Rapid disintegration and weakening of ice shelves in North Greenland.

The glaciers of North Greenland are hosting enough ice to raise sea level by 2.1 m, and have long considered to be stable. This part of Greenland is buttressed by the last remaining ice shelves of the ice sheet. Here, we show that since 1978, ice shelves in North Greenland have lost more than 35% of their total volume, three of them collapsing completely. For the floating ice shelves that remain we observe a widespread increase in ice shelf mass losses, that are dominated by enhanced basal melting rates. Between 2000 and 2020, there was a widespread increase in basal melt rates that closely follows a rise in the ocean temperature. These glaciers are showing a direct dynamical response to ice shelf changes with retreating grounding lines and increased ice discharge. These results suggest that, under future projections of ocean thermal forcing, basal melting rates will continue to rise or remain at high level, which may have dramatic consequences for the stability of Greenlandic glaciers.

Absorption of the ω and ϕ mesons in nuclei.

Because of their long lifetimes, the ω and ϕ mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from 2H, C, Ti, Fe, and Pb targets. This Letter reports the first measurement of the ratio of nuclear transparencies for the e+e- channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels. The absorption of the ω meson is stronger than that reported by the CBELSA-TAPS experiment and cannot be explained by recent theoretical models.

Studies on the coordinate activity and liability of orotidylate phosphoribosyltransferase and decarboxylase in human erythrocytes, and the effects of allopurinol administration.

A coordinate relationship between the activities of two sequential enzymes in the de novo pyrimidine biosynthetic pathway has been demonstrated in human red cells. The two enzymes, orotidylate phosphoribosyltransferase and decarboxylase are responsible for the conversion of orotic acid to uridine-5'-monophosphate. Fractionation of red cells, on the basis of increase of specific gravity with cell age, has revealed that these two enzymes have a marked but equal degree of lability in the ageing red cell. It is postulated that orotidylate phosphoribosyltransferase and decarboxylase form an enzyme-enzyme complex, and that the sequential deficiency of these two enzymes in hereditary orotic aciduria may reflect a structural abnormality in this complex. In patients receiving allopurinol, the activities of both enzymes are coordinately increased, and this increase appears to be due, at least in part, to stabilization of both orotidylate phosphoribosyltransferase and decarboxylase in the ageing red cell. Allopurinol ribonucleotide is an in vitro inhibitor of orotidine-5'-monophosphate decarboxylase and requires the enzyme hypoxanthineguanine phosphoribosyltransferase for its synthesis. However, the administration of allopurinol to patients lacking this enzyme results in orotidinuria and these patients have elevated orotidylate phosphoribosyltransferase and decarboxylase activities in their erythrocytes. Evidence is presented that the chief metabolite of allopurinol, oxipurinol, with a 2,4-diketo pyrimidine ring is capable of acting as an analogue of orotic acid. It is postulated that the in vivo formation of oxipurinol ribonucleotide, catalyzed by orotidylate phosphoribosyltransferase, after allopurinol administration, leads to inhibition of orotidine-5'-monophosphate decarboxylase. This inhibition results in the urinary excretion of excessive amounts of orotidine and orotic acid, and "pseudo-substrate" stabilization of orotidylate phosphoribosyltransferase and decarboxylase.

Two immunoreactive binding proteins for insulin-like growth factors in human amniotic fluid: relationship to fetal maturity.

A binding protein for insulin-like growth factors (IGFs) has been purified from human amniotic fluid by IGF-I affinity chromatography and high performance reverse phase chromatography. This protein, with an apparent molecular mass of 28K nonreduced and 34K reduced, had an identical amino-terminus to a previously purified binding protein from amniotic fluid and to placental protein 12. The purified preparation (BP-28) bound both IGFs with high affinity [Ka, 6.55 +/- 2.24 (+/- SD) L/nmol for IGF-I and 3.23 +/- 1.05 L/nmol for IGF-II], with approximately 0.5 mol binding sites/mol BP-28 for either ligand. A 53K IGF-binding protein purified from human plasma (BP-53) did not cross-react in a RIA for BP-28, and BP-28 had less than 0.1% molar cross-reactivity in a RIA for BP-53. Human amniotic fluid reacted strongly in both assays. Fractionation of amniotic fluid samples by reverse phase chromatography showed that BP-28 and BP-53 immunoreactivities were present on separate proteins. In 40 third trimester amniotic fluid samples selected to cover a wide range of lecithin to sphingomyelin ratios, the mean concentrations of BP-28 and BP-53 were 37.6 +/- 17.6 (+/- SD) and 4.6 +/- 1.6 mg/L, respectively. Significant negative correlations were found between the levels of both BP-28 and BP-53 and the lecithin to sphingomyelin ratio, suggesting an association between the levels of both proteins and the degree of fetal maturity. A significant positive association was also found between the levels of BP-28 and BP-53. We conclude that the 28K IGF-binding protein from amniotic fluid, like the previously purified 53K binding protein, has high affinity for both IGF-I and IGF-II, that it coexists in amniotic fluid with BP-53 or a related protein, and that the levels of both proteins decline with increasing fetal maturity.

