From mild to gangrenous cholecystitis, laparoscopic cholecystectomy is safe 24 hours a day

OBJECTIVES

Laparoscopic cholecystectomy (LC) at night remains controversial. Prior studies have not controlled for disease severity. We analyzed outcomes of LC performed day vs. night while controlling for the Parkland Grading Scale for Cholecystitis (PGS).

METHODS

Analysis of the AAST multicenter evaluation of cholecystitis database was performed. Exclusion criteria included non-operative cases, open operations, and missing PGS. Cases were divided based on operation start time. PGS was used to control for disease severity. Outcomes included operative time, use of bailout techniques and complications.

RESULTS

Of 759 procedures identified, 16% were nighttime LC. No differences in demographics, comorbidities, physiologic variables and PGS were noted. Operative time (108.6 min vs 105.6), bailout techniques (8.3% vs 7.4%) and complications (9.9% vs 11.3%) were similar between groups.

CONCLUSION

Regardless of severity, laparoscopic cholecystectomy is safe 24-h a day. Operations performed at night have a similar complication profile to those performed during the day.

Antibody Responses After mRNA-Based COVID-19 Vaccination in Residential Older Adults: Implications for Reopening

Objective

COVID-19 disproportionately impacts residents in long-term care facilities. Our objective was to quantify the presence and magnitude of antibody response in vaccinated, older adult residents at assisted living, personal care, and independent living communities.

Design

A cross-sectional quality improvement study was conducted March 15 – April 1, 2021 in the greater Pittsburgh region.

Setting and Population

Participants were older adult residents at assisted living, personal care, and independent living communities, who received mRNA-based COVID-19 vaccine. Conditions that impair immune responses were exclusionary criteria.

Methods

Sera were collected to measure IgG anti-SARS-CoV-2 antibody level with reflex to total anti-SARS-CoV-2 immunoglobulin levels, and blinded evaluation of SARS-CoV-2 pseudovirus neutralization titers. Descriptive statistics, Pearson correlation coefficients, and multiple linear regression analysis evaluated relationships between factors potentially associated with antibody levels. Spearman correlations were calculated between antibody levels and neutralization titers.

Results

All participants (N = 70) had received two rounds of vaccination and were found to have antibodies with wide variation in relative levels. Antibody levels trended lower in males, advanced age, current use of steroids, and longer length of time from vaccination. Pseudovirus neutralization titer levels were strongly correlated (P < .001) with Beckman Coulter antibody levels [D614 G NT50, r_s = 0.91; B.1.1.7 (UK) NT50, r_s = 0.91].

Conclusions and Implications

Higher functioning, healthier, residential older adults mounted detectable antibody responses when vaccinated with mRNA-based COVID-19 vaccines. Data suggests some degree of immunity is present during the immediate period following vaccination. However, protective effects remain to be determined in larger studies as clinical protection is afforded by ongoing adaptive immunity, which is known to be decreased in older adults. This study provides important preliminary results on level of population risk in older adult residents at assisted living, personal care, and independent living communities to inform reopening strategies, but are not likely to be translatable for residents in nursing homes.

The tissue distribution and functional characterization of human VR1

The irritant action of capsaicin is mediated by the vanilloid receptor, VR1, which is expressed in sensory neurons termed nociceptors. Capsaicin also desensitizes nociceptors and, thus, is useful clinically as an analgesic. Given the potential importance of VR1 in pain, we have cloned the human capsaicin receptor, hVR1, from a human dorsal root ganglia (DRG) cDNA library. Human VR1 protein is 85% identical to the rat VR1 and many of the amino acid differences are concentrated at the amino and carboxyl termini. VR1 is expressed in DRG as an approximately 4.2 kilobase RNA, and is also expressed in the central nervous system and in the kidney. Capsaicin (EC(50) = 853 nM), low pH (<5.5), and noxious heat (44 degrees C) activate hVR1 expressed in Xenopus oocytes. Subthreshold pH (6.4) sensitizes VR1 to capsaicin (EC(50) = 221 nM). This study demonstrates the similarity of human and rat VR1 in integrating multiple noxious stimuli.

