Midbrain organoids for Parkinson's disease (PD) - A powerful tool to understand the disease pathogenesis

Brain Organiods (BOs) are a promising technique for researching disease progression in the human brain. These organoids, which are produced from human induced pluripotent stem cells (HiPSCs), can construct themselves into structured frameworks. In the context of Parkinson's disease (PD), recent advancements have been made in the development of Midbrain organoids (MBOs) models that consider key pathophysiological mechanisms such as alpha-synuclein (α-Syn), Lewy bodies, dopamine loss, and microglia activation. However, there are limitations to the current use of BOs in disease modelling and drug discovery, such as the lack of vascularization, long-term differentiation, and absence of glial cells. To address these limitations, researchers have proposed the use of spinning bioreactors to improve oxygen and nutrient perfusion. Modelling PD utilising modern experimental in vitro models is a valuable tool for studying disease mechanisms and elucidating previously unknown features of PD. In this paper, we exclusively review the unique methods available for cultivating MBOs using a pumping system that mimics the circulatory system. This mechanism may aid in delivering the required amount of oxygen and nutrients to all areas of the organoids, preventing cell death, and allowing for long-term culture and using co-culturing techniques for developing glial cell in BOs. Furthermore, we emphasise some of the significant discoveries about the BOs and the potential challenges of using BOs will be discussed.

A simple technical innovation to prevent needle stick injuries among dental professionals

OBJECTIVE

Dental healthcare personnel face the potential danger of being exposed to infectious patients while administering local anesthesia injections during dental operations. This could lead to unintentional transfer of infectious diseases from patients to physicians. Although safety measures such as the One-hand-scoop technique and the use of safety syringes, plastic needle cap holders, and needles with safety caps are in place, there have been instances of needle stick injuries reported in clinics. This might be due to the lack of adherence to conventional safety measures or the impracticality of safety techniques and safety syringes. This article aims to demonstrate the utilization of dental tweezers, specifically London College tweezers or dental forceps, for the secure recapping of needles, eliminating the requirement for extra equipment or devices.

SUBJECTS AND METHODS

After obtaining ethical approval (Approval No.: 024-01-2024) from the College of Dentistry, Dar Al Uloom University, 67 dental professionals, with consent for participation in the study, were included. They were requested to use dental tweezers/London College tweezers and dental extraction forceps such as maxillary anterior, mandibular anterior, and maxillary bayonet root forceps individually to recap the local anesthetic needles. The efficacy of these techniques was evaluated against the one-hand scoop technique for its ease, convenience, and reliability in preventing needle stick injuries.

RESULTS

The evaluation of dental professionals regarding the ease of using dental tweezers to recap needles, compared to the one-hand scoop technique (p=0.592), maxillary bayonet root forceps (p=0.746), mandibular anterior forceps (p=0.380), and maxillary anterior forceps (p=0.808), did not yield statistically significant results. The assessment of the procedural simplicity of the one-hand scoop technique showed a satisfaction rate of over 40%, whereas the application of dental tweezers resulted in a satisfaction rate of 30%. However, the use of dental tweezers for needle recapping resulted in a satisfaction rate of over 50%, compared to a satisfaction rate of 30% for the one-handed scoop technique.

CONCLUSIONS

There is no statistically significant difference in the assessment of the efficacy of dental tweezers and the one-hand scoop technique, bayonet root forceps, mandibular anterior forceps, maxillary anterior forceps, and dental tweezers for the needle capping technique. Therefore, dental forceps can be used instead of the one-handed scoop approach. The needle recapping procedure outlined in our study, aimed at preventing needle stick injuries, is simple to implement, and all dental specialties have convenient access to the required instruments.

