Must early postoperative oral intake be limited to laparoscopy?

PURPOSE

This prospective, randomized study was designed to evaluate whether or not early postoperative feeding (claimed as a unique benefit of laparoscopic surgery) is possible after laparotomy and colorectal resection.

METHODS

The trial was performed between July 1, 1992 and October 31, 1992 and included all 64 consecutive patients who underwent laparotomy with either a colonic or an ileal resection. In all cases the nasogastric tube was removed immediately after the operation. Group 1 consisted of 32 patients (age range, 15-81 years; mean, 52 years) who received a regular diet on the first postoperative morning. Group 2 consisted of 32 patients (age range, 15-87 years; mean, 52 years) who were fed in a traditional manner. Regular food was permitted after resolution of ileus as defined by resumption of bowel movements in the absence of abdominal distention, nausea, or vomiting.

RESULTS

The rate of nasogastric tube reinsertion for distention with persistent vomiting was 18.7 percent (six patients) in Group 1 and 12.5 percent (four patients) in Group 2. Although vomiting was experienced more frequently by patients in Group 1 (44 percent vs. 25 percent, respectively), there was no difference between the two groups with regard to the duration of postoperative ileus (3.6 vs. 3.4 days, respectively). In the 26 patients from Group 1 who did not require nasogastric tube reinsertion, there was a trend toward shorter hospitalization (6.7 vs. 8.0 days, respectively).

CONCLUSION

Early oral intake is possible after laparotomy and colorectal resection. Thus, the laparoscopic surgeon's claim of early tolerated oral intake may not be unique to laparoscopy.

wingless acts through the shaggy/zeste-white 3 kinase to direct dorsal-ventral axis formation in the Drosophila leg

The secreted glycoproteins encoded by Wnt genes are thought to function as intercellular signaling molecules which convey positional information. Localized expression of Wingless protein is required to specify the fate of ventral cells in the developing Drosophila leg. We report here that Wingless acts through inactivation of the shaggy/zeste white 3 protein kinase to specify ventral cell fate in the leg. Ectopic expression of Wingless outside its normal ventral domain has been shown reorganize the dorsal-ventral axis of the leg in a non-autonomous manner. Using genetic mosaics, we show that cells that lack shaggy/zeste white 3 activity can influence the fate of neighboring cells to reorganize dorsal-ventral pattern in the leg, in the same manner as Wingless-expressing cells. Therefore, clones of cells that lack shaggy/zeste white 3 activity exhibit all of the organizer activity previously attributed to Wingless-expressing cells, but do so without expressing wingless. We also show that the organizing activity of ventral cells depends upon the location of the clone along the dorsal-ventral axis. These findings suggest that Wingless protein does not function as a morphogen in the dorsal-ventral axis of the leg.

Mutations and expression of the p53 gene in rat bladder carcinomas and cell lines

Abnormalities of the p53 gene are frequently observed in human tumors, including urinary bladder carcinoma, suggesting that p53 plays an important role in human carcinogenesis. However, its role in rat bladder carcinogenesis is unclear. We investigated p53 gene mutations and expression in rat urinary bladder carcinogenesis in vivo and in vitro. Fifteen urothelial cell lines, including six untransformed (nontumorigenic) ones, six transformed (tumorigenic) in vitro, and three derived from tumors induced in vivo, were examined for p53 expression by immunochemical analysis and for p53 mutations; in addition, 81 rat bladders were analyzed immunohistochemically for p53 expression, and 23 rat bladder tumors were analyzed for p53 mutations. Four cell lines had mutations in the p53 gene. Two of these were missense point mutations, and the other two were splicing mutations. On the other hand, no mutations were found in the bladder tumors induced in rats. By immunoprecipitation with PAb240, which is supposed to be specific for mutant p53, we detected mutations in three of the cell lines; PAb240 did not react with wild-type p53. However, in all cell lines and in growing populations of primary cultured bladder urothelial cells, p53 expression was detected immunohistochemically or by western blotting using PAb240 or PAb 421 monoclonal antibodies. In a high percentage of transitional cell carcinomas, wild-type p53 expression was detected by immunohistochemical analysis with PAb240. These results suggest that p53 gene mutations may not occur frequently in rat bladder carcinogenesis in vivo but may occur in vitro and that p53 overexpression detected immunohistochemically is common and may be related to cell proliferation rather than to the presence of mutations in rat bladder carcinogenesis.

