Initial evaluation of systemic and regional pCO2 gradients as markers of mesenteric hypoperfusion

BACKGROUND: Mesenteric ischemia is a life-threatening emergency with a mortality rates still ranging between 60% and 100%. AIM: To evaluate the systemic and regional pCO2 gradients changes induced by mesenteric ischemia-reperfusion injury. In addition, we sought to determine if other systemic marker of splanchnic hypoperfusion could detect the initial changes in intestinal mucosal microcirculation after superior mesenteric artery occlusion. METHODS: Seven pentobarbital anesthetized mongrel dogs (20.6 +/- 1.1 kg) were subjected to superior mesenteric artery occlusion for 45 minutes, and followed for an additional 120 minutes. Systemic hemodynamic was evaluated through a Swan-Ganz and arterial catheters, while gastrointestinal tract perfusion by superior mesenteric vein and jejunal serosal blood flows (ultrasonic flowprobe). Intestinal oxygen delivery, extraction and consumption (DO2intest, ERO2intest and VO2intest, respectively), intramucosal pH (gas tonometry), and mesenteric-arterial and mucosal arterial pCO2 gradients (D(vm-a)pCO2 and D(t-a)pCO2, respectively) were calculated. RESULTS: Superior mesenteric artery occlusion was not associated with significant changes on systemic hemodynamics parameters. A significant increase of D(vm-a)pCO2 (1.7 +/- 0.5 to 5.7 +/- 1.8 mm Hg) and D(t-a)pCO2 (8.2 +/- 4.8 to 48.7 +/- 4.6 mm Hg) were detected. During the reperfusion period a significant decrease on DO2intest (67.7 +/- 9.9 to 38.8 +/- 5.3 mL/min) and a compensatory increase on ERO2intest from 5.0 +/- 1.1% to 12.4 +/- 2.7% was observed. CONCLUSION: We conclude that gas tonometry can detect the mesenteric blood flow disturbances sooner than other analyzed parameters. Additionally, we demonstrated that changes on systemic or regional pCO2 gradients are not able to detect the magnitude of intestinal mucosal blood flow reduction after mesenteric ischemia-reperfusion injury.     

Physiopathology and current treatments of androgenetic alopecia: Going beyond androgens and anti‐androgens

Androgenetic alopecia (AGA) is the most diagnosed hair loss dysfunction. Its physiopathology comprises a genetic predisposition affording an exacerbated response of the hair follicles cells to androgens aggravated by scalp inflammation and extrinsic factors. This paper presents a review of the mechanisms and extrinsic factors involved in the AGA physiopathology as well as its conventional and emerging treatments. The research focused on reports regarding AGA physiopathology and treatments published between January 2001 and July 2019 in medical and related journals. The most used medical treatments for AGA—minoxidil and finasteride—present non satisfactory results in some cases. Currently, the low‐level laser therapy is recognized as a safe and effective treatment for AGA. Some minimally invasive techniques—mesotherapy, microneedling, carboxytherapy, and platelet‐rich plasma—are also used to stimulate hair growth. Pharmaceutical substances with mechanisms differing from the anti‐androgen activity are under current investigation and many of them have botanical origins; however, formulations with higher performance are required, and the hair follicles ability of being a drug and nanoparticle reservoir has been researched. The association of different strategies, that is, substances with synergic mechanisms and the use of advantageous technologies associated with lifestyle changes could improve the treatment outcomes.     

Repair of furcal perforation treated with mineral trioxide aggregate in a primary molar tooth: 20-month follow-up

Furcal perforations may occur during access opening of the pulp chamber or cavity preparation. The perforation can cause an inflammatory reaction in the periodontal ligament. Management of these iatrogenic accidents can pose a significant clinical challenge, mainly when they occur in primary teeth. Current developments in the techniques and materials utilized for root perforation repair have enhanced this procedure's prognosis. Recently, mineral trioxide aggregate (MTA) has been used for several dental purposes. This biocompatible material promotes bone healing and elimination of clinical symptoms. The purpose of this case report was to describe the treatment of a furcal perforation using mineral trioxide aggregate (MTA) in a primary molar tooth. After 20 months, the tooth was asymptomatic. The radiolucent image had disappeared and bone formation at the furcation area had been observed, suggesting healing of the underlying periodontal tissues. Therefore, MTA may be considered an alternative option for the repair of furcal perforation in primary teeth, prolonging the longevity of these dental elements.     

