Engineered lentivirus-derived nanoparticles (LVNPs) for delivery of CRISPR/Cas ribonucleoprotein complexes supporting base editing, prime editing and in vivo gene modification

Implementation of therapeutic in vivo gene editing using CRISPR/Cas relies on potent delivery of gene editing tools. Administration of ribonucleoprotein (RNP) complexes consisting of Cas protein and single guide RNA (sgRNA) offers short-lived editing activity and safety advantages over conventional viral and non-viral gene and RNA delivery approaches. By engineering lentivirus-derived nanoparticles (LVNPs) to facilitate RNP delivery, we demonstrate effective administration of SpCas9 as well as SpCas9-derived base and prime editors (BE/PE) leading to gene editing in recipient cells. Unique Gag/GagPol protein fusion strategies facilitate RNP packaging in LVNPs, and refinement of LVNP stoichiometry supports optimized LVNP yield and incorporation of therapeutic payload. We demonstrate near instantaneous target DNA cleavage and complete RNP turnover within 4 days. As a result, LVNPs provide high on-target DNA cleavage and lower levels of off-target cleavage activity compared to standard RNP nucleofection in cultured cells. LVNPs accommodate BE/sgRNA and PE/epegRNA RNPs leading to base editing with reduced bystander editing and prime editing without detectable indel formation. Notably, in the mouse eye, we provide the first proof-of-concept for LVNP-directed in vivo gene disruption. Our findings establish LVNPs as promising vehicles for delivery of RNPs facilitating donor-free base and prime editing without formation of double-stranded DNA breaks.

[Complications of the adeno-tonsillectomy]

Adeno-tonsillectomy is the most frequent surgical intervention of de the head and neck in paediatrics in the industrialised countries and one of the most common operations in Mayor Day Case Surgery; although is not void of risks which can be fatal. Complications can be surgical or anaesthetics in nature, one of the most serious complications being postoperative bleed. Among risk factors we can highlight: age younger then three, female gender, duration of surgery, incomplete haemostasis, coagulophaties. These could be related to delayed oral intake. Postoperative bleed could not related to technique or haemostasis applied. We carry out a revision of this subject.

Longitudinal growth from the proximal femoral growth centers in the rabbit

We selectively ablated the proximal growth centers of the femur in 3-week-old white New Zealand rabbits to study the contribution of each physis to bone length. The results were compared with the normal growth pattern determined in our previously published study. Growth in 10 femora with ablated greater trochanteric apophyses was normal as was the rate of growth for the 11 femora in which the proximal physis and femoral head were excised. Following femoral head excision, growth of 10 greater trochanteric apophyses, transferred in situ with muscular pedicle, was delayed initially, then increased at a rate very different from the control trochanteric growth. On the basis of this animal study, we support substitution of the greater trochanteric apophysis for an injured femoral neck physis to provide growth in the length of the femur.

Serum concentrations and side effects in psychiatric patients during risperidone therapy

Steady state serum concentrations of risperidone and 9-hydroxyrisperidone (9-OH-risperidone), the active moiety, were measured in 42 patients. The concentration-to-dose ratios (C/D) varied by a factor of 20, from 1.8 to 36.8 (nmol/l)/(mg/24 hours), and 90% of the active moiety was constituted of 9-OH-risperidone. No correlation between the serum concentration of the active moiety and the side effects evaluated by the UKU Side Effect Scale was found. The absence of CYP2D6 (poor metabolizers) or the coadministration of drugs other than benzodiazepines increased the ratio between parent compound and metabolite but did not significantly influence the C/D of the total active moiety. A therapeutic range for serum risperidone has not been established, but 6 mg/day is considered the optimum dose for most patients. The authors found that in 90% of 22 patients administered 6 mg/day risperidone, the serum levels were within 50 to 150 nmol/l.

Radiographic assessment of longitudinal growth of the rabbit femoral physes

Using surgically implanted metal markers, serial radiographs of 17 immature femurs were evaluated for growth of the entire femur and of the distal femoral physis in rabbits 20 to 100 days of age. From these data the rate of longitudinal growth was plotted. The most rapid growth during the study period was from 20 to 40 days. Growth rates reached a plateau at 100 days of age. The increases in length for unit of time were compared for the entire femur and the distal physis. The distal physis was responsible for approximately 65-70% of the femoral growth for the study period. As an internal control of reproducibility of measurement, two means of determining distal femoral growth rates were compared. Their best fit curves proved to be almost identical. The model of evaluation of femoral growth is reproducible and can serve as a control against which variables in growth can be compared.

