The Effect of Esophageal and Gastric Distension on the Crural Diaphragm

Background The mechanism of prevention of gastric reflux into the esophagus is not exactly known. The lower esophagus has a barrier function provided by the lower esophageal sphincter. We investigated the hypothesis that the crural diaphragm shares in the barrier function not only mechanically but also actively through a crural–esophageal–gastric reflex action. Methods The study was performed during repair of abdominal ventral and incisional hernias in 20 subjects (11 men, 9 women; age 38.6 ± 4.8 years). The electromyographic response of the crural diaphragm to individual balloon distension of esophagus and stomach was recorded by means of a needle electrode inserted into the crural diaphragm and connected to an electromyographic apparatus. The recordings were repeated after separate crural, esophageal, and gastric anesthetization. Results The crural diaphragm exhibited basal motor unit action potentials, which decreased on esophageal distension (P < 0.001) after a mean latency of 17.3 ± 2.8 SD ms. The crural diaphragm response to esophageal distension did not occur after the crural diaphragm or esophagus was anesthetized. Gastric distension effected an increase of crural diaphragm electromyographic activity with a mean latency of 18.4 ± 4.6 ms; this effect could not be achieved after the crural diaphragm or stomach was anesthetized. Conclusions The crural diaphragm has a resting tone that relaxes after esophageal distension and contracts after gastric distension. This sphincter-like action of the crural diaphragm appears to be a reflex and is mediated through the esophagocrural inhibitory and gastrocrural excitatory reflexes. The crural diaphragm seems to share actively in the gastroesophageal competence mechanism.     

Cytogenetic effects in children treated with methylphenidate

In recent years there has been a surge in methylphenidate (Ritalin) use for treatment of attention deficit/hyperactivity disorder (ADHD) in children. However, there is a paucity of information on whether this drug poses any potential health risks, such as mutagenicity or carcinogenicity, for humans. To address this issue, we investigated whether this central nervous system stimulant produces cytogenetic abnormalities in pediatric patients at therapeutic levels. In a population composed of twelve children treated with therapeutic doses of methylphenidate, we analyzed three cytogenetic endpoints in peripheral blood lymphocytes obtained before and three months after initiation of treatment with this drug. In all participants, treatment induced a significant 3, 4.3 and 2.4-fold increase in chromosome aberrations, sister chromatid exchanges and micronuclei frequencies, respectively (P=0.000 in all cases). These findings warrant further investigations of the possible health effects of methylphenidate in humans, especially in view of the well-documented relationship between elevated frequencies of chromosome aberrations and increased cancer risk.     

Synthesis and Antioxidant Activity of New Pyridines Containing Gallate Moieties

Pyridines containing the galloyl moiety have been prepared utilizing 4‐acetyl pyrogallol. In addition, fused pyridines were synthesized from the obtained pyridines via further chemical transformations. The results indicated that compound 4a showed stronger DPPH scavenging activity than the other compounds, and the scavenging effect decreased in the following order 4a > t‐BHQ > 2a > 2b > 3a > 3b > 4b . Accordingly, other antioxidant assays were conducted for 4a . The results suggested that compound 4a could be a good antioxidant candidate. The absence of mortality of rats receiving 5000 mg/kg body weight of 4a as single oral dose may indicate that it could be a safe antioxidant and may be used for further studies.

     

Radial nerve repetitive stimulation in myasthenia gravis

The purpose of this study was to compare the diagnostic yield of repetitive radial nerve stimulation (RNS) while recording from extensor indicis proprius (EIP) to other commonly used muscle-nerve combinations in patients with myasthenia gravis (MG). Radial RNS with recording from EIP was performed in 20 controls and 20 patients with MG. It revealed an abnormal decrement at rest in 35% of patients compared to 11% with ulnar nerve stimulation, 64% with spinal accessory nerve stimulation, and 74% with facial nerve stimulation. Radial-EIP RNS is a reliable technique in the evaluation of MG and appears more sensitive than ulnar nerve RNS.     

Comparison between pernasal flocked swabs and nasopharyngeal aspirates for detection of common respiratory viruses in samples from children

In this prospective study we compared the use of pernasal flocked swab samples with the use of nasopharyngeal aspirate (NPA) samples for the detection of respiratory viruses from 455 children less than 5 years of age. Overall, the sensitivity and the specificity of the pernasal flocked swab samples were 98.5% and 100%, respectively. The excellent sensitivity of the flocked swab samples in combination with the rapid means by which they may be collected makes them an alternative to NPA samples, whose collection is more invasive.     