Perspectives and challenges in lip rejuvenation: a systematic review

OBJECTIVE

There is an abundance of information on facelifts, blepharoplasties, rhinoplasty, and other cosmetic surgical procedures for the upper third of the face, but little is known about perioral lip rejuvenation. The aim of this article is to examine the existing literature on lip rejuvenation and perioral procedures related to lip rejuvenation. Additionally, this article aims to highlight the importance of addressing perioral areas alongside lip rejuvenation procedures, rather than solely focusing on lip rejuvenation. We also discussed the extensive procedures and materials used for lip rejuvenation, such as hyaluronic acid, botulinum toxin A, abobotulinum, onabotulinum, incobotulinum, prabobotulinum, fat grafts, silicone fillers, human collagen, collagen stimulating procedures such as derma pens and derma rolls, radiation frequency, stem cells, and plasma therapy, as well as the underlying factors that contribute to varying success rates.

MATERIALS AND METHODS

A thorough literature search was done using PubMed, Cochrane, Ebsco search, Google Scholar, Scopus, and Web of Science for the articles pertaining to facial and lip cosmetic surgeries 1995-2020. Keywords for the search included anatomy of the face, facial aging, perioral areas, lip rejuvenation, botox, grafts, facelift, plastic surgery, stem cell therapy, plasma treatment, and cosmetic surgery.

RESULTS

37 articles met the study criteria. 14 out of 37 studies included procedures for lip and perioral region rejuvenation. The remaining 23 studies either involved lip procedures alone or lip procedures in conjunction with facial cosmetic procedures. Lip rejuvenation with perioral enhancement with hyaluronic acid gel demonstrated a 94.3% improvement on the lip fullness scale (LFS) one month after re-treatment. The amalgamation of lip and perioral region rejuvenation produces a synergistic effect. Whereas, sole lip rejuvenation procedures showed short-term results with less patient satisfaction, calling for secondary lip rejuvenation procedures. It was also observed that hyaluronic acid was the most commonly used agent for lip rejuvenation procedures with minimal or no side effects.

CONCLUSIONS

In conjunction with perioral rejuvenation, lip rejuvenation procedures produce more aesthetically appealing results. However, any cosmetic surgical or non-surgical procedure is limited by the nature and composition of the products used. The use of FDA-approved products for rejuvenation is strongly advised to avoid undesirable side effects. Further extensive research is required on the long-term outcomes and adverse effects of stem cell transplants, such as tumor development.

Microalgae biomass from swine wastewater and its conversion to bioenergy

Ever-increasing swine wastewater (SW) has become a serious environmental concern. High levels of nutrients and toxic contaminants in SW significantly impact on the ecosystem and public health. On the other hand, swine wastewater is considered as valuable water and nutrient source for microalgae cultivation. The potential for converting the nutrients from SW into valuable biomass and then generating bioenergy from it has drawn increasing attention. For this reason, this review comprehensively discussed the biomass production, SW treatment efficiencies, and bioenergy generation potentials through cultivating microalgae in SW. Microalgae species grow well in SW with large amounts of biomass being produced, despite the impact of various parameters (e.g., nutrients and toxicants levels, cultivation conditions, and bacteria in SW). Pollutants in SW can effectively be removed by harvesting microalgae from SW, and the harvested microalgae biomass elicits high potential for conversion to valuable bioenergy.

High prevalence of undiagnosed diabetes among tuberculosis patients in peripheral health facilities in Kerala

SETTING

Two tertiary care hospitals and 12 peripheral health institutions (PHIs) in Trivandrum, Kerala, India.

OBJECTIVE

To determine factors associated with the prevalence of diabetes mellitus (DM) among tuberculosis (TB) patients and examine differences in the proportion of new DM cases among TB patients diagnosed at tertiary care centres and PHIs.

DESIGN

A descriptive study: TB patients diagnosed during March-September 2012 were screened for known DM. Those with unknown DM status were tested for random blood glucose and fasting blood glucose (FBG); FBG ≥ 126 mg/dl was diagnosed as new DM.

