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Can Irregular Z Line Be Reversed

author
Paul Gonzalez
• Monday, 02 November, 2020
• 23 min read

When I type that into google, all the results scream “BARRETT'S ESOPHAGUS” like I'm about to die from cancer. “ “My biopsy didn't reveal anything even close to Barrett's esophagus (apparently).

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(Source: accessmedicine.mhmedical.com)

Contents

The Line demarcates the squamocolumnar junction (SCJ), the transition from the squamous esophageal mucosa to the columnar mucosa lining the stomach, or in cases of Barrett’s esophagus, between the squamous and internalized columnar epithelium of the meta plastic segment. An irregularZline is characterized by < 1 cm columnar tongues that extend proximal to the gastroesophageal junction, a finding that has been reported in approximately 10–15% of the population undergoing upper endoscopy .

Nevertheless, the clinical significance of this finding with respect to the risk of progression to neoplasm in patients with an irregularZline and IM is unclear . While prior guidelines are in conflict with regard to the management strategies for putative Barrett’s esophagus (BE) segments < 1 cm, the most recent American College of Gastroenterology (ACG) guidelines recommend against obtaining biopsies from an irregularZline, a recommendation made due to the poor endoscopic standardization of this finding (one endoscopic’s normal Line is another’s irregularZline), the additional costs associated with this practice, the potential for patient anxiety, and the low rates of prevalent and incident dysplasia and esophageal adenocarcinoma (EAC) found in these lesions.

Also, patients with an irregularZline who harbor IM might be enrolled in endoscopic surveillance protocols, necessitating the costs and inconvenience of recurrent surveillance endoscopy, as well as the stigma of a disease label for a potentially neoplastic condition. A prospective single-center study by Moskovitz et al. published in the current issue of Digestive Diseases and Sciences describes the risk of developing BE, dysplasia, and EAC in those with an irregularZline and IM compared to those with an irregularZline without I'm.

There were 166 patients endoscopically diagnosed with an irregularZline, defined here as variability of 5 mm of the squamocolumnar junction on index endoscopy. Of the 166 patients who underwent upper endoscopy for indications such as heartburn, dysphagia, and chest pain, 39% (n = 64) had biopsy-proven I'm.

The authors note in their conclusion that patients with an irregularZline “do not develop major BE complication in more than 5 years of follow-up.” Yet, they also suggest in their discussion that, due to the 16% incidence of BE in the IM-positive group and the two patients who developed LED, “longer follow-up studies may reveal a more malicious nature of irregularZline with intestinal metaplasia.” This study has several commendable strengths: It is prospective, with a standardized biopsy protocol with follow-up, at a median of 70 months, which is of sufficient length to enable the observation of clinically significant trends, and appropriate covariance were considered, including careful assessment of the Line.

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Several shortcomings are also evident: Loss to follow-up was substantial, especially in the group with no IM, where almost half of patients did not have a repeat examination; also, given that an irregularZline is not an indication for a repeat EGD, it is unclear whether these follow-up examinations were being done as part of the study protocol, or for clinical care. If the latter is true, the results must be viewed in a somewhat different light, due to the bias inherent in the motivations influencing patients to have repeat procedures: Patients who return for ongoing HERD symptoms might be expected to have a different prevalence of BE than those who are asymptomatic.

The results of the present study add to a sparse, confusing, and inconclusive literature on the natural history of the irregularZline (Table 1). Theta et al. performed a recent prospective multi center study of 167 patients with an irregularZline and I'm.

The presence of a hiatal hernia can not only make it more difficult to accurately differentiate between an irregularZline and short-segment BE on index endoscopic exam, but can also falsely increase the reported prevalence of I'm if biopsies were obtained from the cardiac due to sampling error. These results are similar to a previous study that reported that more than half of those with an irregularZline with I'm on index biopsy did not have I'm on follow-up examination , underscoring the problem of sampling error that is magnified in the presence of very short segments of columnar mucosa.

