Intra-arterial administration of carboplatin and the blood brain barrier permeabilizing agent,RMP-7: A toxicologic evaluation in swine

RMP-7 is a bradykinin B2 receptor agonist shown to permeabilize the blood-brain barrier, especially that associated with brain tumors, when administered via both intracarotid and intravenous routes. Both routes of administration are currently being tested in human trials in combination with the chemotherapeutic agent carboplatin as therapy for gliomas. As an essential prerequisite to the initial intracarotid clinical trials, the potential neurotoxicity of intra-arterial administration of RMP-7 (at a high or low dose), alone and in combination with carboplatin, was assessed in anesthetized Red Duroc swine. Five treatment groups were evaluated with each pig receiving a series of alternating, intra-arterial infusions of RMP-7 (or saline) followed by carboplatin (or saline), as follows: (1) vehicle control: saline/saline; (2) carboplatin only control: saline/carboplatin (50 mg total); (3) RMP-7 only control: RMP-7 (750 ng/kg)/saline; (4) low dose combination: RMP-7 (75 ng/kg)/carboplatin (50 mg total); and (5) high dose combination: RMP-7 (750 ng/kg)/carboplatin (50 mg total). For each subject, one of the alternating dosing sequences (above) was repeated four times during a single dosing session which lasted approximately 40 minutes. Assessments during the in-life phase of the study in the pre- and post-treatment periods consisted of heart rate, arterial blood pressure (systolic, diastolic, and mean), blood gases, body weight, general clinical observations (including evaluation for neurological deficit) and clinical pathology (including a comprehensive battery of standard blood coagulation, hematological and serum chemistry tests). In addition, during the time of treatment, heart rate and arterial blood pressure were monitored. The animals were terminated two weeks after dosing and the brain and rete mirabile (distal to site of infusion) were evaluated for gross and histopathological abnormalities. The histopathology analysis included a reader-blinded analysis using low and high power light microscopic examination of both H&E and Kluver-Berrera stained sections through several key cortical and subcortical brain regions. Transient decreases in arterial blood pressure (mean of 10–25 mmHg) were observed in both groups receiving the high dose of RMP-7 (i.e., 750 ng/kg). No other side effects attributable to RMP-7 and/or carboplatin were observed, and clinical observations revealed no evidence of neurologic deficits. Post-mortem examination revealed no evidence of CNS or cerebral vascular pathology attributable to carboplatin and RMP-7. This study demonstrates that intracarotid administration of the maximum tolerated dose of RMP-7 (750 ng/kg) alone, or in combination with carboplatin (50 mg) is not accompanied by any serious adverse effect, apparent cerebrovascular abnormality or neuropathologic consequence and offers further evidence for the safety of this novel therapeutic approach for enhancing delivery of chemotherapeutics to brain tumors.     

Severe bronchopulmonary dysplasia increases risk for later neurological and motor sequelae in preterm survivors

Preterm children who develop severe chronic lung disease may be developmentally compromised by exposure to hypoxic episodes. This study aims to determine if children with severe bronchopulmonary dysplasia (BPD) who required home oxygen therapy were at greater risk for neurological and motor deficits at school age than preterm peers without BPD. This study evaluated 27 subjects with BPD and 27 preterm control infants matched for gestational age, birthweight, sex, and year of birth at a mean age of 9.9 years (2.0 SD) using standardized neuromotor outcome measures. Pair-matched comparisons and regression analyses were used to determine if subjects with BPD were at increased risk for neuromotor sequelae. Neurological abnormalities, including subtle neurological signs, cerebral palsy, microcephaly, and behavioral difficulties were highly prevalent in the BPD group (71% compared with 19% in control group, P<0.005). Over half the BPD cohort had difficulties in gross and/or fine motor skills. There were significant differences in postural stability between groups. Duration of hospitalization and home oxygen treatment, and decreased lung function at school age, markers of severity of illness, correlated with motor outcomes. The findings underline the importance of preventing the cardiorespiratory complications associated with chronic lung disease to minimize disability in preterm children. For children with severe BPD, better recognition and subsequent remediation of neuromotor impairments that manifest at school age may help maximize their functional potential.     