A comparison of the effects of sodium saccharin in NBR rats and in intact and castrated male F344 rats

High doses of sodium saccharin (NaSac) increase proliferation in the bladder of the rat, with a male preponderance. The possibility that alpha 2u-globulin is involved in its mechanism of action was evaluated by feeding it at 7.5% of the diet to NCI-Black-Reiter (NBR) male rats, which do not synthesize liver-derived alpha 2u-globulin. NaSac affected urinary parameters similarly in F344 and NBR male rats, but NBR rats consumed more water leading to greater urinary volume. NaSac produced less proliferation in NBR than in intact F344 rats, with intermediate changes in castrated F344 males, which had intermediate urinary alpha 2u-globulin levels.

Simple technique for pelvic drain placement in laparoscopic abdominoperineal resection

The placement of a pelvic drain after abdominoperineal resection of the rectum is a routine practice. We present a simple technique for laparoscopic placement of such a drain through the abdominal wall following laparoscopic abdominoperineal resection.

p53 mutation is infrequent and might not give a growth advantage in rat bladder carcinogenesis in vivo

Abnormalities of the p53 gene are frequently observed in human tumors, including urinary bladder carcinoma, suggesting that p53 plays an important role in human carcinogenesis. However, its role in rat bladder carcinogenesis is unclear. In this study, we investigated the presence of p53 mutations in 122 urinary bladder tumors induced in F344 rats in the following carcinogenesis models: (i) 0.2% N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT; 6 weeks) in the diet followed by 3% or 5% sodium saccharin in the diet, 5% sodium ascorbate, 3.12% calcium saccharin (CaSac), 1.34% sodium chloride (NaCl), 5.2% CaSac plus 1.34% NaCl, or basal diet alone (72 weeks); and (ii) 0.2% FANFT, 0.05% N-(4-hydroxybutyl)nitrosamine in the drinking water, N-methyl-N-nitrosourea 20 mg/kg body wt, i.p. twice per week, or basal diet alone (4 weeks), followed by 3% uracil in the diet (20 weeks). Polymerase chain reaction-single-strand conformation polymorphism analysis and direct sequencing were performed for exons 5-8 in the rat p53 gene. We found nine tumors (7.4%) with p53 mutations. Two tumors had two mutations in the p53 gene. The tumors that had p53 mutations were relatively smaller than those that did not have p53 mutations. There were no mutation clusters among the treatments or hot-spots for p53 mutations. These results indicate that p53 mutation is infrequent in bladder carcinogenesis in rats, and when it does occur, it does not appear to provide a growth advantage.

An initial comparative study of two techniques of laparoscopic colonic anastomosis and mesenteric defect closure

Laparoscopic colon and rectal surgery is still in its nascent stages of development. The ease, efficacy, and safety of intracorporeal mechanical colonic anastomosis are contingent upon expensive stapling devices. Although mobilization and mesenteric division are feasible, a method of inexpensive rapid anastomosis is not. A single inexpensive multifire stapler which could be used both to fashion the anastomosis and to close the mesenteric defect would be ideal. Therefore, this prospective randomized study was undertaken to compare the clinical and functional results of laparoscopic colotomy closure performed using the Endopath EMS hernia stapler (EMS; Ethicon Endosurgery Inc., Cincinnati, OH) to results of using standard two-layer hand suturing (HS). Both the colotomy itself and the mesenteric defect closure sites were included in the randomization and analysis. The abdominal cavity was assessed for evidence of anastomotic leakage, abscess, and adhesion formation. In addition, radiographic luminal diameter, bursting strength, and histology were evaluated. Eight healthy pigs were randomized to either the EMS (N = 4) or HS (N = 4). There was no evidence of leakage, abscesses, or adhesion formation in either group; however, the mesenteric defect revealed more scarring in the HS than in the EMS animals. There were no significant differences in either luminal diameter (HS: mean = 0.92 cm; EMS: mean = 0.91 cm) or bursting strength (HS: mean = 171 mm Hg; EMS: mean = 157 mm Hg) (P > 0.05). Histologic analysis also demonstrated no difference in inflammation, necrosis, or fibrosis. This study suggests that this technique can be safely applied to both colotomy closure and mesenteric defect repair.(ABSTRACT TRUNCATED AT 250 WORDS)