Even with all this confusion and potential for bias, the results from this study and the existing literature in balance show that the irregularZline is a low-risk lesion. While a four-grade classification system for assessing the Line has been previously proposed that correlated with prevalence of I'm , it has not been adopted and applied in the clinical setting.

Until such time when superior measurements of minute changes around the Line are possible or novel biomarkers are validated, endoscopies should recognize that small amounts of Barrett’s, like beauty, are in the eye of the beholder. Theta IN, Vennalaganti P, Vennelaganti S, et al. Low risk of high-grade dysplasia or esophageal adenocarcinoma among patients with Barrett’s esophagus less than 1 cm (irregular Z line) within 5 years of index endoscopy.

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(Source: abdominalkey.com)

Hickman R, Levi Z, Villain A, Avid I, NIV Y. Predictors of specialized intestinal metaplasia in patients with an incidental irregular Z line. Significance of intestinal metaplasia in different areas of esophagus including esophagogastric junction.

Shaheen NJ, Fall GW, Dyer PG, Gerson LB. Moskovitz D, Levi Z, Bolton D, et al. Risk of neoplastic progression among patients with an irregular Z line on long-term follow-up.

Epidemiology and natural history of intestinal metaplasia of the gastroesophageal junction and Barrett’s esophagus: a population-based study. Length of Barrett’esophagus and cancer risk: implications from a large sample of patients with early esophageal adenocarcinoma.

Symptoms of Barrett's esophagus are similar to those of HERD and include heartburn, chronic cough, laryngitis and nausea. Both an ultrasound and a biopsy of tissue are required for a diagnosis of Barrett's esophagus.

Tucamogi Posted 3/1/2011 10:01 PM (GMT -7) But I have been ill for several months, acid reflux and indigestion after even small meals.

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(Source: www.youtube.com)

The doc mentioned an irregularzline and biopsied for poss Barrett. There was also some erythematous (spell) mucosa in the lower colon.

I suggest your start a new thread on the main page, so people can more easily see post and respond to it! Glad you've joined us! Denise MTL) couplers, shown right, come with all Micro-Trains locomotives and rolling stock (and, until recently, engines and cars from many other Z -scale manufacturers).

Then, in 2008, something funny happened: Micro-Trains stopped allowing other manufacturers to sell rolling stock and locomotives with Micro-Trains couplers and trucks. This, of course, was bad news for these smaller brands, who now had to choose between shipping their products without couplers and wheels, or (quickly) developing their own.

So, develop their own is what they did: both American Z Lines and Uncle Will's Full Throttle introduced their own proprietary couplers and trucks. This kept their rolling stock moving, but also ended up adding further confusion and frustration to a market where two standards were already too many.

Marlin fishhook couplers are larger, and therefore more sturdy and forgiving than their MTL counterparts. Marlin uses these couplers on most of their rolling stock (some exceptions listed later in this article), and has done so since the dawn of Z scale in 1972.

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As a result, the fishhook is the standard Z -scale coupler, particularly among European models from Marlin and many other manufacturers. They're also quite fragile; the plastic parts can break, the spring can become deformed (or lost), and the whole mechanism can jam.

Plus, it eliminates the slinky effect exhibited when starting or stopping long trains with MTL couplers (which, admittedly, has never really bothered me). But my biggest beef is that the early ALL couplers are lousy at staying coupled; my F59PH California Corridor set couldn't make it once around my track without dropping at least one car until I swapped out the ALL couplers for MTL #905s.

ALL Auto-Latch couplers are much better at staying coupled then their predecessors, and the whole mechanism appears to be much stronger than MTL's knuckle. They also couple with their own more easily, and even mate nicely with MTL knuckle couplers.

As a bonus, the metal wheels on all of ALL's trucks are so superior to MTL's featherweight plastic wheel sets it's not even funny. Second, Auto-Latch shanks are longer than those on MTL units, creating a broader space between coupled cars (sorry, fans of close-coupling).

