De novo FRMD5 Missense Variants in Patients with Childhood-Onset Ataxia, Prominent Nystagmus, and Seizures

BACKGROUND

FRMD5 variants were recently identified in patients with developmental delay, ataxia, and eye movement abnormalities.

OBJECTIVES

We describe 2 patients presenting with childhood-onset ataxia, nystagmus, and seizures carrying pathogenic de novo FRMD5 variants. Weighted gene co-expression network analysis (WGCNA) was performed to gain insights into the function of FRMD5 in the brain.

METHODS

Trio-based whole-exome sequencing was performed in both patients, and CoExp web tool was used to conduct WGCNA.

RESULTS

Both patients presented with developmental delay, childhood-onset ataxia, nystagmus, and seizures. Previously unreported findings were diffuse choreoathetosis and dystonia of the hands (patient 1) and areas of abnormal magnetic resonance imaging signal in the white matter (patient 2). WGCNA showed that FRMD5 belongs to gene networks involved in neurodevelopment and oligodendrocyte function.

CONCLUSIONS

We expanded the phenotype of FRMD5-related disease and shed light on its role in brain function and development. We recommend including FRMD5 in the genetic workup of childhood-onset ataxia and nystagmus. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Pancreatic adenocarcinoma patients with localised chronic severe pancreatitis show an increased number of single beta cells, without alterations in fractional insulin area

AIMS/HYPOTHESIS

Recent histological analysis of pancreases obtained from patients with long-standing type 1 diabetes identified chronic islet inflammation and limited evidence suggestive of beta cell replication. Studies in rodent models also suggest that beta cell replication can be induced by certain inflammatory cytokines and by gastrin. We therefore tested the hypothesis that beta cell replication is observed in non-autoimmune human pancreatic disorders in which localised inflammation or elevated gastrin levels are present.

METHODS

Resected operative pancreatic specimens were obtained from patients diagnosed with primary adenocarcinoma (with or without chronic severe pancreatitis) or gastrinoma. Additional pancreatic tissue was obtained from autopsy control patients. Immunohistochemistry was used to assess fractional insulin area, beta cell number and replication rate and differentiation factors relevant to beta cell development.

RESULTS

Fractional insulin area was similar among groups. Patients with pancreatic adenocarcinoma and localised chronic severe pancreatitis displayed significant increases in the number of single beta cells, as well as increased beta cell replication rate and levels of neurogenic differentiation 1 in islets. Patients with gastrinoma demonstrated significant increases in the number of single beta cells, but the beta cell replication rate and islet differentiation factor levels were similar to those in the control group.

CONCLUSIONS/INTERPRETATION

These findings indicate that chronic severe pancreatic inflammation can be associated with significant effects on beta cell number or replication rate, depending on the distribution of the cells. This information may prove useful for attempts seeking to design therapies aimed at inducing beta cell replication as a means of reversing diabetes.

Site of action of GABA(B) receptor for vagal motor control of the lower esophageal sphincter in ferrets and rats

BACKGROUND & AIMS

Stimulation of gamma-aminobutyric acid B metabotropic receptors (GBRs) by baclofen reduces the incidence of transient lower esophageal sphincter (LES) relaxations. The GBR effect may be a result of a central site of action in the dorsal vagal complex, where upper gastrointestinal vagal reflexes are integrated. Therefore, we first localized GBR immunostaining in the dorsal vagal complex. Next, we tested the hypothesis that baclofen modulates LES motor tone via GBR expressed by vagal efferent neurons.

METHODS

An antibody against the human GBR1b isoform was characterized and used for immunocytochemistry in rats and ferrets. Functional studies involved microinjection of L-glutamate into the caudal dorsal motor nucleus of the vagus to evoke an LES relaxation in decerebrate unanesthetized ferrets.

RESULTS

In both species, GBR1b was expressed in preganglionic motor neurons and, in ferrets, the receptor was highly expressed in identified LES-projecting preganglionic neurons. GBR1b immunostaining was also pronounced in the subnucleus centralis of the nucleus tractus solitarius. This distribution implicates GBR in control of the esophageal phase of swallowing at the level of the central program generator. In functional studies, centrally evoked LES relaxation (-73% +/- 8% mm Hg) was significantly attenuated after 7 micromol/kg intravenous baclofen (-37% +/- 10%; N = 5).

CONCLUSIONS

These data all suggest that GBR agonists inhibit LES relaxation via a site of action associated with vagal motor outflow to the LES.