RESULTS

Of 920 TB patients, 689 (72%) were male and the mean (standard deviation) age was 47.6 (16.4) years. Of these, 298 (32.4%) were diabetic: 235 (26%) had previously known DM and 63 (7%) were newly diagnosed. During the screening at PHIs and tertiary care hospitals, respectively 30/183 (16.4%) and 33/737 (4.5%) were newly diagnosed with DM (OR 3.71; 95%CI 2.17-6.32). Overall, age >50 years and pulmonary tuberculosis were independently associated with a higher prevalence of diabetes.

CONCLUSION

As nearly one in three TB patients had DM, we recommend that TB patients should be routinely screened for DM in Kerala. As the proportion of new DM was higher among TB patients diagnosed at PHIs, we would recommend that specific attention and investment be directed to PHIs.

Crystal structure of ATP-binding subunit of an ABC transporter from Geobacillus kaustophilus

The ATP binding cassette (ABC) transporters, represent one of the largest superfamilies of primary transporters, which are very essential for various biological functions. The crystal structure of ATP-binding subunit of an ABC transporter from Geobacillus kaustophilus has been determined at 1.77 Å resolution. The crystal structure revealed that the protomer has two thick arms, (arm I and II), which resemble 'L' shape. The ATP-binding pocket is located close to the end of arm I. ATP molecule is docked into the active site of the protein. The dimeric crystal structure of ATP-binding subunit of ABC transporter from G. kaustophilus has been compared with the previously reported crystal structure of ATP-binding subunit of ABC transporter from Salmonella typhimurium.

Crystal structures of type IIIH NAD-dependent D-3-phosphoglycerate dehydrogenase from two thermophiles

In the L-Serine biosynthesis, D-3-phosphoglycerate dehydrogenase (PGDH) catalyzes the inter-conversion of D-3-phosphoglycerate to phosphohydroxypyruvate. PGDH belongs to 2-hydroxyacid dehydrogenases family. We have determined the crystal structures of PGDH from Sulfolobus tokodaii (StPGDH) and Pyrococcus horikoshii (PhPGDH) using X-ray diffraction to resolution of 1.77Å and 1.95Å, respectively. The PGDH protomer from both species exhibits identical structures, consisting of substrate binding domain and nucleotide binding domain. The residues and water molecules interacting with the NAD are identified. The catalytic triad residues Glu-His-Arg are highly conserved. The residues involved in the dimer interface and the structural features responsible for thermostability are evaluated. Overall, structures of PGDHs with two domains and histidine at the active site are categorized as type IIIH and such PGDHs structures having this type are reported for the first time.

Human skin neural crest progenitor cells are susceptible to BRAF(V600E)-induced transformation

Adult stem cells are multipotent and persist in small numbers in adult tissues throughout the lifespan of an organism. Unlike differentiated cells, adult stem cells are intrinsically resistant to senescence. It is unclear how adult stem cells in solid organs respond to oncogenic stimulation and whether these cells have a role in tumor initiation. We report here that expression of BRAF(V600E) in human neural crest progenitor cells (hNCPCs) did not induce growth arrest as seen in human melanocytes, but instead, increased their cell proliferation capacity. These cells (hNCPCs(V600E)) acquired anchorage-independent growth ability and were weakly tumorigenic in vivo. Unlike in human melanocytes, BRAF(V600E) expression in hNCPCs did not induce p16(INK4a) expression. BRAF(V600E) induced elevated expression of CDK2, CDK4, MITF and EST1/2 protein in hNCPCs, and also induced melanocytic differentiation of these cells. Furthermore, overexpression of MITF in hNCPCs(V600E) dramatically increased their tumorigenicity and resulted in fully transformed tumor cells. These findings indicate that hNCPCs are susceptible to BRAF(V600E)-induced transformation, and MITF potentiates the oncogenic effect of BRAF(V600E) in these progenitor cells. These results suggest that the hNCPCs are potential targets for BRAF(V600E)-induced melanocytic tumor formation.

