Erratum: Altered gene expression linked to germline dysfunction following exposure to DEET

[This corrects the article DOI: 10.1016/j.isci.2023.108699.].

Altered gene expression linked to germline dysfunction following exposure of Caenorhabditis elegans to DEET

N,N-diethyl-meta-toluamide (DEET) is a commonly used synthetic insect repellent. Although the neurological effects of DEET have been widely investigated, its effects on the germline are less understood. Here, we show that exposure of the nematode Caenorhabditis elegans, which is highly predictive of mammalian reprotoxicity, resulting in internal DEET levels within the range detected in human biological samples, causes activation of p53/CEP-1-dependent germ cell apoptosis, altered meiotic recombination, chromosome abnormalities, and missegregation. RNA-sequencing analysis links DEET-induced alterations in the expression of genes related to redox processes and chromatin structure to reduced mitochondrial function, impaired DNA double-strand break repair progression, and defects during early embryogenesis. We propose that Caenorhabditis elegans exposure to DEET interferes with gene expression, leading to increased oxidative stress and altered chromatin structure, resulting in germline effects that pose a risk to reproductive health.

Exposure to phthalates: germline dysfunction and aneuploidy

Epidemiological studies continue to reveal the enduring impact of exposures to environmental chemicals on human physiology, including our reproductive health. Phthalates, a well characterized class of endocrine disrupting chemicals and commonly utilized plasticizers, are among one of the many toxicants ubiquitously present in our environment. Phthalate exposure has been linked to increases in the rate of human aneuploidy, a phenomenon that is detected in 0.3% of livebirths resulting in genetic disorders including trisomy 21, approximately 4% of stillbirths, and over 35% of miscarriages. Here we review recent epidemiological and experimental studies that have examined the role that phthalates play in germline dysfunction, including increases in apoptosis, oxidative stress, DNA damage, and impaired genomic integrity, resulting in aneuploidy. We will further discuss subject variability, as it relates to diet and polymorphisms, and the sexual dimorphic effects of phthalate exposure, as it relates to sex-specific targets. Lastly, we discuss some of the conserved effects of phthalate exposure across humans, mammalian models and nonmammalian model organisms, highlighting the importance of using model organisms to our advantage for chemical risk assessment and unveiling potential mechanisms that underlie phthalate-induced reproductive health issues across species.

Lumbar paraspinal muscle transverse area and symmetry in dogs with and without degenerative lumbosacral stenosis

OBJECTIVES

To investigate whether dogs with degenerative lumbosacral stenosis have decreased lumbar paraspinal muscle transverse area and symmetry compared with control dogs.

MATERIALS AND METHODS

Retrospective cross-sectional study comparing muscles in transverse T2-weighted magnetic resonance images for nine dogs with and nine dogs without degenerative -lumbosacral stenosis. Mean transverse area was measured for the lumbar multifidus and sacrocaudalis dorsalis lateralis muscles bilaterally and the L7 vertebral body at the level of the caudal endplate. Transverse areas of both muscle groups relative to L7 and asymmetry indices were compared between study populations using independent t tests.

RESULTS

Mean muscle-to-L7 transverse area ratios were significantly smaller in the degenerative lumbosacral stenosis group compared with those in the control group in both lumbar multifidus (0·84 ±0·26 versus 1·09 ±0·25; P=0·027) and sacrocaudalis dorsalis lateralis (0·5 ±0·15 versus 0·68 ±0·12; P=0·005) muscles. Mean asymmetry indices were higher for both muscles in the group with degenerative lumbosacral stenosis than in the control group, but highly variable and the difference was not statistically significant.

CLINICAL SIGNIFICANCE

These findings suggest that dogs with degenerative lumbosacral stenosis have decreased lumbar paraspinal muscle mass that may be a cause or consequence of the -syndrome. Understanding altered paraspinal muscle characteristics may improve understanding of the -pathophysiology and management options for degenerative lumbosacral stenosis.