Quality beyond compliance

The service sector within the biopharmaceutical industry has experienced phenomenal growth over the past decade. In the highly regulated Good Laboratory Practices environment, the need for timely, high-quality service, accurate results, and on-time deliverables becomes paramount for the success and profitability of biopharmaceutical companies. The quality assurance process is a vital component of this drug product-development cycle and ensures compliance to the highest domestic and international regulatory standards. Quality-assurance professionals historically have held the role of independent auditors of the processes, who certify that results meet current standards of practice. Covance, a contract research organization that includes Good Laboratory Practices laboratories, reorganized and expanded the functional responsibilities of its quality assurance team in 1997. Auditors and quality assurance professionals have assumed roles beyond traditional compliance auditing and are forging new leadership and mentoring roles as process-improvement specialists. The results have been tangible, measurable benefits for clients and the Covance organization. This article provides an overview of this cultural change and the processes put in place to improve efficiency, productivity, and customer and employee satisfaction.

Effect of postmenopausal hormone replacement therapy on dental outcomes: systematic review of the literature and pharmacoeconomic analysis

A systematic review and economic analysis of clinical trials evaluating the effect of hormone replacement therapy (HRT) on dental outcomes in postmenopausal women were conducted. Twenty published studies involving more than 13,735 postmenopausal women were summarized and analyzed. In prospective studies, the effect of HRT on osteoporosis (OP) has been well documented. The effect of OP on mandibular bone density has also been examined in some observational studies. Few studies, however, have examined the effect of HRT directly on mandibular bone density or on dental outcomes. From these studies, the effect of HRT on costs of dental treatment and prophylaxis was estimated directly and indirectly. It was determined that HRT use was associated with reduction in adverse dental outcomes and the associated costs of dental care. Annualized excess cost in a cohort of 1,000 untreated women averaged $100,000. From this analysis, it is clear that postmenopausal women with OP who do not receive HRT have a greater incidence of adverse dental outcomes and higher dental care costs than those who do.

Blood redistribution and circulatory responses to submaximal arm exercise in persons with spinal cord injury

The purpose of this study was to evaluate responses to submaximal arm exercise (20%, 40%, and 60% of peak power output) using four conditions to support the circulatory redistribution in persons with spinal cord injury (SCI). Five males with tetraplegia (TP) and four males with paraplegia (PR) exercised 1) sitting, 2) supine, and 3) sitting with the addition of a) an anti-gravity suit (anti-G), b) elastic stockings and abdominal binder, and c) functional electrical stimulation of the leg muscles. Compared to sitting, the following significant changes were observed: in the supine position, heart rate (HR) decreased (PR: 104 vs 118 b/min, TP: 76 vs 92 b/min) and stroke volume (SV) increased (PR: 132 vs 116 ml, TP: 96 vs 83 ml). The anti-G suit induced a decrease in heart rate (PR: 104 vs 118 b/min, TP: 87 vs 92 b/min) and a decrease in oxygen uptake (VO2) in PR. Stockings only affected TP, i.e. a decrease in heart rate with 5 b/min and an increase in stroke volume with 13 ml/beat. Functional electrical stimulation produced an increase in VO2 (PR: 1.00 vs 0.95 l/min, TP: 0.68 vs 0.53 l/min) and a rise in stroke volume in TP. Results indicate that the methods employed to support the circulatory redistribution have different working mechanisms and, in addition, that the effects are different for TP and PR probably because of differences in active muscle mass, sympathetic impairment and blood pressure values.

Limits to maximal performance in individuals with spinal cord injury

The purpose of this study was to examine the effect of four conditions that might improve oxygen transport and/or utilization during maximal exercise performance in individuals with spinal cord injury (SCI). Five males with tetraplegia (TP) and four males with paraplegia (PR) performed maximal arm cranking exercise in the following positions: 1) sitting; 2) supine; and 3) sitting with the addition of a) anti-gravity suit (anit-G), b) elastic stockings and abdominal binder, and c) functional electrical stimulation (FES) of the paralysed leg muscles. Peak power output (PO peak), peak oxygen uptake (VO2peak), peak heart rate (HR peak) and maximal systolic blood pressure were significantly lower in TP compared to PR for all conditions. A significant decrease in HR peak for PR, and a significant increase in VO2peak/kg for TP was seen during the supine compared to sitting condition. Respiratory exchange ratio (R) decreased significantly during the FES compared to the sitting condition in TP. No other changes were observed for any of the other conditions in either group. Improvements in central circulation previously reported during submaximal exercise for these four conditions did not result in a concomitant rise in maximal exercise performance. The results of this study suggest that the limitation in VO2peak for individuals with SCI is located peripherally (small active muscle mass) rather than centrally (heart or lungs).