Stapler division of the omentum and small bowel mesentery in morbidly obese patients undergoing gastric bypass surgery.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) procedures can be technically demanding because of anatomical factors including fat distribution, organ fixation, and wound depth. We developed a technique using the Multifire Endo GIA 60 2.5 disposable surgical stapler which allows greater mobilization, less blood loss, and decreased operating time. METHODS: A disposable stapler designed for laparoscopic surgery was used to transect the gastro-colic omentum and small bowel mesentery in 67 morbidly obese patients undergoing RYGB. Generally, five to six stapler cartridges were needed for the transections. RESULTS: Stapler division of the gastro-colic omentum and small bowel mesentery decreased operating time by an average of 25 minutes. CONCLUSIONS: Applying principles of laparoscopic surgery to RYGB resulted in more efficient mobilization of the stomach and the small bowel mesentery, as well as decreased blood loss and operating time.

Influence of a forced air warming system on morbidly obese patients undergoing Roux-en-Y gastric bypass.

BACKGROUND: Hypothermia during and after major abdominal surgery decreases host defenses, increases the incidence of coagulopathy and may alter blood pressure, cardiac contractility and myocardial stability. METHODS: We designed a prospective randomized study to compare the benefits of a forced air warming system with warm blanket treatments in minimizing the effects of hypothermia on 64 morbidly obese patients undergoing Roux-en-Y gastric bypass. RESULTS: Patients in the forced air warming group (n = 32) had significantly higher perioperative body core temperature, lower central venous pressure and blood pressure readings, lower incidence of shivering, less blood loss intraoperatively and achieved a higher post anesthesia Aldrete Score than those patients in the warmed blanket group (n = 32). CONCLUSION: The forced air warming system is safe, cost effective and beneficial in minimizing the undesirable consequences of hypothermia in morbidly obese patients undergoing Roux-en-Y gastric bypass.

Marginal ulcer after gastric bypass: a prospective 3-year study of 173 patients.

BACKGROUND: Marginal ulceration (MU) after Roux-en-Y gastric bypass (RYGB) is a well-recognized complication. Its incidence varies between 1% and 16%. Factors associated with the development of MU include pouch size, pouch orientation, staple line integrity, and mucosal ischemia. Nonsteroidal anti-inflammatory drugs (NSAIDs) and Helicobacter pylori may also contribute to MU, but their mechanism of action in the RYGB patient has not been studied. METHODS: In 1994 a prospective 3-year study was designed to document the incidence of MU after near-total gastric bypass (NTGB). In this procedure the transected pouch was limited to the cardia, and the gastrojejunostomy was made along the greater curvature. A total of 173 patients entered the study. All patients who experienced postoperative nausea, vomiting, or abdominal pain underwent endoscopic examination of the pouch, stoma, and proximal Roux-en-Y limb. Gastrograffin studies were used within the first 2 weeks of operation. RESULTS: One year after operation, MU was not identified in any patient. At 3 years follow-up, MU was documented in one patient (0.6%) with a dilated gastric reservoir (60 cc). CONCLUSION: This study reviews the etiology, diagnosis, and treatment of MU in the RYGB patient and offers specific recommendations to reduce its occurrence. It also confirms a preliminary impression that NTGB is an effective operation in preventing MU formation.

The micropouch gastric bypass: technical considerations in primary and revisionary operations.

BACKGROUND: Roux-en-Y gastric bypass is an effective procedure for the long-term control of morbid obesity. An eventual revisionary operation, however, is necessary for some patients (0.8-29%). Redo procedures are required for pouch enlargement, staple-line dehiscence, or marginal ulceration. In 1994, the micropouch gastric bypass (MBG) was developed to eliminate the need for a repeat operation. Its design was based on two anatomical principles: 1) The fundus is elastic, aperistaltic, and may significantly dilate over time; 2) The proximal magenstrasse contains a high concentration of parietal cells, which potentiates the risk for marginal ulceration or gastroesophageal reflux after vertical pouch restriction. Construction of a micropouch limited to the gastric cardia avoids using the fundus and proximal lesser curvature, but requires a greater mobilization of the stomach and its peritoneal attachments. METHODS: Between February 1994 and February 2000, 1,120 patients underwent the MGB as a primary or revisionary operation. The fundus was mobilized completely, including transection of the left phreno-esophageal and gastrophrenic ligaments. The transected pouch was limited to the gastric cardia with 1 cm of fundus incorporated into the gastrojejunostomy stoma (GJS). RESULTS: There were 10 anastomotic leaks at the GJS (0.9%). All leaks sealed following surgical drainage or parenteral nutrition. One patient required re-operation (0.09%) for a dilated pouch and marginal ulceration. An additional patient (0.09%) developed a gastrogastric fistula secondary to a pharmacobezoar and stomal stenosis. CONCLUSION: With an appreciation for the finer anatomy of the proximal stomach and intra-abdominal esophagus, the micropouch can be constructed safely in both primary and redo procedures. The MGB, now in its seventh year, is durable and has, with rare exception, eliminated pouch enlargement, staple-line separation, reflux esophagitis, and marginal ulceration.

