- fetuses, unlike that from ET(A) +/+ littermates, contracted marginally to oxygen and ET-1 but responded to a thromboxane analog. In vivo, reduction in ductus lumen was equally pronounced in tracheotomized ET(A) -/- and ET(A) +/+ newborns. Conversely, no such vessel narrowing was seen in hyperoxic ET(A), -/- fetuses, although it occurred in ET(A) +/+ littermates. Notwithstanding the uneven behaviour of the ductus in vitro and in vivo, no ET(A) genotype-related difference was noted in the morphology of the vessel on both light and electron microscopy. We conclude that ET-1 mediates the ductus constriction to oxygen. Without ET-1, however, the vessel still closes postnatally probably as a result of the withdrawal of the relaxing influence of prostaglandin E2 (PGE2).

Contractile and relaxing mechanisms in pulmonary resistance arteries of the preterm fetal lamb

Isolated pulmonary resistance arteries from term fetal lambs have nitric oxide (NO)- and prostaglandin-mediated relaxing mechanisms which are activated when PO(2) is raised from fetal to neonatal levels. The same vessels contract under hypoxia, and the contraction has been ascribed to endothelin-1 (ET-1). We have now studied these vasoeffector mechanisms before term (0.7 and 0.65 gestation) with the objective of determining whether their activity correlates with the development of susceptibility to oxygen changes. Experiments were carried out at neonatal PO(2), when expectedly relaxing mechanisms are maximally expressed, or under hypoxia. At either fetal age, the NO synthesis inhibitor, N(G)-nitro-L-arginine methyl ester (100 microM), had no effect on basal tone, while indomethacin (2.8 microM) was a weak constrictor. Premature arteries did not contract when first exposed to hypoxia, but they responded marginally to a second exposure. The same arteries contracted strongly to a thromboxane A(2) analogue (ONO-11113, 0.1 microM) and ET-1 (10 nM), while their contraction to activating solution (5 mM Ca(2+) in K(+)-Krebs solution) was small and variable. At 0.7 gestation, bradykinin (0.1-100 nM), acetylcholine (0.01-10 microM), and sodium nitroprusside (0.1 nM to 10 microM) dose-dependently relaxed arteries precontracted with ONO-11113. Conversely, at 0.65 gestation the relaxation to bradykinin and acetylcholine was not dose-dependent and tended to be weaker. We conclude that preterm pulmonary arteries have viable effector mechanisms for contraction and relaxation. However, the capability for these mechanisms to be activated by PO(2) changes is markedly curtailed.

Autonomic nervous influence of the female guinea-pig urinary bladder during the oestrus cycle

The mammalian urinary bladder receives dual innervation. The excitatory innervation is considered to be partly cholinergic and partly mediated via NANC-receptors. Several (co-)transmitters have been suggested. The adrenergic inhibitory innervation is mediated via alpha- and beta-receptors. Female sex hormones could change autonomic influence of urogenital organs. It was considered to be of interest to characterize the spontaneous and nerve stimulation-induced muscular activity in the urinary bladder of the female guinea-pig during the oestrus cycle. Both the spontaneous activity and nerve-induced activity varied according to the hormonal status of the animal. An alpha-adrenergic inhibitory influence was identified. It was further confirmed that the excitatory innervation could not be blocked by the cholinergic antagonist scopolamine, while alpha-beta-methylene ATP partly inhibited nerve stimulation-induced smooth muscle response, most prominent at cycle day 6. Indomethacin did not impair spontaneous activity or nerve stimulation-induced activity. Nitric oxide reduced nerve stimulation-induced responses on cycle day 12. Imperative urinary bladder contractions are reported to diminish after oestrogen use and in the female a hormonal effect of the nervous influence on the urinary bladder smooth muscle is suggested.

Endothelin-induced contractions in human placental blood vessels are enhanced in intrauterine growth retardation, and modulated by agents that regulate levels of intracellular calcium

Endothelin-1 (ET-1) is a strongly vasoactive polypeptide that may be involved in the regulation of the uteroplacental blood flow. In the present study we have examined the contractile response to ET-1 in human placental arteries in the presence of several agents that interfere with storage of intracellular calcium, e.g. caffeine, ryanodine and thapsigargin. We have also compared the contractile response to ET-1 in normal pregnancies with that of patients with foetal intrauterine growth retardation (IUGR), a condition with reduced uteroplacental blood flow. We found that the response to ET-1 in the placental arteries from women with normal pregnancies was reduced by 20% in the absence of extracellular calcium. Caffeine relaxed the basal tone of the vessels and reduced the contractile response to ET-1 by 51%. Nifedipine in addition to caffeine resulted in a reduction of 70%. Ryanodine also reduced the tone. Thapsigargin had no effect on the placental arteries at lower concentrations, but gave a progressive and slow contraction at 10(-6) M. The ET-1 induced contraction in placental arteries from IUGR patients was 67% more potent than in placental arteries from women with normal pregnancies, 129% as compared with 77% of the maximal K(+)-induced contraction. We conclude that the ET-1-induced contractile response in the human placental artery is dependent on influx of extracellular calcium as well as mobilization of calcium from intracellular stores. An increased sensitivity to ET-1 in placental arteries may contribute to the reduced uteroplacental blood flow in intrauterine growth retardation.