Segregation of proteinase-negative mutants from heterozygous Candida albicans

The extracellular acidic proteinase (EC 3.4.23.6) produced by Candida albicans has been reported to be a virulence factor. In studying the role of this proteinase in human disease, we determined the optimum conditions for stimulating proteinase production in order to isolate proteinase-negative (Prt-) mutants. We found that in liquid medium containing bovine serum albumin (BSA) as the sole nitrogen source, at pH 4 and 27 degrees C, the sensitivity of proteinase detection was considerably greater than when assayed on BSA agar at 37 degrees C. This observation is due, in part, to temperature sensitivity of proteinase induction. Nitrogen starvation did not induce proteinase. Proteinase production on agar was increased by adding 0.01% yeast extract (YE) to BSA medium. Using BSA + YE agar to isolate mutants, it was discovered that C. albicans ATCC 28366 was heterozygous for a Prt- mutation. Spontaneous Prt- mutants occurred at a frequency of 2 x 10(-3). Ultraviolet light increased the mitotic segregation of Prt- cells to a frequency of 1 x 10(-2). The Prt- phenotype showed a large inoculum effect, Prt- segregants reverted with a high frequency, and the revertants were unstable.

Sporulation in Hansenula wingei is induced by nitrogen starvation in maltose-containing media

The sexually agglutinative yeast Hansenula wingei lives in association with bark beetles that inhabit coniferous trees. This yeast was induced to sporulate by malt extract, which contains a high percentage of maltose (50%) and a low percentage of nitrogen (0.5%). A solution of 1.5% maltose without any growth factors also induced ascosporogenesis in H. wingei. Thus, only a carbon source is required for sporulation as in Saccharomyces. However, potassium acetate did not induce sporulation in H. wingei as it does in S. cerevisiae. Instead, disaccharides (such as maltose, sucrose, or cellobiose) promote sporulation better than either monosaccharides (such as dextrose, fructose, or mannose) or respiratory substrates (such as ethanol or glycerol). The specificity of disaccharides in promoting sporulation in H. wingei may be considered an adaptation since these disaccharides are present in the natural environment of this yeast. In addition, the specificity of disaccharides may be related to the induction of the disaccharidase because cells precultured on dextrose sporulate well on maltose, but cells precultured on maltose sporulate poorly on maltose. When (NH(4))(2)SO(4) was added at a low concentration (3 mM) to synthetic sporulation medium (1.5% maltose solution), sporulation was abolished, whereas other salts and nitrogen sources inhibited to a lesser extent and vitamins and trace elements had no effect. Oxygen was required for sporulation, as expected for an obligate aerobe. Maximal sporulation was achieved in 2% malt extract broth at high cell density (10(9) cells per ml), pH 5, and 25 degrees C. By using these optimal physiological conditions and hybrid strains selected from an extensive genetic breeding program, about 30% asci (10% tetrads) were obtained routinely. Thus, the genetics of cell recognition in this yeast can now be studied.

RARE-CELL FUSION EVENTS BETWEEN DIPLOID AND HAPLOID STRAINS OF THE SEXUALLY AGGLUTINATIVE YEAST HANSENULA WINGEI

Diploids of the yeast Hansenula wingei are nonagglutinative and do not form zygotes in mixed cultures with either sexually agglutinative haploid mating type. However, a low frequency of diploid x haploid cell fusions (about 10-3) is detectable by prototrophic selection. This frequency of rare diploid x haploid matings is not increased after the diploid culture is induced for sexual agglutination. Therefore, we conclude that genes that repress mating are different from those that repress sexual agglutination.——Six prototrophs isolated from one diploid x haploid cross had an average DNA value (¼g DNA per 108 cells) of 6.19, compared to 2.53 and 4.35 for the haploid and diploid swains, respectively. Four prototrophs were clearly cell-fusion products because they contained genes from both the diploid and the haploid partners. However, genetic analysis of the prototrophs yielded results inconsistent with triploid meiosis; all six isolates yielded a 2:2 segregation for the mating-type alleles and linked genes.——Mitotic segregation of monosomic (2n-1) cells lacking one homolog of the chromosome carrying the mating-type locus is proposed to explain the rare production of sexually active cells in the diploid cultures. Fusion between such monosomic cells and normal haploids is thought to have produced 3n-1 cells, disomic for the chromosome carrying the mating-type locus. We conclude that in the diploid strain we studied, the physiological mechanisms repressing sexual agglutination and conjugation function efficiently, but events occurring during mitosis lead to a low frequency of genetically altered cells in the population.