Carotid Stump Syndrome: Outcome from Surgical Management

OBJECTIVES

in patients with occluded internal carotid arteries the carotid stump is a potential source of microemboli resulting in the persistence of retinal or cerebral ischaemic symptoms. We report 25 patients who had persistent cerebral and retinal ischaemic symptoms with an occluded ipsilateral ICA and a carotid stump who underwent surgical exclusion of the stump.

METHODS

between January 1988 and January 1998, 332 patients underwent carotid endarterectomy. Twenty-five patients (20 males: five females; mean age 58.9 (range 44-78 years)) had carotid stump exclusion. Indications for surgery were transient ischaemic attack (22), amaurosis fugax (eight) and cerebrovascular accident (13). Three patients had undergone contralateral carotid endarterectomy and 12 had significant contralateral stenosis. Twenty patients were being treated with aspirin and four with warfarin at the time of presentation.

RESULTS

the diagnosis of carotid stump was made in 22 patients by angiography. In the remaining three patients duplex alone was diagnostic in two patients. In the third case duplex was combined with magnetic resonance angiography (MRA) to confirm the diagnosis. Stump exclusion was carried out by oversewing the ICA origin. All but one patient remained symptom free at follow-up.

CONCLUSION

carotid stump syndrome should be considered as a likely clinical entity in patients with an occluded ICA and persisting cerebral and retinal microembolic symptoms. Surgical exclusion of the carotid stump is a safe and effective method of treatment.

Nerve injury induces a rapid efflux of nitric oxide (NO) detected with a novel NO microsensor

An early step in repair of the leech CNS is the appearance of endothelial nitric oxide synthase (eNOS) immunoreactivity and NOS activity, but coincident generation of NO at the lesion after injury has not been shown. This is important because NO can regulate microglial cell motility and axon growth. Indirect measurement of NO with the standard citrulline assay demonstrated that NO was generated within 30 min after nerve cord injury. A polarographic NO-selective self-referencing microelectrode that measures NO flux noninvasively was developed to obtain higher spatial and temporal resolution. With this probe, it was possible to demonstrate that immediately after the leech CNS was injured, NO left the lesion with a mean peak efflux of 803 +/- 99 fmol NO cm(-2) sec(-1). NO efflux exponentially declined to a constant value, as described through the equation f(t) = y(o) + ae(-t/tau), with tau = 117 +/- 30 sec. The constant y(o) = 15.8 +/- 4.5 fmol cm(-2) represents a sustained efflux of NO. Approximately 200 pmol NO cm(-2) is produced at the lesion (n = 8). Thus, injury activates eNOS already present in the CNS and precedes the accumulation of microglia at the lesion, consistent with the hypothesis that NO acts to stop the migrating microglia at the lesion site.

Nitric oxide influences injury-induced microglial migration and accumulation in the leech CNS

Damage to the leech or mammalian CNS increases nitric oxide (NO) production and causes accumulation of phagocytic microglial cells at the injury site. The aim of this study was to determine whether NO plays a role in microglial migration and accumulation at lesions in which NO is generated by a rapidly appearing endothelial nitric oxide synthase (eNOS) in leeches. Immunohistochemistry and cytochemistry demonstrated active eNOS before and throughout the period of microglial accumulation at the lesion. Decreasing NO synthesis by application of the NOS inhibitor N(w)-nitro-L-arginine methyl ester (1 mM) significantly reduced microglial accumulation, whereas its inactive enantiomer N(w)-nitro-D-arginine methyl ester (1 mM) resulted in microglial accumulation similar to that in crushed controls. Increasing NO with the donor spermine NONOate (SPNO) (1 mM) also inhibited accumulation, but not in the presence of the NO scavenger 2-(4-carboxyphenyl)-4,4,5, 5-teramethylimidazoline-oxyl-3-oxide (50 microM). The effect of SPNO was reversed by washout. SPNO application reduced average microglial migratory speeds and even reversibly arrested cell movement, as measured in living nerve cords. These results suggest that NO produced at a lesion may be a stop signal for microglia to accumulate there and that it can act on microglia early in their migration. Thus, NO may assume a larger role in nerve repair and recovery from injury by modulating accumulation of microglia, which appear to be important for axonal regeneration.

