Sweat analysis with a wearable sensing platform based on laser-induced graphene

The scientific community has shown increasing interest in laser scribing for the direct fabrication of conductive graphene-based tracks on different substrates. This can enable novel routes for the noninvasive analysis of biofluids (such as sweat or other noninvasive matrices), whose results can provide the rapid evaluation of a person's health status. Here, we present a wearable sensing platform based on laser induced graphene (LIG) porous electrodes scribed on a flexible polyimide sheet, which samples sweat through a paper sampler. The device is fully laser manufactured and features a two layer design with LIG-based vertical interconnect accesses. A detailed characterization of the LIG electrodes including pore size, surface groups, surface area in comparison to electroactive surface area, and the reduction behavior of different LIG types was performed. The bare LIG electrodes can detect the electrochemical oxidation of both uric acid and tyrosine. Further modification of the surface of the LIG working electrode with an indoaniline derivative [4-((4-aminophenyl)imino)-2,6-dimethoxycyclohexa-2,5-dien-1-one] enables the voltammetric measurement of pH with an almost ideal sensitivity and without interference from other analytes. Finally, electrochemical impedance spectroscopy was used to measure the concentrations of ions through the analysis of the sweat impedance. The device was successfully tested in a real case scenario, worn on the skin during a sports session. In vitro tests proved the non-cytotoxic effect of the device on the A549 cell line.

Non-ohmic behavior and resistive switching of Au cluster-assembled films beyond the percolation threshold

Networks based on nanoscale resistive switching junctions are considered promising for the fabrication of neuromorphic computing architectures. To date random networks of nanowires, nanoparticles, and metal clusters embedded in a polymeric matrix or passivated by shell of ligands or oxide layers have been used to produce resistive switching systems. The strategies applied to tailor resistive switching behavior are currently based on the careful control of the volume fraction of the nanoscale conducting phase that must be fixed close to the electrical percolation threshold. Here, by blending laboratory and computer experiments, we demonstrate that metallic nanostructured Au films fabricated by bare gold nanoparticles produced in the gas phase and with thickness well beyond the electrical percolation threshold, show a non-ohmic electrical behavior and complex and reproducible resistive switching. We observe that the nanogranular structure of the Au films does not evolve with thickness: this introduces a huge number of defects and junctions affecting the electrical transport and causing a dynamic evolution of the nanoscale electrical contacts under the current flow. To uncover the origin of the resistive switching behavior in Au cluster-assembled films, we developed a simple computational model for determining the evolution of a model granular film under bias conditions. The model exploits the information provided by experimental investigation about the nanoscale granular morphology of real films. Our results show that metallic nanogranular materials have functional properties radically different from their bulk counterparts, in particular nanostructured Au films can be fabricated by assembling bare gold clusters which retain their individuality to produce an all-metal resistive switching system.

Enhanced recovery pathways in colorectal surgery: a consensus paper by the Associazione Chirurghi Ospedalieri Italiani (ACOI) and the PeriOperative Italian Society (POIS)

Enhanced Recovery After Surgery (ERAS) pathway is a multi-disciplinary, patient-centered protocol relying on the implementation of the best evidence-based perioperative practice. In the field of colorectal surgery, the application of ERAS programs is associated with up to 50% reduction of morbidity rates and up to 2.5 days reduction of postoperative hospital stay. However, widespread adoption of ERAS pathways is still yet to come, mainly because of the lack of proper information and communication. Purpose of this paper is to support the diffusion of ERAS pathways through a critical review of the existing evidence by members of the two national societies dealing with ERAS pathways in Italy, the PeriOperative Italian Society (POIS) and the Associazione Italiana Chirurghi Ospedalieri (ACOI), showing the results of a consensus development conference held at Matera, Italy, during the national ACOI Congress on June 10, 2019.