Therapeutics in pediatric epilepsy,Part 1: The new antiepileptic drugs and the ketogenic diet

Epilepsy is one of the most common and challenging neurologic disorders affecting children. Although various modalities exist to treat pediatric-onset seizures, seizures in 25% of children who are diagnosed as having epilepsy remain refractory to available therapies. Of the 8 new antiepileptic drugs (AEDs) (felbamate, gabapentin, lamotrigine, topiramate, tiagabine, levetiracetam, oxcarbazepine, and zonisamide), all but 2 (zonisamide and levetiracetam) have received Food and Drug Administration approval for adjunctive use in the pediatric population. However, most of the new AEDs used in adults have also been used in children, beyond the AEDs' approved indications. The ultimate goal of patient management is to choose the therapeutic option that provides the best chance of improving the patient's quality of life. Issues that relate to treatment choice include the likelihood of seizure recurrence, type and severity of seizures, available AED efficacies and toxicities, need for hematologic monitoring, ease of dosing, underlying medical conditions, medication interactions, urgency of initiating therapy, and cost. In this review, we discuss these issues for each of the 8 new AEDs; we also discuss the ketogenic diet and briefly review the older AEDs. Knowledge of the available AEDs will enable the practitioner to choose the best drug or drugs for individual patients.     

Heme oxygenase-1 expression protects melanocytes from stress-induced cell death: implications for vitiligo

To study protection of melanocytes from stress-induced cell death by heme oxygenases during depigmentation and repigmentation in vitiligo, expression of isoforms 1 and 2 was studied in cultured control and patient melanocytes and normal skin explants exposed to UV or bleaching agent 4-TBP. Similarly, expression of heme oxygenases was followed in skin from vitiligo patients before and after PUVA treatment. Single and double immunostainings were used in combination with light and confocal microscopic analysis and Western blotting. Melanocyte expression of heme oxygenase 1 is upregulated, whereas heme oxygenase 2 is reduced in response to UV and 4-TBP. Upregulation of inducible heme oxygenase 1 was also observed in UV-treated explant cultures, in skin of successfully PUVA-treated patients and in melanocytes cultured from vitiligo non-lesional skin. Heme oxygenase encoding genes were subsequently cloned to study consequences of either gene product on cell viability, demonstrating that HO-1 but not HO-2 overexpression offers protection from stress-induced cell death in MTT assays. HO-1 expression by melanocytes may contribute to beneficial effects of UV treatment for vitiligo patients.     

Impact of negative pressure wound drainage compared with natural wound drainage after thyroid tumour surgery: A meta-analysis

We conducted a meta-analysis to compare the effectiveness of negative pressure wound drainage to that of spontaneous wound drainage after thyroid tumour surgery. A thorough analysis of the literature up to July 2022 revealed that, of the 1234 patients who used surgery for thyroid tumours, 615 used negative pressure wound drainage and 619 used natural wound drainage. To measure the influence of negative pressure wound drainage in comparison to natural wound drainage following thyroid tumour surgery, mean difference (MD) and odds ratio (OR) with 95% confidence intervals (CIs) were measured using the contentious and dichotomous approaches with a random or fixed-effect model. Subjects who used negative pressure wound drainage had significantly higher averages for drained material (OR, 12.52; 95% CI, 6.78-18.26, P = 0.001), shorter drain placement times (MD, −1.06; 95% CI, 1.57 to −0.55, P = .001), lower rates of infection at the surgical site (OR, 0.17; 95% CI, 0.05-0.60, P = .006), higher rates of wound healing (OR, 5.91; 95% CI, 1.56-22.34, P = .009), and lower rate of wound seroma (OR, 0.21; 95% CI, 0.10-0.42, P < .001) in subjects after thyroid tumour surgery in comparison to subjects who used natural wound drainage after thyroid tumour surgery. Those who used negative pressure wound drainage had significantly higher averages of drained material, shorter drain placement times, lower rates of wound infection at the surgical site, higher rates of wound healing, and lower rates of wound seroma. Care must be used when analysing the results because of the small sample size of 7 of the 13 studies included in the meta-analysis and the lack of studies in several comparisons.