Target-dependent axonal sprouting following vagal-hypoglossal nerve anastomosis in cats

Purpose: To investigate the relationships between the axonal sprouting and target neurotization by central neurons after nerve heterocon-nection. Methods: Unilateral (right) vagal-hypoglossal nerve anastomosis (VHA) was performed in adult cats. Following 3-315 days postoperation (dpo), quantitative analyses and ultrastructural changes in the proximal portion of the vagal-hypoglossal heteroconnected nerve as well as the time course of neuronal regeneration were studied. Along with this, horseradish peroxidase (HRP) retrograde tracing technique was used to label the neurons of dorsal motor vagal nucleus (DMV) and nucleus ambiguus (NA) to ascertain if target neurotization was established. Results: The contralateral (left) intact vagus nerve proximal to the level of ansa cervicalis showed an average of 33 +/- 1 myelinated and 74 +/- 4 unmyelinated axons in 727 &mgr;m(2) sectional area of the nerve. In the heteroconnected nerve at the corresponding level just proximal to the anastomosis site, there was a marked increase in the number of small axons sprouting from the unmyelinated nerve fibers between 18 and 25 dpo. The number of these axonal sprouts appeared to decline at 32 dpo but its increase of 131 % was sustained until the late regeneration stage at 315 dpo when compared with the contralateral nerve serving as a control. The mean number of myelinated axons per area unit (727 &mgr;m(2)) was reduced to 18 at 3 dpo but was immediately restored to the normal range at 7 dpo. The retrograde labelling of neurons in both the DMV and NA was first detected at 22 dpo and was progressively increased peaking by about 67 dpo. Conclusions: We conclude that compared with the unmyelinated axons, the myelinated axons may acquire a superior interaction with the new target. Furthermore, the postoperative neurotization of tongue muscles may initiate and facilitate the retraction of the redundant axonal sprouts.     

Coronavirus Disease Contact Tracing Outcomes and Cost,Salt Lake County,Utah, USA,March–May 2020

Outcomes and costs of coronavirus disease (COVID-19) contact tracing are limited. During March–May 2020, we constructed transmission chains from 184 index cases and 1,499 contacts in Salt Lake County, Utah, USA, to assess outcomes and estimate staff time and salaries. We estimated 1,102 staff hours and $29,234 spent investigating index cases and contacts. Among contacts, 374 (25%) had COVID-19; secondary case detection rate was ≈31% among first-generation contacts, ≈16% among second- and third-generation contacts, and ≈12% among fourth-, fifth-, and sixth-generation contacts. At initial interview, 51% (187/370) of contacts were COVID-19–positive; 35% (98/277) became positive during 14-day quarantine. Median time from symptom onset to investigation was 7 days for index cases and 4 days for first-generation contacts. Contact tracing reduced the number of cases between contact generations and time between symptom onset and investigation but required substantial resources. Our findings can help jurisdictions allocate resources for contact tracing.     

Hand-assisted Laparoscopic Colorectal Surgery: Initial Experience of a Single Surgeon

Background/Aim:

As totally laparoscopic colorectal surgery is considered challenging and technically demanding with a long steep learning curve, we adopted hand-assisted laparoscopic colorectal surgery as a bridge to totally laparoscopic assisted colorectal surgery. This prospective study aims to highlight the initial experience of a single surgeon with this technique.

Materials and Methods:

A prospective analysis of the first 25 cases of hand-assisted laparoscopic colorectal resections which were performed by a single surgeon over a 15-month period. There were 15 males and 10 females with a mean age of 55.5 (range 20-82) years.

Results:

The indication in majority of cases was cancer (76%). The procedures consisted of 18 (72%) various colectomies and 7 (28%) anterior resections. The operative time ranged between 110-400 (mean 180) min. There was one conversion (4%) and the mean operative blood loss was 80 (range 60-165) ml. The number of lymph nodes retrieved in the cancer cases was 5-31 (mean 15) nodes. The mean length of hospital stay was five (range 3-10) days. The total number of short-term complications was six (24%) and there was one death due to anastomatic leak and multiorgan failure. Long-term complications after a maximum follow up of 30 months were two incisional hernias at the hand port site, but none of the patients developed adhesive small bowel obstruction or late anastomotic stricture. Currently all our colorectal procedures are conducted laparoscopically.

Conclusion:

Hand-assisted laparoscopic colorectal procedures are easy to learn as a good bridge to master totally laparoscopic colorectal surgery.     

Vitamin E status among bariatric surgery patients: a systematic review

Vitamin E, a fat-soluble vitamin with antioxidant properties, is thought to modulate enzymes involved in signal transduction, affect gene expression, and have immunomodulatory capabilities. Severe vitamin E deficiency is associated with neuronal disorders, impaired immune response, hemolytic anemia, and oxidative-based disorders. Patients who undergo bariatric surgery (BS), especially malabsorptive procedures, are at greater risk of developing fat-soluble vitamin deficiencies. Current data on vitamin E statuses among BS patients are limited. Therefore, this systematic review has summarized the scientific literature on vitamin E and examined its status among patients following different types of BS. Searches of the MEDLINE and Embase databases were performed, followed by hand-searching of reference lists from all relevant papers. Of the 671 initially identified articles, 24 met the inclusion criteria: 1 study on adjustable gastric banding patients (n = 21), 4 studies on sleeve gastrectomy patients (n = 173), 12 studies on Roux-en-Y gastric bypass patients (n = 689) and 12 studies on biliopancreatic diversion with or without duodenal switch (n = 799) or single anastomosis duodeno-ileal bypass with sleeve gastrectomy patients (n = 163). Results suggest that patients who undergo malabsorptive procedures are at higher risk of developing vitamin E deficiency, although clinical manifestations of vitamin E deficits following BS are rarely documented. The optimal dose of vitamin E supplementation required for prevention of deficiency or for treatment following BS has yet to be established. Future observational and intervention studies are needed to bridge the gaps in existing knowledge.     