Bottom-up engineering of the surface roughness of nanostructured cubic zirconia to control cell adhesion

Nanostructured cubic zirconia is a strategic material for biomedical applications since it combines superior structural and optical properties with a nanoscale morphology able to control cell adhesion and proliferation. We produced nanostructured cubic zirconia thin films at room temperature by supersonic cluster beam deposition of nanoparticles produced in the gas phase. Precise control of film roughness at the nanoscale is obtained by operating in a ballistic deposition regime. This allows one to study the influence of nanoroughness on cell adhesion, while keeping the surface chemistry constant. We evaluated cell adhesion on nanostructured zirconia with an osteoblast-like cell line using confocal laser scanning microscopy for detailed morphological and cytoskeleton studies. We demonstrated that the organization of cytoskeleton and focal adhesion formation can be controlled by varying the evolution of surface nanoroughness.

Considering the implication of variations within Delphi research

Delphi research is an increasingly popular method within medical, social and psychological research. It tends to be employed where established theory or knowledge are lacking but where 'experts' are thought to hold relevant information. It consists of developing and administering sequential questionnaires that seek to move towards a position of relative consensus. Although the original authors of the technique established a specific method, the literature reveals modifications in the way this is applied. Variations include (i) restricting the ability of experts to respond to the original question, (ii) changing or varying the expert groups used and (iii) the point at which the research ends. This paper provides an overview of the technique and explains these variations and their implications before highlighting possible ways forward.

Trend of incidence, subsite distribution and staging of colorectal neoplasms in the 15-year experience of a specialised cancer registry

BACKGROUND

Two-thirds of colorectal malignancies are localised in the left colon and rectum. Recent studies suggest a trend towards an increase of right-sided tumours which might have important implications for screening and surveillance. A colorectal cancer registry was set up in Modena, northern Italy, with the purpose of examining incidence, subsite distribution and staging of colorectal malignancies over a 15-year period.

PATIENTS AND METHODS

From 1984 to 1998, 2517 tumours in 2462 patients were detected and staged with the tumour node metastasis (TNM) system. The 'right colon' was considered from caecum to splenic flexure; the 'left colon' included descending and sigmoid colon; and the 'rectum' included rectosigmoid junction, ampulla and anus.

RESULTS

Cancer incidence showed an overall increase. Considering the various subsites, an increase of 33.7% in all colonic segments was shown whereas rectal tumours tended to decline. TNM staging showed a gradual increase of localised lesions (41.2% in 1984 versus 53.3% in 1998), with a proportional reduction of advanced tumours.

CONCLUSIONS

Our study indicates an increase of tumour incidence in all colonic segments more than a shift to the right colon. TNM staging tended to improve with an appreciable increase of localised lesions. These findings could be consequent to a more extensive use of colonoscopy.

Primary paraganglioma of the thyroid gland

We describe the case of a 46-yr-old euthyroid woman, who was submitted to right lobectomy plus isthmusectomy because of a 30 mm large, rapidly growing thyroid nodule. Two cytological examinations of fine needle aspiration biopsy (FNAB) specimens were not diagnostic. Histology showed a neoplasm composed of nests of chief cells, almost completely replacing thyroid parenchyma, infiltrating the capsule and surgical resection margins, and invading perithyroid tissues. Immunohistochemical analysis revealed that the tumor stained positively to chromogranin, synaptophysin, NSE, S-100 protein and tyrosine hydroxylase, whereas no immunoreactivity was detected against cytokeratin, thyroglobulin, TTF-1, calcitonin and CEA. A diagnosis of thyroid paraganglioma (PG) was finally made. No complications developed following operation. Laboratory analysis and imaging study excluded multicentric disease, metastases to neck or extracervical organs, and multiple endocrine neoplasia (MEN). We report this unusual case, underscore its clinical and immunohistochemical features and discuss differential diagnosis.

Genetic testing among high-risk individuals in families with hereditary nonpolyposis colorectal cancer