The effect of early versus delayed challenge after vaccination in controlling SHIV 89.6P infection

We sought to determine how effectively a CD8+ T cell inducing vaccine controls SHIV-89.6P infection in rhesus macaques at a range of challenge times post-vaccination. To this end, twenty eight Mamu-A*01+ rhesus macaques were given replication incompetent human serotype 5 adenovirus vector expressing SIVmac239 gag DNA and boosted 24 weeks later. Groups of 4 monkeys were then challenged with SHIV-89.6P at 1, 3, 6, 12, and 24 weeks after the boost. We compared the kinetics of viral load, CD4+ and virus-specific CD8+ T cells in these macaques. Measurements of CD8+ T cells taken before challenge show an exponential decay between 1 and 12 weeks following vaccination (p<0.0001). After week 12, no further decay was observed. Twenty of 24 vaccinated animals maintained more CD4+ T cells and kept their viral load at least one order of magnitude lower than the control animals throughout the chronic phase of the study. All 24 vaccinated animals survived the duration of the study. The viral and T cell kinetics over the first two weeks differed between the vaccinated groups, with more recent vaccination improving the early control of virus (p-value=0.027). The rates of virus specific CD8+ T cell expansion were greater in animals having higher viral loads at one week (r=0.45, p=0.029), suggesting that the kinetics of early viral load may have a role in virus specific CD8+ T cell generation, although these early differences did not lead to different clinical outcomes within the vaccinated animals.     

A novel cell line that retains the morphological characteristics of the cells and matrix of odontogenic myxoma

Little is known about the histogenesis of the human odontogenic myxoma or the relation between tumour cells and the matrix. In order to attempt to remedy this situation, we established and investigated a cell line derived from a human odontogenic myxoma. To our knowledge this is the first cell line derived from this tumour. The cell line, named Mix 1, preserved features of the tumour cells. Mix 1 cells expressed vimentin, type I collagen, fibronectin, tenascin and hyaluronic acid. Ultrastructural analysis of cells of the tumour and cell line demonstrated similarities, both containing Golgi apparatus, rough endoplasmic reticulum and mitochondria indicative of secretory cells. Ultrastructural analysis showed the matrix to be represented by bundles of collagen fibrils in the tumour, and by irregular filaments in cultures more than 60 days old. The Mix 1 cell line promises to be an excellent model for investigating the biology of the odontogenic myxoma.     

THE ROLE OF HUMORAL ANTIBODIES IN REJECTION OF SKIN HOMOGRAFTS IN RABBITS : I. PASSIVE TRANSFER OF ISOIMMUNE SERUM TO CONDITIONED HOSTS

Gross and microscopic observations of skin homograft rejection carried out in cortisone-conditioned and non-conditioned rabbits seem to indicate that humoral antibodies play an important role in the phenomenon. Thus, local administration of isoimmune serum to animals bearing skin homografts resulted in a significantly earlier rejection of that particular test graft without modifying the course of a neighboring control-skin graft. This result appears to support the idea that homograft rejection is not only due to cellular antibodies but to a combination of both humoral and cellular immune responses, which should not be regarded as completely unrelated.     

EFFECT OF DIFFERENT PROPHYLAXIS METHODS ON SOUND AND DEMINERALIZED ENAMEL

Considering the importance of professional plaque control for caries prevention, this study comprised an in vitro evaluation of wear by two prophylaxis methods (sodium bicarbonate jet – Profident and pumice and brush) on sound bovine enamel and with artificial carious lesions. Sixty enamel fragments were employed (4x4mm), which were divided into 4 groups: GI – 15 sound blocks treated with pumice and brush; GII – 15 sound blocks treated with Profident; GIII – 15 demineralized blocks treated with pumice and brush, and GIV – 15 demineralized blocks treated with Profident. In the fragments of Groups III and IV, artificial carious lesions were simulated by immersion in 0.05M acetic acid solution 50% saturated with bovine enamel powder at 37^oC for 16h. The specimens were submitted to the prophylactic treatments for 10 seconds. Wear analysis was performed by profilometer and revealed the following results: 0.91μm – GI; 0.42μm – GII; 1.6μm – GIII, and 0.94μm – GIV. The two-way ANOVA and Tukey''s test (p<0.05) revealed significant difference between all groups. Scanning electron microscopy images were employed to illustrate the wear pattern, with observation of larger alteration on the demineralized enamel surface (GIII; GIV), round-shaped wear on GI and GIII and blasted aspect on GII and GIV. The study indicated that the demineralized enamel presented more wear than the sound enamel, and the brush led to larger wear when compared to Profident.