Targeting of Pseudomonas aeruginosa in the bloodstream with bispecific monoclonal antibodies

We examined the ability of a bispecific mAb reagent, consisting of a mAb specific for the primate erythrocyte complement receptor cross-linked with an anti-bacterial mAb, to target bacteria in the bloodstream in an acute infusion model in monkeys. In vitro studies demonstrated a variable level of complement-mediated binding (immune adherence) of Pseudomonas aeruginosa (strain PAO1) to primate E in serum. In vivo experiments in animals depleted of complement revealed that binding of bacteria to E was <1% before administration of the bispecific reagent, but within 5 min of its infusion, >99% of the bacteria bound to E. In complement-replete monkeys, a variable fraction of infused bacteria bound to E. This finding may have significant implications in the interpretation of animal models and in the understanding of bacteremias in humans. Treatment of these complement-replete monkeys with the bispecific reagent led to >99% binding of bacteria to E. Twenty-four-hour survival studies were conducted; several clinical parameters, including the degree of lung damage, cytokine levels, and liver enzymes in the circulation, indicate that the bispecific mAb reagent provides a degree of protection against the bacterial challenge.

Evaluation of fentanyl transdermal patches in rabbits: blood concentrations and physiologic response

In the study reported here, we sought to evaluate transdermal fentanyl patches for their ability to achieve detectable plasma concentrations with minimal adverse effects in New Zealand White rabbits. Fentanyl patches were applied to the dorsum after removing hair either by clipping or by application of a depilatory agent. Blood samples were collected every 12 h for a total of 96 h (24 h after patch removal) for determination of plasma fentanyl concentration. At those times, rabbits were assessed for changes in body temperature, heart rate, respiratory rate, and body weight. In rabbits with clipped hair, where rapid hair re-growth was not a mitigating factor, mean plasma fentanyl concentration reached a mean (+/- SEM) peak of 1.11 +/- 0.32 ng/ml at 24 h, decreased to 0.77 +/- 0.21 ng/ml at 72 h, and was negligible at 96 h. In rabbits with depilated hair, peak concentration was obtained at 12 h (6.7 +/- 0.57 ng/ml) and decreased gradually to 0.27 +/- 0.06 ng/ml at 72 h. In a second group of fentanyl-treated rabbits in which hair started growing back within 24 h, plasma fentanyl concentration was not detectable. Control and fentanyl-treated rabbits with clipped hair had no effect from the experimental manipulations other than slight loss in body weight. In the depilatory group, two rabbits appeared moderately sedated during the initial 12-h period, and had decreased respiratory rate for 24 h. In conclusion, rabbits tolerate the transdermal fentanyl patch well. Hair regrowth in rabbits may present a complicating factor that impedes dermal absorption of fentanyl. The application of a depilatory agent lead to early and rapid absorption of fentanyl causing undue sedation in some rabbits and lack of sustained plasma concentrations for the desired three-day period.

The effect of food restriction on the composition of intestinal microflora in rats

The effect of a food-restricted diet on the fecal microflora of rats was studied by determining total anaerobic bacteria, bacterial cellular fatty acids, and the predominant intestinal bacteria shown by polymerase chain reaction (PCR) primers specific for the 16S rRNA gene sequences of 12 bacterial species. Twenty-four female Fischer 344 rats, 57 days old were divided into two groups and maintained on an NIH-31 diet. One group was fed ad libitum while the other group received 60% of ad libitum food intake (40% food restriction supplemented with vitamins and minerals equal to the ad libitum animals). After 2, 10, and 20 weeks on this dietary regimen, groups of four animals were sacrificed and the intestinal contents analyzed for changes in the bacterial flora. The anaerobic population for two-week (short-term) food-restricted rats was 3.2 x 10(8) per gram, slightly less than the 9.1 x 10(8) per gram found in the ad libitum-fed rats. The anaerobic populations in 20-week food restricted and ad libitum fed rats were 1.9 x 10(9) and 2.7 x 10(9) per gram, respectively. The total anaerobic population did not change significantly in either group during the 20-week study. No statistically significant differences were observed in the bacterial cellular fatty acid profiles between the two groups as determined by gas-liquid chromatography. PCR analysis of the intestinal contents indicated no significant shifts in the predominant flora due to dietary changes. The results, using three different methods to detect changes in the rat intestinal microflora, suggest that long-term dietary restriction had little effect on the microflora of female Fischer 344 rats.

Reduction of malachite green to leucomalachite green by intestinal bacteria

Intestinal microfloras from human, rat, mouse, and monkey fecal samples and 14 pure cultures of anaerobic bacteria representative of those found in the human gastrointestinal tract metabolized the triphenylmethane dye malachite green to leucomalachite green. The reduction of malachite green to the leuco derivative suggests that intestinal microflora could play an important role in the metabolic activation of the triphenylmethane dye to a potential carcinogen.