Hereditary nonpolyposis colorectal cancer (HNPCC) is frequently associated with constitutional mutations in a class of genes involved in DNA mismatch repair. We identified 32 kindreds, with germline mutations in one of three genes hMSH2, hMLH1 or hMSH6. In this study, we purposed to evaluate how many high-risk individuals in each family underwent genetic testing: moreover, we assessed how many mutation-positive unaffected individuals accepted colonoscopic surveillance and the main findings of the recommended follow-up. Families were identified through a population-based registry, or referred from other centres. Members of the families were invited for an education session with two members of the staff. When a kindred was consistent with HNPCC, neoplastic tissues were examined for microsatellite instability (MSI) and immunohistochemical expression of MSH2, MLH1 and MSH6 proteins. Moreover, constitutional mutations were searched by SSCP or direct sequencing of the whole genomic region. Of the 164 subjects assessed by genetic testing, 89 were gene carriers (66 affected - that is, with HNPCC-related cancer diagnosis - and 23 unaffected) and 75 tested negative. Among the 23 unaffected gene carriers, 18 (78.3%) underwent colonoscopy and four declined. On a total of 292 first degree at risk of cancer, 194 (66.4%) did not undergo genetic testing. The main reasons for this were: (a) difficulty to reach family members at risk, (b) lack of collaboration, (c) lack of interest in preventive medicine or 'fatalistic' attitude towards cancer occurrence. The number of colorectal lesions detected at endoscopy in gene carriers was significantly (P<0.01) higher than in controls (noncarriers). We conclude that a large fraction of high-risk individuals in mutation-positive HNPCC families does not undergo genetic testing, despite the benefits of molecular screening and endoscopic surveillance. This clearly indicates that there are still barriers to genetic testing in HNPCC, and that we are unable to provide adequate protection against cancer development in these families.

Aetiology of colorectal cancer and relevance of monogenic inheritance

BACKGROUND AND AIMS

Although diet and lifestyle are associated with the development of colorectal malignancies, the only clearly identified aetiological factors in colorectal cancer are inheritance (hereditary non-polyposis colorectal cancer (HNPCC) and familial polyposis), inflammatory bowel diseases, papillomavirus, and acquired immunodeficiency syndrome (AIDS). Our aim was to determine what proportion of colorectal neoplasms could be attributed to these specific factors.

PATIENTS AND METHODS

Data from a colorectal cancer registry were analysed over a 15 year period, during which nearly 2500 cases were recorded. In patients with suspected HNPCC, microsatellite instability and immunohistochemical expression of proteins encoded by the main DNA mismatch repair genes were assessed. In families with unstable neoplasms, constitutional mutations of the mismatch repair genes hMSH2, hMLH1, and hMSH6 were evaluated by single strand conformation polymorphism analysis and sequencing.

RESULTS

Inflammatory bowel diseases, familial polyposis, and AIDS were rare causes of colorectal cancer (three, three, and one case, respectively). Anal squamous carcinoma developed in 27 patients (1.0%) and could be attributed to papillomavirus infection. In 58 patients (from 34 families) a clinical diagnosis of HNPCC was established (2.4%). In total, cases with a known aetiology were 92 (3.7% of all patients). Microsatellite instability was detected in 15 cancers from HNPCC families, and germline mutations in six families (12 patients, 0.5% of the total). Families with unstable tumours, with or without mutations, were clinically similar, suggesting the involvement of the mismatch repair system even when mutations were not detected.

CONCLUSIONS

The study suggests that the aetiology of colorectal malignancies remains elusive in the large majority of cases. Among specific causes, HNPCC represents the most frequent. However, with a population based approach, constitutional mutations of the main genes involved in HNPCC can be detected in only 20% of cases.

Molecular screening for hereditary nonpolyposis colorectal cancer: a prospective, population-based study

PURPOSE

Germline mutations in mismatch repair genes predispose to hereditary nonpolyposis colorectal cancer (HNPCC). To address effective screening programs, the true incidence of the disease must be known. Previous clinical investigations reported estimates ranging between 0.5% and 13% of all the colorectal cancer (CRC) cases, whereas biomolecular studies in Finland found an incidence of 2% to 2.7% of mutation carriers for the disease. The aim of the present report is to establish the frequency of the disease in a high-incidence area for colon cancer.

PATIENTS AND METHODS

Through the data of the local CRC registry, we prospectively collected all cases of CRC from January 1, 1996, through December 31, 1997 (N = 391). Three hundred thirty-six CRC cases (85.9% of the incident cases) were screened for microsatellite instability (MSI) with six to 12 mono- and dinucleotide markers. MSI cases were subjected to MSH2 and MLH1 germline mutation analysis and immunohistochemistry; the methylation of the promoter region was studied for MLH1.