These couplers have been known to fall off fairly easily; ALL recommends gluing them to solve this problem. From reports, it appears that Bowler Bucklers offer a knuckle design, metal wheels (hooray), and integrated plastic springs (akin to ALL couplers).

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Avoid them if at all possible, although they remain the only practical way to install Marklin-compatible couplers on MTL, ALL, and Full-Throttle locomotives and rolling stock. Although they're no longer available preinstalled on Micro-Trains rolling stock, you can still get these couplers by themselves (#907 and #908) or on trucks (look for a “-M” after the model number; e.g., 995 80 213-M).

The ingenious photo-etched coupler on this stunning powered KOF II by Z -Modellbau was designed by Dr. Andreas Scheme to mate with Marlin rolling stock. It does away with the bulky coupler box used on Marlin units (for which there is obviously no space here), yet works remarkably well.

It comes pre-installed on Marlin's F7 A-B-A sets, which must be permanently coupled to accompany the wires that span between the two powered units. This variation of the Marlin draw bar, previous, snaps off for easy removal.

For instance, it connects the tender of the Marlin's 81360 steam-powered rotary snowplow with the front of the included 2-10-0 Class 50 locomotive. Used on their TEE, ICE, and other multi-unit sets, Marlin developed proprietary couplers to not only close-couple the powered locomotives and cars but to transmit electricity between them.

Then bend it back into shape and use a soldering iron to re-weld the pins and fasten the pieces together. There have reportedly been problems with this coupler, included difficulty in coupling as well as unintended uncoupling.

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(Source: www.youtube.com)

Standard N-scale Rapid couplers support remote uncoupling by use of plastic trip pins underneath (akin to Marlin's fishhooks), but since these pins appear absent on Pro- Z's offerings, I don't expect they support this feature. I don't yet have personal experience with these couplers in Z -scale, although I always found N-scale Rapids to be hideous, and their square shape makes coupling on a curve difficult.

Hamilton's excellent Japanese PJ Gauge page shows that they can be converted to MTL knuckle couplers. What appears to be another MTL-compatible knuckle coupler, these come on Asia's Real locomotives and rolling stock.

Hamilton's excellent Japanese PJ Gauge page shows that they can be converted to MTL knuckle couplers. They offer no automatic coupling or uncoupling, and don't stay together particularly well unless your track is perfectly level and uniform.

They're even (scarcely) available separately as Railed # 9150, should you desire to convert any of your other rolling stock. This beast was used on some of those early units (in particular, the dummy F7 chassis) to mate with Marlin fishhook couplers, and attaches to the truck pivot point; note the integrated plastic centering spring.

For instance, the three-axle truck on the tender in the photo (of the West model Hudson F6) connects quite nicely to Marlin rolling stock, even if it doesn't look all that great. Even Marlin uses a simple pin as a front coupler on some of their 2-6-0 steam locomotives, such as the 8801, 8894, 8897, 88951, 88952, 8104, 81561, and 81562.

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Since Marlin couplers are large, their ability to automatically couple in nearly every circumstance is excellent. The only time I've seen Marlin couplers fail is when the train collides with a car at rest at too high of a speed.

Because the couplers are so small and mounted differently on each car, the automatic coupling will fail. Now, this coupling problem isn't necessarily an indictment of MTL's design, but rather merely a limitation of any small coupler when not mounted consistently.

In fact, this photo shows two identical Full Throttle cylindrical hoppers, each with truck-mounted couplers, approaching one-another on a tight curve. Tip: When MTL couplers don't couple under ideal circumstances like this, it's usually due to a broken part, a damaged or missing spring, or compression from an overly-tight mounting screw.

Typically, the only remedy is to replace the coupler, or repair it by disassembling and rebuilding. But consider this photo, which shows an American Z Lines C44-9W and a Penned hopper attempting to couple.

While chassis-mounted couplers are more prototypical (i.e. like the real world), their orientation causes them to point outwards on a curve, away from the center of the track. The gargantuan C44 has a long overhang, causing the coupler to stray even further from the track center and making the problem even worse.