Characterization of Y chromosomal deoxyribonucleic acid fragments and translocations by Southern blot analysis

Hybridization of Y chromosome-specific probes to Southern blots of genomic deoxyribonucleic acid from patients with chromosomal variants permits direct and rapid characterization of the chromosomal content. We have used two single-copy Y chromosomal sequences specific for the short arm (47z and DP34) and one repeated sequence specific to the long arm (Y3.4) to study several patients with different types of sex chromosomal abnormalities, including three patients with gonadal dysgenesis and the karyotype 45,X/46,X + fragment, two females with Y autosomal translocations involving similar regions of the Y chromosome (46,XX,t(Y;14)(q11,p11) and 46,XY,t(Y;15)(q11,p11), two males with very small Y chromosomes (del(Y)(q12) and i(Yp], and a 45,X male with a small Y autosomal translocation. These techniques are more sensitive than chromosome banding and thus are an important adjunct to karyotyping for analysis of chromosomal content. For patients with gonadal dysgenesis and uncharacterized fragments, demonstration of Y chromosomal sequences identifies an important risk factor for the development of gonadoblastoma. For other patients, accurate identification of Y chromosomal content may facilitate prediction of the patient's phenotype.

Skin variations in blacks

There are several skin variations normally found in blacks. These variations include Voigt's or Futcher's lines, midline hypopigmentation, pigmentation of the nails, oral pigmentation, plantar hyperpigmented macules, leukoedema of the oral mucosa, pearly penile papules, punctate pits and keratoses of the palms. It is important for health care providers in general and dermatologists in particular to recognize these variations in black skin. In the past, these skin variations have been viewed by physicians and sometimes patients as being abnormal and/or pathologic. Recognition of these benign variations in black skin will aid in correct identification and avoidance of sometimes unnecessary treatment.

Protease inhibitor profile of black Americans with and without chronic cardiopulmonary disease

An epidemiologic study of protease inhibitor (alpha(1)-antitrypsin) was undertaken among 599 ambulatory and hospitalized black American patients with chronic cardiopulmonary disease referred for pulmonary function testing, and 115 ethnically matched, healthy control subjects. Clinical evaluation consisted of respiratory questionnaire completion, physical examination, chest radiograph, and spirography. Protease inhibitor evaluation consisted of measurement of serum trypsin inhibitory capacity in all subjects corrected by comparison with control sera, while 200 of these subjects were phenotyped for alpha(1)-antitrypsin electrophoretic variants.Results showed mean serum trypsin inhibitory capacity for all subjects was 1.56, SD ± 0.47 mg/ml, while corrected values were 111.2, SD ± 30.5 percent of control. Acute phase reactivity was present for patients with heart disease, pulmonary malignancy, p<0.01 for both, and pulmonary fibrosis, p<0.05, when compared with controls. Prevalence of protease inhibitor variants in 29 controls was two heterozygotes for the Z variant (seven percent), and one homozygote for the S variant. Among 94 patients with chronic obstructive pulmonary disease, prevalence was 1.1 percent each for ZZ and SZ phenotypes, and 2.1 percent for MZ. Suprprisingly, the sole ZZ patient had asthmatic bronchitis rather than emphysema.Computed allele frequencies for Pi M and Z were comparable to those for a random sample of black Americans in St. Louis, but differed from a sample of black infants in Brooklyn, NY.These results indicate that protease inhibitor deficiency variants are not as uncommon among black Americans as the literature suggests. Furthermore, the heterozygous state is not necessarily a risk factor in development of chronic obstructive pulmonary disease. Protease inhibitor deficiency states therefore appear to play less important a role in etiology of chronic cardiopulmonary disease in black Americans than among their Caucasian counterparts.Preliminary work was published in abstract form.(1)

Readmission experiences of a cohort of discharges 1953-1957. Cohort followed for five years from date of discharge

The establishment of realistic read-mission rates has always been a problem for the Mental Hospital Administrator. A cohort of discharges from Brandon Hospital for Mental Diseases, discharged in the years 1953–57 inclusive, of 1,113 patients, was followed in the community for five years to establish time specific readmission rates. The results reported indicate the following:

1) Most of the patients lost to the study were lost during the first year of the follow-up.

2) The readmission rate for males during the full five-year period was slightly lower than for females. First admission discharges had lower read-mission rates than readmission discharges.

3) Schizophrenic patients exhibit the highest readmission rates.

4) Almost half the readmissions for the whole five-year period occurred during the first year following discharge.

5) In general, readmission rates declined the longer patients stayed out of hospital.