RESULTS

Twenty-eight cases (8.3% of the total) showed MSI. MSI cases differed significantly from microsatellite-stable (MSS) cases for their proximal location (P <.01), high mucinous component (P <.01), and poor differentiation (P =.002). Of MSI cases studied (n = 12), only one with a family history compatible with HNPCC had a germline mutation (in MSH2). Five other patients with a family history of HNPCC (two with MSI and three with MSS tumors) did not show germline mutations.

CONCLUSION

We conclude that the incidence of molecularly confirmed HNPCC (one [0.3%] of 336) in a high-incidence area for CRC is lower than in previous biomolecular and clinical estimates.

Clinical and biologic heterogeneity of hereditary nonpolyposis colorectal cancer

MMR gene mutations and MSI are not found in all clinically diagnosed HNPCC families. We evaluated whether MMR genotyping and tumor MSI analysis could identify distinct clinical subgroups among HNPCC families. Twenty-nine clinical HNPCC families were divided into 3 groups: A, families with hMLH1 or hMSH2 gene mutations; B, MMR gene mutations not present but MSI present in at least 50% of tumors tested; C, mutational and MSI analyses negative. We evaluated tumor spectrum, age at onset, risk of cancer in the follow-up and survival for CRC in the 3 groups. Tumors of the target organs in HNPCC (colon and rectum, endometrium, ovary, small bowel, stomach, renal pelvis and ureter) were more frequent in the first 2 groups than in the latter. Colon cancer was more frequently located in the proximal colon and showed an earlier age at onset in families with MMR gene mutation or with MSI than in families with stable tumors. Comparing the occurrence of tumors in the follow-up, in the first 2 groups patients younger than 50 years had a higher RR, which was particularly marked for CRC (RR = 18.6 for group A vs. group C, RR = 16.7 for group B vs. group C). CRC patients in the first 2 groups had a better clinical prognosis. The results of molecular analysis could distinguish, within clinically defined HNPCC families, different subgroups to which specific programs of surveillance could be addressed.

Methylation pattern of different regions of the MLH1 promoter and silencing of gene expression in hereditary and sporadic colorectal cancer

Nonrandom, widespread promoter methylation of tumor suppressor genes is a common mechanism of gene inactivation during tumorigenesis. We examined the methylation status of two distinct regions of the MLH1 promoter (proximal and distal to the transcription start site) and the MLH1 gene expression by methylation-specific PCR and immunohistochemistry. A total of 72 colorectal tumors, both with (n = 51, 22 affected by hereditary nonpolyposis colorectal cancer, HNPCC, defined according to the international clinical criteria and 29 sporadic cases) and without microsatellite instability (MSI) (n = 21) were studied. Methylation was present in at least one of the two promoter regions in 86% of the sporadic MSI cases, in 33% of the cases lacking MSI, and in 23% of the HNPCC tumors. In the HNPCC cases with a known MLH1 mutation (n = 10) none of the two promoter regions was methylated. Hypermethylation in both MLH1 promoter regions was seen in 45% of the MSI sporadic cases vs. 5% of the MSI-negative cases and 0% of the HNPCC cases. The overall concordance between the two promoter regions regarding methylation status was good (P = 0.009), but no significant correlation between methylation and suppression of the MLH1 immunohistochemical expression was found. Our data confirm that mutation and hypermethylation are mutually exclusive mechanisms in inducing mismatch repair deficiency and support the hypothesis of methylation as a process evenly distributed along the different regions of the promoter.

The development of the suprarenal gland: surgical and anatomical considerations

BACKGROUND

Aim of this research is to study the situation and relationships of the adrenal gland in the first stage of development in order to give some contributes for the application of laparoscopic adrenalectomy; in the meantime we describe the series of the debate changes occurring in the constitution of the cortex and medulla.

METHODS

Analysis of histologic slices of thoraco-abdominal and abdominal regions of human embryos and fetuses ranging from the fifth (12 mm CR) to the twentieth week (170 mm CR).

RESULTS

At 12 mm CR an unique type of cells is present in the cortex; at 16 mm CR there are two different groups of cells. Sympathogonia enter into the cortex at 16 mm CR. The right adrenal gland seems enclosed into the liver and a ligament containing the middle adrenal vein reaches the vena cava inferior sulcus. The left adrenal gland, through the coelomic cavity, is in relationship with the stomach, the medial border of the spleen and the pancreatic body contained in the primitive dorsal mesogastrium.