The diagnosis of anal ulcers in AIDS patients

Recent reports have suggested that routine microscopic evaluation of anal ulcer tissue from AIDS patients is not the most accurate way to diagnose viral infection. This study was undertaken to determine if either viral culture (VC) or immunohistochemistry (IHC) can improve the diagnostic accuracy as compared with routine hematoxylin and eosin (H&E) staining. Specifically, we sought to identify inclusion bodies of cytomegalovirus (CMV) or herpes simplex virus (HSV) to assist in the diagnosis of CMV or HSV. All patients had clinical evidence of an anal ulcer or a nonhealing anal fissure. Duration of symptoms ranged from 1 week to 3 months with a mean of 6 weeks. All specimens were submitted for viral culture in addition to routine H&E staining; immunohistochemistry was also performed. Twenty-five paraffin-embedded anal ulcer biopsies from 23 male patients (age range 27-73; mean 37.4 years) with the diagnosis of AIDS or AIDS-related complex (ARC) were reviewed over a 4 year period (1988-1992). Routine H&E staining revealed 6 (22%) specimens with CMV inclusions. Four of these 6 reacted positively with IHC (67%) and one was positive on viral culture (17%). In the remaining 19 specimens that did not reveal infection with CMV (78%), IHC was positive in 2 patients (10%) and viral culture was positive in 1 patient (5%). Although HSV was not seen in any of the specimens on H&E staining, IHC was positive in one patient (3.5%) and viral culture reacted positively in 8 (29%) specimens. Thus IHC is a good confirmatory test for CMV inclusions and can be used to achieve a definitive diagnosis in equivocal cases.(ABSTRACT TRUNCATED AT 250 WORDS)

A Drosophila homologue of human Sp1 is a head-specific segmentation gene

Segmentation in Drosophila is based on a cascade of hierarchical gene interactions initiated by maternally deposited morphogens that define the spatially restricted domains of gap gene expression at blastoderm (reviewed in ref. 1). Although segmentation of the embryonic head is morphologically obscured, the repeated patterns of expression of the segment polarity genes reflect the formation of seven head segments; two of these depend on the segmentation and homeotic genes used in the trunk, whereas the others form as a result of the activity of the head-specific genes orthodenticle (otd), empty spiracles (ems) and buttonhead (btd). The genes ems and otd encode homeodomain proteins, suggesting that they may function as transcription factors. They are expressed in overlapping stripes in the early embryonic head of Drosophila, and their vertebrate homologues, otx and emx, are expressed in overlapping domains in the anterior central nervous system of the mouse embryo. We show here that btd is expressed in a stripe covering the head analgen of the segments affected in btd lack-of-function mutants and that btd encodes a zinc-finger-type transcription factor with sequence and functional similarity to the prototype mammalian transcription factor Sp1 (ref. 9). When expressed in the spatial pattern of btd, a transgene providing Sp1 activity can support development of the mandibular segment in the head of btd mutant embryos. A ubiquitous transcription factor from humans can therefore replace an essential component of the genetic circuitry required to specify the development of a particular head segment in the fly.

Use of cell proliferation data in modeling urinary bladder carcinogenesis

A multistage, probabilistic, biologically based model of carcinogenesis has been developed involving qualitative and quantitative aspects of the process. A chemical can affect the risk of cancer by directly damaging DNA and/or increasing the number of cell divisions during which errors in DNA replication can occur. Based on this model, carcinogens are classified as genotoxic versus nongenotoxic; nongenotoxic chemicals are further divided on the basis of whether or not they act through a specific cell receptor. Nongenotoxic compounds, particularly those acting through a nonreceptor mechanism, are likely to have dose and/or species-specific thresholds. This classification also implies the existence of chemicals that will be carcinogenic at high doses in animal models, but because of dose and/or mechanistic considerations, will not be carcinogenic to humans at levels of exposure. N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide (FANFT) and 2-acetylaminofluorene (AAF) are classical genotoxic bladder carcinogens that also cause proliferative effects at higher doses. Although there is an apparent no-effect level for the urinary bladder carcinogenicity of these two compounds at low doses, in reality, DNA adducts form at these low levels, and it is likely that there is a cancer effect (no threshold), but it is below the level of detection of the bioassay. These conclusions are based on studies involving multiple doses and time points in rodents, including results from the ED01. Pellets implanted directly into the rodent bladder lumen or calculi formed in the urine as a result of an administered chemical cause abrasion of the urothelium, and a marked increase in cell proliferation and cell number, and ultimately tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Laparoscopic colorectal surgery: a prospective assessment and current perspective