Effects of hindlimb unloading on neuromuscular development of neonatal rats

We hypothesized that hindlimb suspension unloading of 8-day-old neonatal rats would disrupt the normal development of muscle fiber types and the motor innervation of the antigravity (weightbearing) soleus muscles but not extensor digitorum longus (EDL) muscles. Five rats were suspended 4.5 h and returned 1.5 h to the dam for nursing on a 24 h cycle for 9 days. To control for isolation from the dam, the remaining five littermates were removed on the same schedule but not suspended. Another litter of 10 rats housed in the same room provided a vivarium control. Fibers were typed by myofibrillar ATPase histochemistry and immunostaining for embryonic, slow, fast IIA and fast IIB isomyosins. The percentage of multiple innervation and the complexity of singly-innervated motor terminal endings were assessed in silver/cholinesterase stained sections. Unique to the soleus, unloading accelerated production of fast IIA myosin, delayed expression of slow myosin and retarded increases in standardized muscle weight and fiber size. Loss of multiple innervation was not delayed. However, fewer than normal motor nerve endings achieved complexity. Suspended rats continued unloaded hindlimb movements. These findings suggest that motor neurons resolve multiple innervation through nerve impulse activity, whereas the postsynaptic element (muscle fiber) controls endplate size, which regulates motor terminal arborization. Unexpectedly, in the EDL of unloaded rats, transition from embryonic to fast myosin expression was retarded. Suspension-related foot drop, which stretches and chronically loads EDL, may have prevented fast fiber differentiation. These results demonstrate that neuromuscular development of both weightbearing and non-weightbearing muscles in rats is dependent upon and modulated by hindlimb loading.     

The effects of sucrose on stability of human brain natriuretic peptide [hBNP (1–32)] and human parathyroid hormone [hPTH (1–34)]

Abstract: Although the effect of sucrose on the physical stability of proteins has been well documented, its impact on their chemical stability is largely unknown. The aim of this study was to investigate the potential effects of sucrose on the structural conformation of human brain natriuretic peptide [hBNP (1–32)] and the synthetic human parathyroid hormone [hPTH (1–34)], and link these effects to chemical degradation pathways of these peptides. The stability of hBNP (1–32) and hPTH (1–34) was studied at pH 5.5. Aggregation was monitored using size exclusion high‐performance liquid chromatography (SE‐HPLC), whereas oxidation and deamidation products were measured by reversed phase (RP) HPLC. Fourier transform infrared (FT‐IR) spectroscopy was used to study the peptides’ conformation. Sucrose retarded aggregation, deamidation, and oxidation of hBNP (1–32) and hPTH (1–34), with a maximum effect at relatively high concentrations (as much as 1 m ). FT‐IR spectroscopy indicated that sucrose maintained the native conformation of hBNP (1–32) and induced small conformation changes in the hPTH (1–34) structure. Sucrose enhanced the stability of hBNP (1–32) and hPTH (1–34) in liquid formulations. The stabilizing effect of sucrose was due to a large extent to retardation of oxidation and deamidation of hBNP (1–32) and hPTH (1–34).     

Comparison of in vivo and in vitro percutaneous absorption of T-2 toxin in guinea pigs

The fate and distribution of T-2 were examined in 6 guinea pigs. T-2 (1.2 micrograms/cm2), in methanol or DMSO, was painted onto the shaved backs of guinea pigs, a screen barrier was applied, urine and feces were collected daily and the guinea pigs were killed after 48 hr. Disks of skin (lateral to the in vivo site of application) were excised from the guinea pigs and used for in vitro penetration studies with static diffusion cells. Skin excised from 6 additional guinea pigs was used for penetration studies with flow-through diffusion cells. For in vitro studies, T-2 dissolved in methanol or DMSO was applied to the epidermal surfaces and the appearance of penetrant in receptor fluid bathing the dermal surfaces was monitored for 48 hr. Metabolism of T-2 was measured by using thin layer radiochromatography to identify metabolites. In the in vivo study, mean cutaneous absorption (n = 3) after 48 hr (expressed as per cent dose) was 22.5 and 51.9 for the methanol and DMSO groups, respectively. In vitro cutaneous penetration for static diffusion cells was 3.9 and 38.4 for the methanol and DMSO groups. For flow-through diffusion cells, mean penetration (n = 9) was 14.6 and 42.6 for the methanol and DMSO groups. Urinary metabolites of T-2 were T-2 triol, 3' OH-HT-2, T-2 tetraol, the glucuronide conjugate of HT-2 and several more polar metabolites. The main metabolite of T-2 in the receptor fluid bathing the dermal surfaces of excised skin was HT-2.     

