Obesity as a Risk Factor for Severe COVID-19 in Hospitalized Patients: Epidemiology and Potential Mechanisms

SARS-CoV-2 infection is a global public health problem, causing significant morbidity and mortality. Evidence shows that obesity is a recognized risk factor for hospitalization, admission to critical care units, and the development of serious complications from COVID-19. This review analyzes the available epidemiological evidence that relates obesity to a higher risk of severity and mortality from COVID-19, examining the possible pathophysiological mechanisms that explain this phenomenon on a cellular and molecular level.

High accuracy astigmatic-focusing system for laser targets

An accurate location of the focal position with respect to a solid target is a key task for different applications, for instance, in laser driven plasma acceleration for x-ray generation where minimum required intensities are above 10¹⁴W/cm². For such practical applications, new approaches for focus location and target delivery techniques are needed to achieve the required intensity, repeatability, and stability. There are different techniques to accomplish the focusing and target positioning task such as interferometry-, microscopy-, astigmatism-, and nonlinear-optics-based techniques, with their respective advantages and limitations. We present improvements of a focusing technique based on an astigmatic method with potential applications where maximum intensity at the target position is necessary. The presented technique demonstrates high accuracy up to 5 µm, below the Rayleigh range, and also its capability to work in rough surfaces targets and tilt tolerance of the target, with respect to the normal of the target surface.

Phosphatase-1 and -2A inhibition modulates apoptosis in human osteoarthritis chondrocytes independently of nitric oxide production

OBJECTIVE

To characterise the role of phosphatase-1 and -2A (PP1/2A) in the modulation of apoptosis in human osteoarthritis (OA) chondrocytes.

METHODS

Human OA chondrocytes were isolated from cartilage obtained from the femoral heads of patients undergoing joint replacement surgery. Cell viability was evaluated by MTT assay. Apoptosis was quantified by ELISA, which measures DNA fragmentation. Nitric oxide (NO) production was evaluated by the Greiss method, and inducible nitric oxide synthase (iNOS) protein synthesis was studied by western blotting.

RESULTS

Inhibition of PP1/2A by the specific inhibitor okadaic acid (OKA) dose and time dependently caused a reduction of cell viability (OKA at 50 nmol/l: a reduction to 60% and 43% at 48 and 72 hours, respectively). Genomic DNA from chondrocytes treated with OKA at 50 and 100 nmol/l for 48 hours displayed increased internucleosomal DNA fragmentation by 11 and 13 fields, respectively. Light microscopy and DAPI studies showed that OKA induced DNA condensation and fragmentation, typical of death by apoptosis. The caspase inhibitors Z-VAD-FMK and Z-DEVD-FMK increased cell viability, reduced by OKA at 50 nmol/l to 87% and 73%, respectively. OKA did not increase iNOS protein synthesis or NO production.

CONCLUSION

PP1/2A modulate apoptosis in human OA chondrocytes; this is independent of NO production but dependent on caspases.

Treatment of winery wastewater by an anaerobic sequencing batch reactor

Treatment of winery wastewater was investigated using an anaerobic sequencing batch reactor (ASBR). Biogas production rate was monitored and permitted the automation of the bioreactor by a simple control system. The reactor was operated at an organic loading rate (ORL) around 8.6 gCOD/L.d with soluble chemical oxygen demand (COD) removal efficiency greater than 98%, hydraulic retention time (HRT) of 2.2 d and a specific organic loading rate (SOLR) of 0.96 gCOD/gVSS.d. The kinetics of COD and VFA removal were investigated for winery wastewater and for simple compounds such as ethanol, which is a major component of winery effluent, and acetate, which is the main volatile fatty acid (VFA) produced. The comparison of the profiles obtained with the 3 substrates shows that, overall, the acidification of the organic matter and the methanisation of the VFA follow zero order reactions, in the operating conditions of our study. The effect on the gas production rate resulted in two level periods separated by a sharp break when the acidification stage was finished and only the breaking down of the VFA continued.

Selenium, zinc and copper in plasma of patients with type 1 diabetes mellitus in different metabolic control states

The Studies of selenium (Se), zinc (Zn) and copper (Cu) levels in diabetic patients have led to contradictory findings as the possible relationship between the degree of diabetic control and the changes in mineral contents. In the present study the plasma Cu, Se, and Zn contents of diabetic patients and healthy people were measured and the relationship between these contents and diabetic metabolic control, as determined by glycosylated hemoglobin (HbA1c), was studied. The mean plasma Se content in diabetic patients was significantly lower than in controls (p < 0.01) and a negative correlation between the plasma contents of Se and HbA1c was found. No statistically significant differences in plasma Zn contents, either between patients with type 1 diabetes mellitus and control, were found. A statistically significant sex difference in plasma Cu contents was observed in the control population. In females, statistically significant differences were found in plasma Cu contents between the control subjects and the diabetic patients with medium or poor metabolic control, as well as between diabetic patients with good and poor metabolic control. In males, the only statistically significant differences were between the control subjects and diabetic patients with poor metabolic control. The correlation between plasma contents of Cu and HbA1c is not significant.