Hepatic cryotherapy for liver tumors

A high-efficiency hepatic cryosurgical unit has been developed and evaluated. It is capable of simultaneously driving three implantable insulated cryoneedle probes. The system has been used to treat 18 patients with secondary and 4 patients with primary liver cancer: open (n=12), total laparoscopic (n=6), laparoscopic assisted (n=4). In three patient laparoscopic cryotherapy was repeated inside 6 months.Intraoperative bleeding was encountered in three patients undergoing high-volume hepatic freezing but the bleeding was easily controlled. A fall in the core body temperature was encountered in 10 out of 22 patients and averaged 0.4°;C. There was one postoperative death from liver failure in an 80-year-old patient in whom a large hepatoma was frozen. The most consistent postoperative biochemical change was hyperbilirubinaemia (n=3). A right-sided pleural effusion developed in two patients after freezing of lesions on the superior surface of the right lobe.A survival benefit was encountered in three patients, one with central cholangiocarcinoma and the other two with large solitary secondary deposits (melanoma, colon cancer). Seven patients with multiple metastases and two patients with large hepatomas developed recurrence at the frozen site or elsewhere in the liver inside 12 months of follow-up and no clinical benefit could be demonstrated by cryotherapy in this group. In nine patients, the follow-up has been too short (<18 months) to permit any conclusion on outcome. The current limitations of hepatic cryotherapy are largely due to incomplete tumor destruction. The use of insulated laparoscopic cryoprobes which can be positioned under visual control through the parietes in the optimal site for maximal tumor ablation should enhance the therapeutic efficiency of cryotherapy for both primary and secondary hepatic tumors.     

Health and Nutritional Status of Vegetarian Candidates for Bariatric Surgery and Practical Recommendations

Introduction

Data on vegetarianism and bariatric surgery (BS) are scarce. We herein describe the health and nutritional status of vegetarian patients who plan to undergo BS and propose combined recommendations for vegetarian patients who undergo BS, based on our clinical experience and current scientific literature in both nutrition fields.

Methods

Cross-sectional analysis of a prospectively maintained database of all primary laparoscopic sleeve gastrectomies (LSG) performed at a bariatric center of excellence between January 2014 and November 2016 was carried out querying patients who declared a vegetarian or vegan lifestyle before surgery. Preoperative data collected included demographics, anthropometrics, dietary patterns, supplementation use, physical activity, smoking habits, co-morbidities, and blood tests. Each vegetarian was matched to five different omnivores based on age, gender, and BMI.

Results

During the study period, 1470 patients underwent primary LSG surgery (63.7% females). Twenty-one declared a vegetarian or vegan lifestyle (1.4%) pre-surgery. Most were classified as lacto-ovo (57.1%) and were driven from ethical reasons (85.7%). No differences were found between vegetarian and omnivore LSG candidates regarding co-morbidities and nutritional deficiencies, except for lower prevalence of impaired fasting glucose (14.3 vs. 47.1%;P = 0.007), lower ferritin levels (54.3 ± 50.5 vs. 96.8 ± 121.8 ng/ml; P = 0.052) and higher transferrin levels (313.9 ± 42.7 vs. 278.4 ± 40.4 mg/dl; P = 0.009) among the vegetarian cohort. Preoperative use of vitamin B12 and iron supplementation was higher among vegetarian LSG candidates than their omnivore counterparts (57.1 vs. 6.7%;P < 0.001 and 23.8 vs. 6.7%; P = 0.015, respectively).

Conclusions

Vegetarians have comparable health status and nutritional deficiencies, lower iron stores, and higher supplementation use before surgery compared to omnivore LSG candidates.

     

Streptomyces as host for recombinant production of Mycobacterium tuberculosis proteins

The 45/47 kDa APA protein (Rv1860) of Mycobacterium tuberculosis was produced by Streptomyces lividans. The recombinant protein could be recovered from the culture medium of an S. lividans clone containing the apa gene under control of the promoter and signal sequence of the Streptomyces coelicolor agarase gene. The recombinant protein production was further scaled-up using fermentation conditions. The APA protein was subsequently purified from the culture supernatant by means of immunochromatography. About 80 mg of recombinant protein were obtained per liter of culture media. In vivo tests with the APA protein purified from S. lividans TK24/pRGAPA1 revealed that the recombinant protein was antigenic and could induce high titers of specific antibodies in the mouse biological model. Results obtained concerning heterologous production of APA, its immunogenic and antigenic capacity, demonstrated the potential of S. lividans as a valuable host for the production of recombinant proteins from M. tuberculosis.