CONCLUSIONS

The timing of penetration of the ganglion cells into the cortex is defined as well as the hypothesis that the matrix of the fetal and definitive cortex is the same: moreover the study of the early development allows to understand the main characteristics of both the adrenal glands which are significant for a rational and differential laparoscopic approach.

Microsatellite instability and mismatch-repair protein expression in hereditary and sporadic colorectal carcinogenesis

Aberrant crypt foci (ACF) are microscopic clusters of altered colonic crypts considered premalignant lesions in the large bowel. Genomic instability at short tandem repeats in the DNA, referred to as microsatellite instability (MSI) is the hallmark of hereditary nonpolyposis colorectal carcinoma (HNPCC) caused by mutations in DNA mismatch-repair genes, mostly hMLH1 and hMSH2. In this study, we evaluated for MSI ACF (n = 16), adenomas (n = 18), carcinomas (n =22), and lymph node metastases (n = 3) from 17 patients with colorectal cancer positive for MSI. Ten patients were members of HNPCC families; 7 patients had no family history of cancer. MSI was found in 7 of 7 (100%) ACF and 11 of 12 (91%) adenomas from patients with HNPCC. MSI was not related to histology and size of ACF. A progressive increase in instability as estimated by the number of shifted bands was observed along the ACF-adenoma-carcinoma sequence. In contrast, two of nine (22%) ACF and none of six adenomas from patients with MSI sporadic carcinoma were unstable at microsatellite loci. hMLH1 or hMSH2 protein expression was altered only in MSI-positive premalignant lesions (ACF and/or adenomas), but not in all MSI-positive lesions in patients with HNPCC. These observations provide evidence of the premalignant nature of ACF in HNPCC and suggest that MSI is a very early event both in HNPCC and in sporadic colorectal carcinogenesis, although in the latter it seems infrequent.

Genomic instability and target gene mutations in colon cancers with different degrees of allelic shifts

Two grades (high and low) of microsatellite instability (MSI) are known, depending on the number of mutated markers and the amount of allelic shifts. Forty-two colorectal tumors, previously found to have high-degree MSI at dinucleotidic repeat loci, were revisited with BAT26, a mononucleotide marker, and the number of shifted bases were counted. Seven tumors, all with local stages at diagnosis, had < or =6-bp deletions and consistently displayed shorter shifts also with other intronic mononucleotide markers. Analysis of mononucleotide tracts in the coding regions of MSH3, MSH6, BAX, and TGFbetaRII in the groups with large (>6 bp) and short (< or =6 bp) allelic shifts showed specific patterns of involvement for the individual genes: TGFbetaRII displayed a uniformly high rate of mutations, while MSH3, MSH6, and BAX were less frequently altered in tumors with short shifts. Our findings suggest that microsatellite instability arises gradually, evenly involving loci with similar features of length and repetition. However, target genes have a specific timing of mutation in this process: TGFbetaRII is involved in the early phases, while BAX and MSH6 are frequently associated with big size shifts and tumors with more advanced stages.

Observations on surgical anatomy for rectal cancer surgery

BACKGROUND/AIMS

The investigators studied the surgical anatomy of the main structures involved in the mobilization of the rectum (Denonvilliers' fascia, mesorectum, middle rectal artery, superior and inferior hypogastric plexuses).

METHODOLOGY

The study was carried out on 20 cadavers (17 unembalmed and 3 embalmed). To study Denonvilliers' fascia, ten embryos and fetuses (11 mm to 80 mm CRL) were also examined.

RESULTS

Denonvilliers' fascia originates from the fusion of the primary pouch of Douglas. The two leaves making up this structure are easily separated. The mesorectum surrounds the rectum on three sides; it is easily separated from the presacral fascia and its connective tissue is bordered by a thin membrane. The middle rectal artery varies in appearance rate, origin, size, distribution and anastomosis. It runs under the lateral ligament and also sends branches to the genital apparatus. Of the two hypogastric plexuses, the inferior is the most difficult one to identify. Its superior branches extend to the rectum, and the inferior ones to the genital apparatus. Because the anterior part contains the parasympathetic nerves and the middle rectal artery, this region is at major risk during surgical dissection.