Scintigraphic findings in a Brodie's abscess

A 9-year-old girl had a 6-month history of left hip pain. Radiographs of the left hip showed a metaphyseal osteolytic lesion with sclerotic borders in the femoral neck. Tc-99m MDP bone imaging and a Ga-67 scan showed focal areas of increased activity in the left femoral neck. These areas of increased uptake corresponded to a lytic area on x-rays, which was due to a Brodie's abscess. The combination of Tc-99m MDP bone and Ga-67 imaging has been widely used in the confirmation of bone infection, increasing the accuracy in the diagnosis of osteomyelitis. However, nuclear scintigraphy has not been previously reported in the confirmation of a Brodie's abscess.

Colovesical fistula secondary to vesical gangrene in a diabetic patient

We present a case of colovesical fistula secondary to vesical gangrene. Precipitating factors were diabetes and vesical distension caused by the obstruction of an indwelling catheter. This complication is an exceptional outcome in gangrenous cystitis and it requires emergency surgical treatment.

Reduced levels of uridine diphosphate glucose pyrophosphorylase activity in fetal and neonatal human and guinea pig liver

Uridine diphosphate glucose pyrophosphorylase (UDPGPP) is the first enzyme in the bilirubin conjugation pathway. A study aiming to screen for red blood cell UDPGPP deficiency in newborns with hyperbilirubinemia was carried out. No individuals with severe UDPGPP deficiency were found, however, levels of UDPGPP in premature and at term newborns were lower than in adults. These findings led to the study of UDPGPP in human fetal, neonatal and adult liver, using guinea pig tissues as a parallel control. UDPGPP activities in fetal and neonatal samples were also significantly lower than in adult ones in both species. Therefore, it is postulated that the reduced levels of UDPGPP in fetal and neonatal liver could be a factor which contributes to the pathogenesis of the physiologic jaundice in human newborns.

[Modification of complement factors and their inhibitors during meningococcal sepsis (author's transl)]

Various complement components (C'1s, C'3, C'4, C'5, C'8, C'9, C'3 act., C'1 inh., C'3b inact.) and seric immunocomplexes (by polyethylene glycol, PEG) were evaluated in 43 children with meningococcal sepsis. 28 patients had disseminated intravascular coagulation (DIC), group I, and 15 did not show it, group II; 14 patients died in group I and none of group II. In 21 cases studies were repeated 24 hours later. In group I all complement components were decreased, specially C'3 (x: 67 mg./100 ml., p < 0.01) and C'5 (x: 8 mg./100 ml., p < 0.01) and they were lower 24 h. later. Results of group II were normal, except a decrease of C'5. Catabolic products of C'3 were founded in 11/14 cases of group I and two/nine of group II and products of C'3 act. in four/14 and one/10. PEG precipitation was positive in 10/14 cases of group I and 10/12 of group II and IgG, IgM, C'3 and C'4 were found in precipitations. This complement components were more frequently present in sepsis without DIC and after 24 h. of evolution. C'1 and C'3b inhibitors decreased after evolution in group I and by contrast increased in group II. This fall enhances complement activation.

[Tuberculous cerebral abscess. Morphopathologic study (author's transl)]

A 73-year-old patient with a cerebral abscess of tuberculous etiology localized in the left parietooccipital region is presented. Clinically it had behaved like an expansive process. The inside of the abscess contained a purulent exudate with polynuclear cells and necrotic material. The wall of the abscess was formed by a predominantly histiocytic internal layer and an external one composed by histiocytes with the morphology of epithelioid cells. No tuberculous granulomas were found. The histiocytes contained a large number of acid-alcohol resistant bacilli. In the exudate Mycobacterium tuberculosis hominis was bacteriologically isolated. After the surgical operation the patient developed an acute tuberculous sepsis with tuberculous exudative meningitis and miliary dissemination in various organs. As regards the pathogenesis of the tuberculous cerebral abscess the authors consider the possible influence of a deficitary immune state of the patient and the aggressiveness of the infective organism.