Between August 1991 and June 1993, 74 laparoscopic and laparoscopically assisted colonic and rectal operations were performed. A variety of procedures were carried out including 32 total abdominal colectomies (group 1), 32 segmental resections (group 2) and ten constructions of a diverting stoma without formal resection (group 3). Indications for surgery were mucosal ulcerative colitis in 20 patients, carcinoma in 12, polyposis in six, Crohn's disease in seven and other conditions in the remaining 29. The 74 comprised 42 male and 32 female patients of mean age 45 (range 12-88) years. The median (range) duration of the procedure was 3.0 (1.0-6.5) h for the entire group, 3.9 (2.5-6.5) h for group 1, 2.9 (1.5-5.5) h for group 2 and 1.8 (1.0-2.5) h for group 3. The median (range) length of ileus was 3.0 (2-7) days overall; respective times for groups 1-3 were 3.5 (2-7), 3.0 (2-7) and 2.0 (1-4) days. The median (range) length of hospitalization was 7.0 (2-40) days, 8.1 (4-19) days in group 1, 7.0 (4-20) days in group 2 and 6.0 (2-40) days in group 3. Ten patients (14 per cent) developed intraoperative and 15 (20 per cent) postoperative complications; there were no deaths. These results failed to confirm any significant advantages of laparoscopic or laparoscopically assisted colorectal surgery. Specifically, neither the operating time, nor length of ileus, nor length of hospitalization was improved over standard procedures. Advances in technology and surgical technique may improve such findings in the future.

Interaction between dorsal and ventral cells in the imaginal disc directs wing development in Drosophila

The adult appendages of Drosophila develop from imaginal discs. An early step in disc patterning involves the formation of developmental boundaries that subdivide the discs into compartments. Anterior and posterior compartments are established in the embryo. Later in development a new boundary originates to subdivide the wing disc into dorsal and ventral compartments, which correspond to the dorsal and ventral surfaces of the adult wing. We report here that spatially localized expression of the homeobox gene apterous (ap) specifies the identity of dorsal cells in the wing. The boundary of cell lineage restriction between dorsal and ventral compartments coincides with the limit of the domain of ap expression. Using genetic mosaics, we show that juxtaposition of dorsal and ventral cells induces formation of the wing margin. We present evidence that the dorsal-ventral boundary promotes growth and serves as a pattern-organizing center in the wing disc.

Effects of dietary iron and folate supplementation on the physiological changes produced in weanling rats by sodium saccharin exposure

Exposure of rats to high dietary levels of sodium saccharin (NaSac) started in utero produce physiological effects at 30 days post-birth that are similar to those found in pups of iron-deficient dams. These similarities suggest that some of the changes due to NaSac are secondary to iron deficiency. The present experiment investigated whether the effects of 7.5% dietary NaSac in the newborn rat could be prevented by dietary iron and/or folate supplementation. The NaSac-related effects prevented by iron supplementation included anaemia, decreased serum iron and folate, increased serum cholesterol and triglyceride and increased serum vitamin E. Folate supplementation prevented NaSac-induced depression of serum folate and increase in serum vitamin E. Although bladder hyperplasia was increased by dietary iron and/or folate supplementation, the majority of the urinary chemistry changes associated with NaSac treatment were not affected. The results show that some physiological changes associated with NaSac treatment in the newborn rat may occur as a consequence of iron deficiency rather than a direct effect of NaSac treatment. These changes may be independent of the urinary and bladder effects, which are not reversed by iron supplementation.