The relationship of homophobia to intimacy in heterosexual men

Interpersonal intimacy is more difficult to achieve for American men than women. Research has shown that men disclose less, have fewer close friendships, and are viewed by their wives as low in intimacy. Among the barriers to intimacy among men, Tognoli (1980) suggested that homophobia is the most powerful. The present study tested this idea by asking men to disclose a personal secret to either a male confidant, a female confidante, or by writing the secret. It was expected that the presence of a male confidant would stimulate homophobic feelings and inhibit disclosure, while the other two conditions would result in more personal disclosure. A correlation between intimacy of disclosure and level of homophobia was also expected. Subjects were 75 heterosexual men, 31 to 50 years of age, randomly assigned to one of the three conditions. They also completed the Miller Social Intimacy Scale, the Jourard Self-Disclosure Questionnaire, the Index of Homophobia, and the Marlowe-Crowne Social Desirability Scale. Results showed that homophobia was inversely related to level of social intimacy. There was some indication that homophobia does relate to less intimate disclosure to other males. Thus this study found some support for the idea that homophobia is an obstacle to intimacy for men.

Isolation of black creek canal virus, a new hantavirus from Sigmodon hispidus in Florida

Numerous rodents were trapped for serologic and virologic studies following the identification of a hantavirus pulmonary syndrome (HPS) case in Dade County, Florida. Cotton rats (Sigmodon hispidus) were the most frequently capture rodent and displayed the highest seroprevalence to a variety of hantavirus antigens. Hantavirus genome RNA was detected in all the seropositive cotton rats tested, using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. A virus was isolated from tissues of two seropositive cotton rats by cultivation of lung and spleen homogenates on Vero E6 cells. Nucleotide sequence information obtained by direct RT-PCR and the serologic relationships of this virus with the other hantaviruses indicate that this virus, Black Creek Canal virus, represents a new hantavirus distinct from the previously known serotypes.

Isolation of the causative agent of hantavirus pulmonary syndrome

Investigation of a recent outbreak of acute respiratory illness in the southwestern United States resulted in the recognition of a new disease, hantavirus pulmonary syndrome (HPS) with high mortality. Different animals and cell lines were used in attempts to isolate the causative agent. A previously unknown hantavirus was passaged in laboratory-bred deer mice, recovered from lung tissues of a deer mouse, Peromyscus maniculatus, and propagated in the E6 clone of Vero cells. Virus antigen was readily detected in the infected cells by an indirect immunofluorescence assay, using convalescent-phase sera from HPS patients. By electron microscopy, the virus was shown to have the typical morphologic features of members of the genus Hantavirus, family Bunyaviridae. Virus sequences corresponded to those previously detected by a nested reverse transcriptase-polymerase chain reaction assay of hantavirus-infected specimens from rodents and humans. This newly recognized virus, the etiologic agent of HPS, has been tentatively named Muerto Canyon virus.

Biomechanical comparison of methods of fixation of a midshaft osteotomy of the humerus

Using paired humeri with a midshaft osteotomy, the biomechanical stiffness of four intramedullary internal fixation devices were compared with each other, a dynamic compression plate, and with the intact bone. In posterior and lateral bending and in torsion, flexible intramedullary pin fixed humeri (Enders and Hackethal) performed similarly and were less stiff than intact specimens were. Interlocking intermedullary nail constructs (Russell-Taylor and Seidel) also tested similarly to each other, and were stiffer than the flexible pins in all bending tests. Compared with the intact humerus, interlocking nails were stiffer in torsion, but in bending they more closely simulated the stiffness of the bone.

Studies on the assembly of large subunits of ribulose bisphosphate carboxylase in isolated pea chloroplasts

Ribulose bisphosphate carboxylase consists of cytoplasmically synthesized "small" subunits and chloroplast-synthesized "large" subunits. Large subunits of ribulose bisphosphate carboxylase synthesized in vivo or in organello can be recovered from intact chloroplasts in the form of two different complexes with sedimentation coefficients of 7S and 29S. About one-third to one-half of the large subunits synthesized in isolated chloroplasts are found in the 7S complex, the remainder being found in the 29S complex. Upon prolonged illumination of the chloroplasts, newly synthesized large subunits accumulate in the 18S ribulose bisphosphate carboxylase molecule and disappear from both the 7S and the 29S large subunit complexes. The 29S complex undergoes an in vitro dissociation reaction and is not as stable as ribulose bisphosphate carboxylase. The data indicate that (a) the 7S large subunit complex is a chloroplast product, the (b) the 29S large subunit complex is labeled in vivo, that (c) each of these two complexes can account quantitatively for all the large subunits assembled into RuBPCase in organello, and that (d) excess large subunits are degraded in chloroplasts.

Antibodies to ribonucleic acid in systemic lupus erythematosus

Sera of 16 of 89 patients with systemic lupus erythematosus contained precipitating antibodies to RNA. These antibodies were found infrequently in patients with rheumatoid arthritis and Sjögren's syndrome, and not at all in patients with juvenile rheumatoid arthritis, myeloma, nor in normal individuals. These studies present evidence for the presence of antibodies to double-stranded RNA (both synthetic and viral). The fact that mammalian RNA's are probably single-stranded nucleotides suggests that these anti-RNA antibodies are directed primarily to a foreign, double-stranded RNA antigen.