CONCLUSIONS

A sound understanding of the surgical anatomy of the rectum enables the surgeon to perform a more correct and reasonable procedure in terms of both the extent of surgical treatment and the preservation of important anatomical structures.

Embryologic bases of extended radical resection in pancreatic cancer

OBJECTIVE

To analyze whether an embryologic "rationale" exists to the clinical and anatomicopathological data that suggest the execution of extended resections in patients with pancreatic cancer.

METHODS

Reconstruction of serial histological sections of 18 human embryos and fetuses regarding the pancreatic region; anatomical microdissections of two 9-month fetuses.

RESULTS

The ventral and dorsal pancreatic buds can be identified until the eighth week of development. A close developmental relationship between the dorsal pancreas and the lymphatic and nervous structures in the dorsal mesogastrium is observed. Other lymphatic stations are exclusively related to the ventral pancreas. The posterior fusion of the dorsal mesogastrium is a late event in embryologic development.

CONCLUSIONS

The complete fusion of the 2 pancreatic buds occurs later than previously reported in the literature. The close embryologic relations of these buds with the lymphatic and nervous peripancreatic structures may support the need for extended resections in patients with pancreatic cancer.

Primary adenocarcinoma of the angle of Treitz. Case report and review of the literature

We describe a 54-year-old man who was referred with the diagnosis of adenocarcinoma of the angle of Treitz and treated with the use of a duodenojejunal segmentary resection. After a review of the literature, we emphasize the difficulty of making an early diagnosis and discuss the most appropriate surgical treatment of tumors of the angle of Treitz. The better prognosis of these neoplasms compared with those of the proximal duodenum can be supported by some embryological findings observed from a different research project currently in progress.

[The surgical approach to adrenal incidentaloma]

In this paper the Authors analyse the indications for treatment of adrenal incidentaloma by making a retrospective review of this series. These indications are compared with recent trends which have emerged in the literature.

Postnatal development of intestinal villi in the rat. Determination of villus size gradient

The existence of the so called "Villus Size Gradient" (VSG) which defines the proportional decrease in height of intestinal villi from duodenum to ileum is well documented in adult animals and man. The aim of this study is to define whether the VSG is present since birth or, if not, when and why it appears. We have measured the height of intestinal villi in 25 rats: 5 at 1 day from birth, 5 at 5 days, 5 at 8 days, 5 at 15 days and 5 at 30 days. We have prepared histological slides of a duodenal, jejunal and ileal tract of each animal and measured the height of villi on microphotographs. At day 1 we observed a higher size of duodenal villi statistically significant with respect to jejunum and ileum, while at day 5 no differences were observed between the various intestinal tracts. The VSG become evident 8 days after birth progressively increasing to day 30. The predominance of duodenum present at birth is therefore probably due to the fetal developmental growth which is known to be more precocious in duodenum than in more distal tracts. Five days after birth the intestinal villi are equally developed, while in later ages the VSG appears. So we can conclude that the VSG is a consequence of luminal and humoral factors and not a predetermined event.

Ileo-colon-rectoplasty. An experimental morpho-functional study on the pig

A small bowel loop was interposed, isoperistaltically or pouch-shaped between colon and rectum, (ileo-colon-rectoplasty) in 8 pigs to clarify whether the small intestine can push the semi-solid and septic content of the colon, and whether the function and morphology of the loop are modified with respect to the original. A radiographic and histologic study was performed 6 months after the operation. The structural modifications of the interposed small bowel consist of disappearance of folds, villous atrophy, superficial appearance of the glandular crypts, and, only in the isoperistaltic loop, hypertrophy of the muscular layers. Any modification in the morphologic aspect of the pouch has not been observed, as shown by the radiographic barium enema. Therefore the mucosa of the grafted ileum suffered an architectural change caused from the contact with the fecal material. The lack of structural modifications of the muscular layers and the dimensions of the above colon of the interposed ileal pouch represents an indirect proof of the correct function of reservoir ejection. The experimental results obtained confirm the applicability of this technique in the reconstruction of transit after wide resection of the left colon and rectum, for technical reasons, in man.