Dissection of an indirect autoregulatory response of a homeotic Drosophila gene

Homeotic genes often use autoregulation as a mechanism to maintain their expression. Autoregulation of Ultrabithorax (Ubx) in the visceral mesoderm is at least partly indirect and mediated by extracellular signalling from wingless (wg) and decapentaplegic (dpp). Ubx controls the localized expression of these two extracellular proteins. Here, we identify separate wg and dpp response elements within upstream sequences of Ubx. Our evidence suggests that there are two distinct response factors each of which, after signal-induced activation, mediates transcriptional activation through its cognate element, whereas each element is recognized by a repressor in the absence of the corresponding signal. We show that the response factors and other components for transmission of the wg and, probably, of the dpp signal are present throughout the midgut mesoderm. Thus, there may be ubiquitous repression, preventing Ubx autoregulation throughout the visceral mesoderm, which is relieved locally by wg and dpp signalling. Evidently, the two signals convey positional information, allowing visceral mesoderm cells to reassess their position at advanced stages of embryogenesis and to decide whether or not to maintain expression of a homeotic gene.

Application of scanning electron microscopy and X-ray analysis to urinary tract cancer in animals and humans

Scanning electron microscopy (SEM) has proven useful in various aspects of urinary bladder carcinogenesis research and these are reviewed as they pertain to our research involving sodium saccharin in the rat. Sodium saccharin-carcinogenesis in rats requires administration at high doses beginning at birth or earlier. Administration beginning at ages of 5 weeks or later results in much lower incidences of bladder tumors. Methods were developed for examining the rat fetal and neonatal bladder to further evaluate effects at these critical ages. Several significant differences were found by SEM between the fetal bladder compared to the adult. The typical polygonal superficial cells of the bladder with asymmetric unit membrane were present before birth, but the slow turnover rate of the adult bladder did not occur until 3-4 weeks of age. Sodium saccharin causes increased proliferation rates and hyperplasia of the urothelium which is dose-dependent. SEM was found to be more sensitive than either light microscopy or labeling indices to detect the earliest lesions induced by sodium saccharin. More recently, amorphous and crystalline material in the urine of rats fed high doses of sodium saccharin were detected by SEM examinations which contained silicon as well as calcium, phosphate, and magnesium as detected by energy dispersive X-ray analysis (EDS) with the SEM. These parameters may be relevant to differences between rats and humans and pertain to extrapolations regarding risk assessment.

Distal-less is a downstream gene of Deformed required for ventral maxillary identity

The homeotic selector (HOM) proteins are required for the diversification of the anterior-posterior axis of the Drosophila body plan, assigning unique identities to regional domains of cells comprising one or a few parasegments or segments. The HOM proteins apparently accomplish this task by the transcriptional regulation of numerous downstream genes. At present few downstream genes are known, so models of how downstream genes mediate HOM functions are based more on intuition than information. Our results indicate that Distal-less is a downstream gene of the HOM gene Deformed, and Distal-less function is required for the elaboration of a subset of the maxillary epidermal identities specified by Deformed. The regulatory effect of Deformed on Distal-less is mediated by a ventral maxillary-specific enhancer located 3′ of the Distal-less transcription unit. We propose that Deformed and Distal-less, both of which encode homeodomain transcription factors that are persistently expressed in ventral maxillary cells, combinatorially specify a subsegmental code required for a group of cells to differentiate maxillary cirri.

Allocation of the thoracic imaginal primordia in the Drosophila embryo

The primordia of the thoracic imaginal discs of the Drosophila embryo originate as groups of cells spanning the parasegment boundary. We present evidence that the thoracic imaginal primordia are allocated in response to signals from the wingless (wg) and decapentaplegic (dpp) gene products. Rows of cells that express wg intersect rows of cells that express dpp to form a ladder-like pattern in the ectoderm of the germ band extended embryo. The imaginal primordia originate as groups of cells which lie near these intersection points. We have used a molecular probe derived from the Distal-less (Dll) gene to show that this population contains progenitor cells for both the dorsal (i.e. wing) and ventral (i.e. leg) discs. Although we show that Dll function is not required for allocation of imaginal cells, activation of an early Dll enhancer may serve as a molecular marker for allocation. A group of cells, which includes the imaginal progenitors, activate this enhancer in response to intercellular signals from wg and perhaps from dpp. We have used a conditional allele of wg to show that wg function is transiently required for both allocation of the imaginal primordia and for initiation of Dll expression in these cells during the brief interval when wg and dpp form the ladder-like pattern. Allocation of the imaginal primordium and activation of Dll expression appear to be parallel responses to a single set of positional cues.