Effects of endothelin, calcium channel blockade and EDRF inhibition on the contractility of human uteroplacental arteries

In order to examine the possibility that endothelin might be important in the regulation of placental blood flow, human uteroplacental vessels were superfused in vitro to study the contractile effect of endothelin as compared with a known strong contractor of placental blood vessels, serotonin (5-HT). The contractile responses were compared in the presence and absence of calcium channel blocking agents, as well as in the presence of L-NMA, an inhibitor of EDRF/nitric oxide. Endothelin (ET, 10(-10)-10(-6) M) and 5-HT (10(-8)-10(-4) M) induced contractions in the vessels. Maximal contractions in the presence of endothelin were elicited at 10(-7) M, whereas 5-HT elicited maximal contractions at 10(-5) M. At 10(-7) M, ET was more potent than 5-HT. The calcium-channel blocking agents nifedipine, diltiazem and NiCl2 relaxed the vessels by 5-15% from baseline. The contractile response to ET in the presence of nifedipine or diltiazem was reduced by 55 and 67%, respectively. The response of 5-HT in the presence of nifedipine was reduced by 58%. The contractile response to 5-HT as well as ET in the presence of both nifedipine and NiCl2 was not significantly lower than in the presence of nifedipine only. The EDRF-inhibiting agent L-NMA caused a small contractile response at concentrations of 10(-6)-10(-5) M. ET as well as 5-HT added after pretreatment with L-NMA produced a larger contractile response than ET or 5-HT alone. The results show that ET has a strong contractile effect on placental blood vessels at concentrations likely to occur during labor and delivery. The mechanism whereby ET as well as 5-HT contracts placental vessel smooth muscle appears to partly involve nifedipine- and diltiazem-sensitive calcium channels, but almost half of the response depends on mobilization of calcium through other means.

Endothelin contracts human uterine myometrium by a partly dihydropyridine-sensitive mechanism

The effect of endothelin (ET), a recently discovered 21-amino-acid polypeptide with powerful vasoconstrictor properties, was examined on human uterine myometrial strips in vitro. ET dose-dependently (10(-11)-10(-7) M) increased the contractile force (monitored as contraction amplitude) of the myometrium with significant effects at 10(-8) and 10(-7) M. ET (10(-8) M and up) also increased the basal tone of the myometrium. The calcium channel blocking agents nifedipine (10(-7) M) and diltiazem (10(-6) M) both inhibited the spontaneous tonic contractions of the myometrium. When ET was given in the presence of nifedipine, the tonic contractions were further inhibited, whereas the ET-induced increase in basal tone remained. The same result was obtained with diltiazem (10(-6) M). The results indicate that the contractility of human myometrium may be modulated by ET, and that the effects of ET on the human myometrium are only partly mediated by dihydropyridine-sensitive calcium channels.

Clearance of osteocalcin by peritoneal dialysis in children with end-stage renal disease

Osteocalcin is a bone-specific protein whose concentration in blood is a direct reflection of bone turnover. In chronic renal failure, circulating osteocalcin is elevated. This elevation is due to decreased renal clearance and, in some patients, increased bone turnover secondary to renal osteodystrophy. In children receiving continuous ambulatory peritoneal dialysis, mean serum osteocalcin concentrations are substantially lower than in similar patients on hemodyalysis (1). This difference may be due to clearance of the protein by the peritoneal membrane. To test this possibility we examined osteocalcin in 16 infants and adolescents undergoing continuous ambulatory peritoneal dialysis with two commercially available glucose-based dialysis solutions (2.5 and 4.25% Dianeal). Mass transfer of osteocalcin over 5-h dialysis exchange periods was -18.9 +/- 2.8 and -28.4 +/- 7.8 micrograms for the low and high glucose solutions, respectively. Serum levels fell over the course of single exchange periods in concert with increasing dialysate concentrations. There were significant correlations between initial blood concentrations of osteocalcin and the total amount of osteocalcin transferred (r = 0.609 and 0.642 for the high and low glucose solutions, respectively, p less than 0.05). There were also strong correlations between the mass transfers of osteocalcin and those of creatinine (p less than 0.05) and total protein (p less than 0.01) with the 4.25% glucose exchange. The relationships were weaker with the 2.5% glucose exchange. Fractionation of serum revealed a single immunoreactive peak eluting coincident with intact osteocalcin, but two or three immunoreactive peaks were identified in matching dialysate samples, suggesting that both intact osteocalcin and circulating fragments are transferred by the peritoneal membrane.(ABSTRACT TRUNCATED AT 250 WORDS)