Microtiter plate assay for sexual agglutination in the yeast Hansenula wingei

A fast method is described for determining the mating type of yeast spore clones independent of genetic complementation between auxotrophic markers.

Alternaria IgG precipitins and adverse reactions

Late reactions consisting of fever, malaise, and swelling at the site, 4 to 6 hr after injections of Alternaria extract occurred in several patients receiving immunotherapy with Alternaria. These patients had in common serum IgG precipitins and exquisite leukocyte histamine release sensitivity to Alternaria. Such precipitins were 3 times more frequent in patients receiving Alternaria immunotherapy than a control group of patients receiving immunotherapy with other antigens. A prospective study revealed that 5 of 23 Alternaria-sensitive persons had precipitins before immunotherapy and another 6 developed precipitins during therapy. Only one of the 23 experienced a late Alternaria reaction. Thus, precipitins to Alternaria are common and do not seem to be the basis for the late reactions we observed. The finding of precipitins does not contraindicate immunotherapy.

Molecular complementarity of yeast glycoprotein mating factors

Cell fusion between opposite mating types 5 and 21 of the yeast Hansenula wingei is initiated by a strong sexual agglutination reaction. The mating factors responsible for the specificity of cellular recognition are complementary glycoproteins which form a physical complex in vitro. The complex is assayed by recovery of agglutination activity of the multivalent 5-factor after the univalent 21-factor has been inactivated by treatment of the complex with alkali. The 5-factor.21-factor complex, purified on Sepharose 6B, is large (several million daltons) and heterogeneous. The three peaks of 5-factor activity contain a number of combining sites proportional to molecular size.

The chromosome number of the yeast Hansenula wingei observed in mitosis and meiosis

Four chromosomes were observed at mitosis in haploid as well as diploid strains and four bivalents were observed at meiosis in the diploid. Therefore it is assumed that a) the haploid number of chromosomes in H. wingei is four and b) somatic pairing occurs in the diploid.

Temperature-sensitive mutants of Escherichia coli affecting beta-galactoside transport

Six different temperature-sensitive (ts) mutants have been isolated which have parental beta-galactoside permease levels at low temperatures but have decreased permease levels when grown at high temperatures. These mutants were derived from Escherichia coli ML308 (lacI(-)Y(+)Z(+)A(+)). After N-methyl-N'-nitro-N'-nitro-soguanidine mutagenesis, ampicillin was used to select for cells unable to grow on low lactose concentrations at 42 C. Temperature-sensitive mutants were assayed for galactoside permease activity after growth in casein hydrolysate medium at 25 or 42 C by measuring both radioactive methylthio-beta-d-galactoside uptake and in vivo o-nitrophenyl-beta-d-galactoside hydrolysis. The six conditional isolates have decreased levels of galactoside permease which are correlated with decreased growth rates at elevated temperatures. The low permease levels are not due to a temperature labile lacY gene product but rather to a temperature labile synthesis rate of functional permease. Some of the mutants exhibit a ts increase in permeability as shown by the increased leakage of intracellular beta-galactosidase and by the increased rate of in vivo o-nitrophenyl-beta-d-galactoside hydrolysis via the nonpermease mediated entry mechanism. Preliminary evidence indicates that transport in general is decreased in these mutants, yet there is some specificity in the mutational lesion since glucoside transport is unaffected. All these observations suggest that these mutants have ts alterations in membrane synthesis which results in pleiotropic effects on various membrane functions.