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Essentially, the conversion involves removing the old trucks (held in with a plastic peg) and the coupler (mounted with a tiny brass screw), and installing new MTL trucks with couplers (Micro-Trains #954 “Bettendorf”, #955 “Arch bar”, or #956 “Roller Bearing”). This conversion will improve automatic coupling on a curve, and may even help reduce derailments.

The downside is the cost (over $5.00 a pair), your time and aggravation, and the minor compromise in prototypical appearance and operation. For instance, Glen Chewier writes, “Truck-mounted MTL couplers can derail when backed over Marlin turnouts as the trucks get a sideways twisting force and the flanges then tend to pick frogs and points.

Not a problem on regular track with smooth rail joins, don't know about other brands of turnouts. Another solution that will reduce derailments, regardless of the mounting of the coupler, is to add a little weight to the more troublesome cars.

If a train accelerates and slows down rapidly, such as going down a hill, MTL couplers can easily let go. Marlin couplers do not appear to be susceptible to this, even though their own springs cause a similar “slinky” effect.

Note: ALL couplers and Full Throttle “Bowler Bucklers,” both equipped with plastic springs, eliminate the slinky effect. ALL's second-generation “Auto-Latch” couplers discussed here, in particular, do a much better job of staying coupled than their early first-generation units.

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Push and hold the button when the desired coupling is almost over the uncoupled, which will cause the uncoupled to rise about 1/8th-inch to mechanically trip tiny pins on the underside of the fishhooks, and the train will separate at that point. The downside is that Marlin uncouples are expensive, ugly, and installation requires wiring.

The magnetic field will cause the two “Magnetic” trip pins to separate, which will release the knuckles. It's an absolutely ingenious mechanism, although good reliability requires careful selection and installation of magnets, not to mention some practice.

To make magnetic uncoupling more reliable, you may need to adjust your trip pins. For a quick fix, line up all your MTL-equipped cars side-by-side, and look down from above to spot any pins that aren't pointing in the same direction as the rest.

The benefit is that magnets are much cheaper than Marlin uncoupling tracks, require no wiring of any kind, and are completely invisible once installed. It's probably not a good idea to install permanent magnets on your main- line, lest they accidentally uncouple a passing train that happens to exhibit a little of the slinky effect.

But electromagnets don't have this problem; they're only magnetized when activated remotely (somewhat like Marlin's mechanical uncouples). Tip: If you have rolling stock with both MTL and Marlin couplers, you'll most likely end up installing both types of uncouples in your layout.

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(Source: fr.tyrereviews.com)

I've installed magnets under my Marlin uncouples so the single section of track serves double-duty; see Converting Turnouts to Under-table Drive for details. Note: There are also tools designed especially for manually uncoupling two cars with MTL couplers without removing either of them from the tracks, but I've never used one.

To make a Marlin train look better, try replacing only those couplers that are visible, such as the one on the front of a locomotive and the one on the back of the last car. Tip: If you don't want to perform the conversion yourself, Scale Monster Trains sells transition cars, each equipped with an MTL knuckle coupler on one end and an MTL fishhook coupler on the other.

Most of Marlin's F7 units come with a nice-looking plow/pilot insert, which you can install only after removing the front coupler and spring. Likewise, some American Z Lines locomotives (such as their GP7) include detailed pilots that snap in place of the front truck-mounted couplers.

The procedure for changing couplers depends on where you're starting and where you want to end up: Micro-Trains #901 couplers, with the same D-shaped hole, are drop-in replacements that fit nearly all Marlin locomotives and rolling stock.

Then, slowly remove the Marlin coupler and spring with a pair of fine tweezers. If the engine has a tender, follow the instructions for Marlin rolling stock in the next section.

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(Examples include the 88490 GG1, the 88065 V 32 001, the Crocodile, the 8851 Swiss class AE 3/6 II, and many of their large tender-less steam engines.) Insert the chambered end of the trip pin into the small hole in the knuckle (the “fingers” if the coupler were a fist) until it just protrudes out of the top.