Arrangement of the anal striated musculature

A study of the anatomy of the anal striated musculature is performed on 34 adult specimens to reconsider some debated morphologic aspects. The original "eight-shaped" arrangement of the fibers of the pubococcygeus is pointed out, suggesting a definite role of the muscle as a superior part of the continence muscular complex; the intermediate part seems to be formed by the puborectalis loop and the deep external anal sphincter, not always separable. Finally, the inferior portion is represented by the superficial sphincter, which shows anatomic behavior similar to that of the pubococcygeus.

Myoelectric activity of an ileal isoperistaltic or antiperistaltic loop interposed between colon and rectum: an experimental study in pigs

The myoelectric activity of 25-30 cm ileal loops interposed isoperistaltically or antiperistaltically between colon and rectum was investigated 1-3 and 20-22 weeks after surgery, in growing pigs chronically fitted with intraparietal electrodes on the loop and the ileum. The fundamental motor profile of the small intestine consisting of migrating myoelectric complexes (MMC) was present on both loops; the MMCs were propagated on the antiperistaltic loop in the original anatomical direction. There was no coordination between the occurrence of phase 3 on the loop and the ileum. Some minor differences concerning the duration, the frequency and the velocity of propagation of phase 3 were observed between the loops and the ileum. Moreover propagated clusters of spike bursts and propagated long duration spike bursts appeared on the isoperistaltic and antiperistaltic loop, respectively, but not on the ileum. No prominent differences in the motor profiles of the loops have been observed between 1-3 and 20-22 weeks after surgery. It is concluded that despite the presence of semisolid contents with an abundant microflora the fundamental intestinal motor profile persists in ileal loops interposed between colon and rectum.

Questions about the uncertain presence of muscle spindles in the human external anal sphincter

The verification of the uncertain presence of muscle spindles in the external anal sphincter is important in the comprehension of the pathophysiology of continence. The authors failed to demonstrate these proprioceptive structures in 10 human sphincters examined with different histological techniques, whereas they found some typical muscle spindles in the puborectalis muscles. The possible interpretations of the different results on the subject in the literature together with their functional implications are discussed.

Modifications of the trophism of intestinal mucosa after intestinal and bilio-pancreatic diversion in the rat

Morphofunctional alterations to the intestinal mucosa are influenced by three main factors: food, bilio-pancreatic secretions, intestinal hormones. In order to assess the importance of each one, histological and histochemical tests were performed on different segments of intestine taken from rats which were sacrificed one month after the following procedure: gastrojejunal anastomosis on a Roux loop (Model I); same procedure plus biliopancreatic bypass into the jejunum (Model II). When compared to the controls, Model I duodenum samples revealed hypertrophy of the entire wall with "bundles" of villi, while Model II samples showed a clear hypotrophy and reduction in the number of duodenal villi. To such modifications of the duodenum correspond longer, thinner villi in the other bowel segments, particularly in the jejunum and distal ileum. These results suggest that the predominant trophic effect derives from contact with biliopancreatic secretions at a proximal level. The modifications of the duodenal mucosa appear to regulate the trophism of the distal segments probably by the secretion of distant acting enterohormones.

Development of the anal canal muscles

The anal canal muscles development is studied in 18 human embryos. The external anal sphincter results to origin common with the urogenital sphincter from the cloacal sphincter. The muscle, after its appearance, is subdivided into two portions from a thin mesenchymal layer. Moreover, our embryologic study clearly confirms that the puborectalis muscle is a portion of the levator ani, its primordium being common with the ileo and the pubococcygeus muscles. The anal smooth musculature appears later than the striated one.

[Suspensory elements of the anal canal. Anatomo-surgical considerations]

Continence depends not only on correct muscular function but also on the integrity of the suspensory structures of the anal canal, the latter being the subject of this study performed on embryological and adult specimens. The role of the perineal body as an insertion tendon common to all the striated muscles (pubo-coc-cygeus, superficial striated sphincter) which anchor the anal canal to the surrounding structures is pointed out. The characteristic behaviour of the longitudinal muscle that links the striated musculature to the visceral cylinder is also described.