Proconvulsant and anticonvulsant properties of ethanol: studies of electrographic seizures in vitro

Recent studies have demonstrated that ethanol is a potent blocker of N-methyl-D-aspartate (NMDA) receptor mediated responses. It is well known that neuroplasticity processes depend on the activation of the NMDA type of excitatory amino acid receptor. We have used an in vitro model of electrographic seizures (EGS), a neuroplasticity process, to examine the effect of varying ethanol concentrations. In the present experiment, slices of rat hippocampus were electrically stimulated to produce stimulus train-induced epileptiform bursting in area CA3. EGS duration and intensity was enhanced by 10 mM ethanol, whereas increasing the concentration of ethanol (60-300 mM) attenuated established EGSs. Ethanol also raised the threshold to elicit an EGS. Removal of low ethanol concentrations resulted in a hyperexcitable state, with increased EGS duration and intensity. These results reflect acute biphasic effects of ethanol across concentrations, and withdrawal hyperexcitability. The effects of ethanol on EGSs, at concentrations which elicit intoxication but not anesthesia (< 75 mM), resemble the actions produced by NMDA antagonists on EGSs. Therefore the effects of ethanol on stimulus train-induced EGSs may be mediated through an action at the NMDA receptor complex.

Laparoscopic colorectal resection for cancer: the Cleveland Clinic Florida experience

Since the first successful laparoscopic cholecystectomy was performed in 1987, surgeons have begun to focus their attention on more diverse procedures. The last few years have brought a tremendous amount of enthusiasm toward laparoscopic surgery, which has finally reached the colorectal surgical communities. Currently, laparoscopic bowel surgery is undergoing critical appraisal. Through meaningful prospective data retrieval, answers are being obtained to questions dealing with the efficacy and utility of this technique for colorectal diseases. Specifically, although laparoscopic colorectal surgery is feasible, one cannot definitively attest to its superiority or even equivalence to standard open laparotomy. Furthermore, it will take 5 years before we begin to collect data regarding survival rates and local recurrence for the patient with colorectal carcinoma. This article discusses the technique utilized, and our own experience with laparoscopic colorectal surgery for malignancy.

Sequencing analysis of Ha-, Ki-, and N-ras genes in rat urinary bladder tumors induced by N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) and sodium saccharin

Male F344 rats were fed N[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) for up to 4 wk, then given the basal diet with or without 5% sodium saccharin for up to 100 wk. In a previous study, we demonstrated point mutations in codons 12 and 61 of Ha-ras gene among eleven transitional cell carcinomas (TCC), one undifferentiated carcinoma, and two sarcomas of the urinary bladder (Mol Carcinogen 3:210-215, 1990). In this study, Ha-ras, Ki-ras, and N-ras sequences were examined by polymerase chain reaction (PCR) and direct DNA sequencing. The results confirm the point mutation in codon 61 (CAA to CGA in 5 TCCs and to CTA in one TCC) of the Ha-ras gene. Mutation at codon 12 was not confirmed. No mutation was found in the Ki-ras gene. Sequences of the N-ras gene exons 1 and 2 were determined, and no mutations was detected. These results suggest the involvement of activated Ha-ras gene, but not Ki-N or N-ras gene, in rat urinary bladder carcinogenesis induced by FANFT. Subsequent sodium saccharin administration did not affect the changes in Ha-ras gene.

Intraocular fluid cultures after primary pars plana vitrectomy

To determine what organisms enter the eye and remain in the eye after pars plana vitrectomy, vitreous cavity aspirates were cultured postoperatively. Two of 33 (6%) consecutive eyes undergoing primary pars plana vitrectomy had positive cultures. One sample grew a single colony of Staphylococcus epidermidis, the second grew two colonies of Acinetobacter lwoffi. Neither of these eyes developed endophthalmitis. This study demonstrates that bacteria enter the eye at a low rate during pars plana vitrectomy and that the eye on which a vitrectomy has been performed is capable of clearing a low inoculum of bacteria.