To prevent yours from disappearing, insert a piece of fine thread through the spring while working with it, and then carefully pull it out when assembly is complete. Gently tap the coupler to make sure it's springy and always returns to its center “home” position.

To expose the coupler housing, use a very sharp Act knife to carefully cut the welds and then gently pry off the cover. Make sure not to break any of the plastic pins; you'll need them later to reinstall the cover.

With the cover off, follow the directions for Marlin locomotives in the previous section. When you're done, put the metal cover back in place, fitting it over what's left of those three pins.

Then, using a soldering iron with a fine tip, carefully melt the three pins to re-weld the cover to the car. Some Marlin cars with chassis-mounted couplers (usually boxcars) have a slightly different system.

Like the car in this photo, the D-shaped pin is actually part of the body, and the coupler housing is integrated with the chassis. To expose the coupler, use a very sharp Act knife to carefully cut both welds, one on each end.

With the welds cut, slowly separate the chassis from the body only about 3/16” so that the pin clears the bottom of the coupler housing and most of the mouth, but doesn't exit the upper hole. Once you've removed the old coupler, follow the directions for Marlin locomotives in the previous section.

As described here, I'm not particularly fond of ALL couplers, though I admit most of my experience is with the first-generation units, and you might end up loving their second-generation “Auto-Latch” version more than Finding Nemo. Nonetheless, I swapped out all my ALL couplers for MTL couplers so my ALL cars and engines can couple with the rest of my North American rolling stock, stay coupled to one another on my layout, and support remote uncoupling.

(Since I use my ALL E8 to haul a set of Marlin SP Daylight passenger cars, I've opted for an MTL Marklin-style coupler for that engine, which I discuss here.) Things start getting interesting -- read “infuriating” -- when it comes to the ALL SD70M & SD75I diesel locomotives.

But the SD75I's rear coupler uses a proprietary snap-fit truck mount (see the tabs in this photo), and that complicates things. Essentially, you need to cut off the two limiter pins -- one on the knuckle and one on the lip -- as shown in this photo, or they won't fit inside the ALL housing.

Make your cuts flush, so the coupler can move freely when installed. Prop up the ALL housing with a “third hand” or a pair of locking tweezers, and then carefully assemble the modified Micro-Trains knuckle and lip, along with the MTL trip pin, as described here.

When you're done, your assembled coupler should look like this ; make sure to confirm the orientation of the MTL trip pin and the ALL mounting tabs. Test your work by gently tapping the coupler to make sure it's springy and always returns to its center “home” position.

The last step is to snap the assembled ALL/MTL hybrid coupler thingy back onto the rear truck of your locomotive, which should be rather easy. The #907 fits around a truck mount on most of MTL's older rolling stock with chassis-mounted couplers.

Place the #907 over the truck pivot, and align the plastic spring against the corner where the boxcar body overhangs the chassis. Start by consulting the Guide to MTL Couplers and Trucks to find the correct replacement; then just add an “-M” to the end of the part number.

Tip: trucks with fishhook couplers preinstalled are the easiest conversion path, but certainly not the cheapest. Tip: if you're considering buying just the bare-minimum of parts so that you can reassemble the couplers yourself, check out this section to make sure you're up to the task.

I installed a Micro-Trains fishhook coupler on my American Z Lines E8 locomotive, so it could tow my matching set of Marlin Southern Pacific “Daylight” passenger cars, and it was certainly much easier and cheaper than converting all the cars to MTL couplers. The photo shows a West model steam tender, which has nothing more than a brass rod extending out of the rear truck to couple to Marlin fishhook-equipped rolling stock.

Now, the nice thing about MTL couplers -- both the knuckle variety and the Marklin-compatible fishhook -- is that they can mount to any flat surface with nothing more than a screw. This means that your job is essentially to find a flat spot at the correct height, drill a hole, and then sink in the new coupler.