Injury-induced expression of endothelial nitric oxide synthase by glial and microglial cells in the leech central nervous system within minutes after injury

It is known that nitric oxide (NO) is produced by injured tissues of the mammalian central nervous system (CNS) within days of injury. The aim of the present experiments was to determine the cellular synthesis of NO in the CNS immediately after injury, using the CNS of the leech which is capable of synapse regeneration, as a step towards understanding the role of NO in nerve repair. We report that within minutes after crushing the nerve cord of the leech, the region of damage stained histochemically for NADPH diaphorase, which is indicative of nitric oxide synthase (NOS) activity, and was immunoreactive for endothelial NOS (eNOS). On immunoblots of leech CNS extract, the same antibody detected a band with a relative molecular mass of 140,000, which is approximately the size of vertebrate eNOS. Cells expressing eNOS immunoreactivity as a result of injury were identified after freezing nerve cords, a procedure that produced less tissue distortion than mechanical crushing. Immunoreactive cells included connective glia and some microglia. Calmodulin was necessary for the eNOS immunoreactivity: it was blocked by calmodulin antagonist W7 (25 microM), but not by similar concentrations of the less potent calmodulin antagonist W12. Thus in the leech CNS, in which axon and synapse regeneration is successful, an increase in NOS activity at lesions appears to be among the earliest responses to injury and may be important for repair of axons.

Practical management aspects of intraoperative arrhythmias: the anesthesiologist's viewpoint

A wide range of cardiac arrhythmias may be observed during anesthesia and intraoperatively and they usually have a multifactorial origin. A broad understanding of the various arrhythmogenic factors is important in the safe and effective treatment of these rhythm disorders. A large number of intraoperative arrhythmias can be successfully managed by expectant observation and elimination of the frequently implicated stimuli, e.g., hypercapnia, anesthetic overdose, hypoxia, excessive sympathetic activity, or surgical stimulation. Certain arrhythmias, however, depending on their intrinsic prognosis and the hemodynamic state of the patient, require immediate treatment with antiarrhythmic drugs or direct current countershock, or both.

Plasma free norepinephrine and epinephrine concentrations following diazepam-ketamine induction in patients undergoing cardiac surgery

Ketamine causes cardiovascular stimulation, presumably, by increasing central sympathetic activity. This study was undertaken to find out if diazepam in appropriate doses could abolish or moderate the central sympathetic and cardiovascular stimulation following ketamine in patients undergoing cardiac surgery. Twelve patients, scheduled for valvular replacement (8) and direct aortocoronary bypass graft operations (4) were studied. After premedication with diazepam 0.15 mg/kg orally and morphine sulphate 0.15 mg/kg i.m., they were induced with diazepam 0.3 mg/kg i.v., followed 10 min later by ketamine 2 mg/kg i.v. Direct arterial pressure by a strain gauge from the radial artery and heart rate by EKG were continuously recorded. Plasma free norepinephrine, measured by Vendsalu's method, in the arterial blood was 0.39 +/- 0.03 ng/ml prior to induction, 0.39 +/- 0.03 ng/ml 10 min after diazepam and 0.42 +/- 0.05 ng/ml (P greater than 0.05) 5 min after ketamine administration. Plasma free epinephrine concentrations were 0.10 +/- 0.04 ng/ml prior to induction, 0.06 +/- 0.03 ng/ml (P less than 0.05) 10 min after diazepam and 0.01 +/- 0.003 ng/ml (P less than 0.05) 5 min after ketamine. Heart rate and systolic pressure did not change significantly throughout the study period. Diastolic pressures were elevated significantly (P less than 0.05) 5 min after ketamine administration, amounting to a 12% increase over baseline. Diazepam-ketamine induction in cardiac surgical patients did not result in clinically significant central sympathetic or cardiovascular stimulation.