Ice skating accidents and injuries

A total of 169 consecutive injuries to ice skaters is reviewed. The majority resulted from falls and occurred in young people with little or no previous skating experience. Speed and crowding on the ice may be contributory. Injuries occur because of a casual attitude to the sport and because of a lack of awareness of the potentially serious injuries that can result. It would be beneficial for beginners to undergo specific instruction and, if possible, at separate times or in separate areas.

Detection by replica plating of false revertant colonies induced in the Salmonella-mammalian microsome assay by hexavalent chromium

The replica plating method as developed by Lederberg has been used to differentiate between "true" and "false" histidine-requiring revertant bacterial colonies which develop on minimal agar plates in the Ames test. Strains of S. typhimurium LT2, TA 100, when exposed to either sodium dichromate or the fumes from the welding of stainless steel, develop colonies whose apparent numbers are directly in proportion to the Cr(VI) content per plate in both cases, over a wide dose range. Replica impressions of the resulting colonies were transferred to Vogel Bonner minimal agar plates and incubated for 48 hr at 37 degrees C. It was then observed that considerable numbers of "false" revertant colonies were obtained at those Cr(VI) doses which resulted in a pronounced toxic effect, albeit with an acceptable level of the bacterial background lawn. No morphological distinction between "true" and "false" revertant colonies could be made. Although it would appear that at low doses (i.e., low toxicity) the true mutagenicity of stainless steel welding fumes can be completely accounted for by the presence of Cr(VI), the dose range over which the mutagenicity assay is reliable cannot be estimated from examination of the background lawn or from an estimate of the degree of survival of the treated cultures. Thus there is raised a serious question concerning the reliability of quantitative data published in bacterial mutagenicity testing where replica testing of the histidine requirement of the resulting "revertant" colonies is not routinely made. It is suggested that the replica technique can easily be developed as a simple and useful tool for the control of histidine requirement and ampicillin resistance in routine mutagenicity testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructural immunocytochemical localization of vitellogenin in the fat body of the blowfly, Calliphora vicina Rob.-Desv. (erythrocephala Meig.) by use of the unlabeled antibody-enzyme method

The unlabeled antibody-enzyme method was used to demonstrate ultrastructurally the specific localization of vitellogenin in the fat body of Calliphora. In control flies the binding sites to vitellogenin were localized in secretory granules situated in the Golgi complex, and in larger bodies named composite secretory granules. These composite granules appear to be formed when a part of a Golgi complex containing secretory granules and a number of small vesicles become surrounded by a common membrane. Ovariectomized flies, which apparently do not produce secretory granules, exhibited no immunocytochemical staining. Ovariectomized flies in which the administration of ecdysterone induced formation of secretory granules, also revealed specific staining on these granules. This is the first ultrastructural evidence of: (a) the specific localization of vitellogenin in secretory granules of the fat body of an insect; (b) the relationship between the presence of the ovary, and of ecdysterone, and the synthesis of vitellogenin by the fat body.

A simple analytical technique for the determination of hexavalent chromium in welding fumes and other complex matrices

A systematic study of analytical methods for the determination of hexavalent chromium showed that currently existing techniques are unsatisfactory when used with welding fumes, the s-diphenylcarbazide method proposed by the U.S. National Institute for Occupational Safety and Health permitting less than 1% recovery of hexavalent chromium from synthetic welding fumes of known composition. A new (carbonate leaching) technique is proposed which permits better than 80% recovery of both soluble and insoluble chromium (VI). This technique is then used as part of a general method for the determination of total chemical composition as distributed among sample fractions of different solubility. The method is specifically designed for use in the analysis of small samples and is especially suitable for the routine evaluation of health risks as found in the work environment.

Production of specific-protein secretion granules by fat body cells of the blowfly, Calliphora erythrocephala. Substitution of an ovarian key factor by beta-ecdysone

During the first four days of the imaginal stage the fat cells of ovariectomized females of Calliphora develop a protein synthetic apparatus, and produce dense bodies (lysosomes) as do the fat cells of normal females, but apparently they cannot synthesize the protein secretion granules that characterize the productive phase of the fat cells of normal females and that we believe to represent vitellogenin. Injection of ovariectomized females with beta-ecdysone restored the ability of the fat cells to produce the secretion granules. It is suggested that the ovary gives off a factor which induces the production of the protein secretion granules by the fat cells, and that the factor from the ovary can be substituted by beta-ecdysone. This, we believe, is the first ultrastructural evidence for an effect of the ovary and of beta-ecdysone on the synthesis of specific protein.