Association of social determinants of health with late diagnosis and survival of patients with pancreatic cancer

BackgroundPancreatic cancer disparities have been described. However, it is unknown if they contribute to a late diagnosis and survival of patients with metastatic disease. Identifying their role is important as it will open the door for interventions. We hypothesize that social determinants of health (SDH) such as income, education, race, and insurance status impact (I) stage of diagnosis of PC (Stage IV vs. other stages), and (II) overall survival (OS) in Stage IV patients.MethodsUsing the National Cancer Database, we evaluated a primary outcome of diagnosis of Stage IV PC and a secondary outcome of OS. Primary predictors included race, income, education, and insurance. Covariates included age, sex and Charlson-Deyo comorbidity score. Univariate, multivariable logistic regression models evaluated risk of a late diagnosis. Univariate, multivariable Cox proportional hazards model examined OS. 95% confidence intervals were used.Results230,877 patients were included, median age of 68 years (SD 12.1). In univariate analysis, a better education, higher income, and insurance decreased the odds of Stage IV PC, while Black race increased it. In multivariable analysis, education [>93% high-school completion (HSC) vs. <82.4%, OR 0.96 (0.93–0.99)] and insurance [private vs. no, OR 0.72 (0.67–0.74)] significantly decreased the risk of a late diagnosis, whereas Black race increased the odds [vs. White, OR 1.09 (1.07–1.12)]. In univariate Cox analysis, having a higher income, insurance and better education improved OS, while Black race worsened it. In multivariable Cox, higher income [>$63,333 (vs. <$40,277), HR 0.87 (0.85–0.89)] and insurance [private vs. no, HR 0.77 (0.74–0.79)] improved OS.ConclusionsSDH impacted the continuum of care for patients with advanced pancreatic cancer, including stage at diagnosis and overall survival.     

Cochlear implants for pre-lingually profoundly deaf adults

Introduction: Increasing numbers of pre-lingually profoundly deaf adults are seeking a cochlear implant (CI). Pre- and post-operative outcomes are presented on 20 of these patients.

Results: An Adult Pre-Lingually Profoundly Deaf Implant Profile (APDIP) weighted the pre-operative level of concern about potential CI benefit. Results indicated no group mean post-operative open-set improvement. However CUNY sentence testing (auditory plus lip-reading cues) revealed improved performance with a CI. Twelve out of 20 patients used their CIs for more than 10 hours per day, suggesting good usage. Moreover, hours of usage were positively associated with measured benefit on CUNY sentences in the lip-reading plus sound via CI condition. There was no apparent relationship between pre-operative level of concern and post-operative CI performance or hours of processor use.

Conclusion: Results suggest implantation is beneficial and effective in this group.     

Congenital pancreatic hypoplasia: a syndrome of exocrine and endocrine pancreatic insufficiency

We describe two brothers with small size at birth, early-onset insulin-dependent diabetes, and pancreatic exocrine insufficiency. In contrast to the findings in pancreatic aplasia, their serum C-peptide and glucagon levels were measurable. These findings, in concert with their clinical courses, are consistent with the diagnosis of congenital pancreatic hypoplasia.     

The effects of thiosemicarbazide on development in the wood frog, Rana sylvatica. II. Critical exposure length and age sensitivity

Wood frog (Rana sylvatica) tadpoles were exposed to 50 mg thiosemicarbazide (TSC)/liter water for varying lengths of time and at different developmental stages. Short exposure periods (3 and 6 hr) resulted in no visible deformities. Exposure periods of 12 or more hr caused slight to severe abnormalities, with a direct relationship between length of exposure and degree of deformity. Tadpoles exposed to TSC from posthatching Days 24-30 were more seriously affected than were tadpoles exposed at an older age.