Although this approach wouldn't have involved any major surgery -- apart from cutting off the pin and bending the rod to set the coupler at the right height -- it would've been ugly as sin. Shorten the brass rod considerably and mount an MTL #905 to it so that it's somewhat tucked under the rear of the car.

Do away with the pin and rod entirely from the rear truck and mount the coupler on the chassis. Normally, I'm not enamored with chassis-mounted couplers because of the compromise in automatic coupling, but this is a short car with minimal overhang.

It's fairly clear from this photo that the top of the coupler box on the hopper is in line with the underside of the tender chassis. Tip: take digital photos of your own project and use them for reference, so you don't have to repeatedly reassemble and return to the rails to re-measure.

Luckily, this tender is short, which means only a small pivot, and thus room to install the coupler box between the flanges on the rear-most wheels. But the further out the coupler sticks, the worse it looks, and the greater the overhang (which can cause coupling problems).

(I wanted the hole hidden and the coupler housing flush with the rear deck, but no such luck here.) When you've found the ideal spot, mark the position of the screw hole with a fine-point Sharpie pen.

Tip: the MTL coupler housing isn't exactly symmetrical, but the mounting hole is dead center. Once you've marked the approximate position of the hole, use digital calipers to make sure it's perfectly centered.

On the West model tender, I had to trim a notch out of the overhang on the rear deck (shown in this photo). Don't use anything larger than a #61 drill bit (0.039” / 0.991 mm), though; the last thing you want is too big of a hole.

If anything, play it safe and start with an even smaller drill and slowly enlarge the hole until the tap fits. Tip: twist drill bits tend to “skate” across metal surfaces, which (apart from scarring the chassis) makes it difficult to get a hole precisely where you want it.

To prevent this, score the chassis by twisting the tip of a sharp Act knife (like you're turning a small screwdriver). I also find it helpful to clamp the drill (a Drexel tool in this case) to my bench and manipulate the part with my hands.

As you can see in this photo, the truck easily pivots to the angle required by the tightest turn (determined in step #2). If needed, add a thin shim and a slightly longer screw to lower the coupler.

To make Marlin US rolling stock look more prototypically accurate, you'll need to remove the Marlin couplers and trucks, drill new holes, cut new bolster pins, and mount Micro-Trains couplers and trucks. Harald Freudenreich has provided some excellent instructions for this conversion on his website.

You're going to use all five of your hands to assemble plastic and metal parts the size of hydrogen atoms into a self-contained mechanism that will provide trouble-free operation for years to come. The “Magnetic” trip pin keeps the two knuckle halves aligned and affords automatic uncoupling.

First, put the 702 jig upright on your work surface, and pull back the clamp, so the large spring is compressed. The large pin on the fixture should pierce the main hole in the coupler housing, as shown in this photo.

Insert the chambered end of the trip pin into the small hole in the knuckle until it just protrudes out of the top. The thin end of the trip pin should be pointing in the same direction as your right thumb as you insert it through the bottom of the knuckle.

When fully inserted, the trip pin should then look like an extended pinky finger as though you were sipping tea. Using fine tweezers to hold the two halves together like this, place them over the pin on the fixture so that the trip pin falls neatly in the triangular gap, and the knuckle points toward the fixture clamp.

This means that when you place the knuckle assembly into this sort of housing, the trip pinpoints up rather than hiding in the triangular gap of the #702 jig. Slowly release the fixture clamp so that it presses against the coupler, pushing the knuckle and lip firmly against the pin, as shown in this photo.

With the knuckle assembly held in place by the clamp, grab a spring with a fine pair of tweezers (or even the tip of an Act knife), and insert it into the space between the large pin and the rear of the knuckle/lip parts. To prevent yours from disappearing, insert a piece of fine thread through the spring while working with it, and then carefully pull it out when assembly is complete.

Gently tap the coupler to make sure it's springy and always returns to its center “home” position. If the broken coupler is truck-mounted on rolling stock, like the #954, #955, #956, or #971, you can swap out the entire truck/coupler combo for a new factory-assembled truck.

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