The estimation of plasma valproate by gas-liquid chromatography.

A gas chromatographic method for the plasma assay of the anticonvulsant, sodium valproate, is described. Derivatization is not necessary. 200 microliter plasma are required for a single estimation. The method involves a chloroform extraction of valproate and the internal standard, cyclopentane carboxylic acid, from acidified plasma. Gas-liquid chromatography using the stationary phase 10% SP-216-PS gives complete separation of valproate and the internal standard in eight minutes. The limit of detection is 20 mumol valproate/1 plasma (equivalent to 40 pmol on column). This is well below the lower therapeutic plasma level. The between-run precision of the method indicates a variation for each sample within+/-3% of its mean value.

Tuberculous lymphadenopathy: a collective review with a case report.

A collective review of tuberculous lymphadenopathy is presented with respect to incidence, pathogenesis, clinical manifestations, diagnosis, differential diagnosis, and treatment. A typical case report is also presented. A thorough history and physical examination, a purified protein derivative (PPD) skin test and acid-fast bacillus (AFB) stains, and histopathology of the node may provide useful information. Positive culture results are the only means of confirming the diagnosis and for distinguishing between tuberculous and non-tuberculous mycobacteria. Treatment, at least initially, must be guided by the physician's clinical suspicions.Although there remains debate as to what is the best method of treating mycobacterial lymphadenopathy, chemotherapy is essential. Excisional biopsy is recommended when feasible. The possible exception is when the diagnosis of mycobacterium tuberculosis is suggested by constitutional symptoms, characteristic chest x-ray findings, a positive PPD skin test, and positive culture of mycobacterium tuberculosis from another source such as sputum or gastric washings. This needle aspiration for diagnosis is applicable as done in the case report patient. Surgery is, therefore, reserved for excisional biopsy to establish the diagnosis if systemic disease is not suspected, and also for removal of grossly enlarged nodes. Incisional biopsy should be avoided if possible, as it can result in the formation of fistulous tracts.

Verbal and visual problems in reading disability.

Most individuals interested in reading disability favor the view that disordered language processing is the main cause of children's reading problems and that visual problems are seldom, if ever, responsible. Nevertheless, in a preliminary study (Eden, Stein, & Wood, 1993) we showed that visuospatial and oculomotor tests can be used to differentiate children with reading disabilities from nondisabled children. In the present study we investigated a larger sample of children to see if these findings held true. Using 93 children from the Bowman Gray Learning Disability Project (mean age = 11.3 years; 54 boys, 39 girls), we compared the phonological and visuospatial abilities of nondisabled children (children whose reading at fifth grade rated a Woodcock-Johnson reading standardized score between 85 and 115), and children with reading disability (whose reading standardized score was below 85 on the Woodcock-Johnson). In addition to performing poorly on verbal tests, the children with reading disability were significantly worse than nondisabled children at many visual and eye-movement tasks. A high proportion of the variance (68%) in reading ability of both the nondisabled children and those with reading disability could be predicted by combining visual and phonological scores in a multiple regression. These results provide further support for the hypothesis that reading disability may, to some extent, result from dysfunction of the visual and oculomotor systems.

Removal of fascial staples from the midline incision in patients undergoing a second laparotomy procedure.

A technique for removal of midline fascial staples is described. The staples are removed quickly and without significant anatomical distortion of the linea alba. In the majority of the patients a second row of fascial staples can be placed safely and in the same location as found in the original operation.

Current considerations in patients with coexistent diabetes and hypertension.

Primary health care providers frequently manage patients with diabetes and hypertension as co-morbid conditions. Because of the increased complexity and morbidity that occur when these conditions coexist, it is essential that practitioners remain aware of current treatment considerations and options, which are essential in helping patients manage this condition. This article reviews current considerations in the management and care of hypertension in diabetic patients. Possible differential diagnoses are considered, and current recommendations for essential nonpharmacological treatment approaches are reviewed. Particular emphasis is placed on the choice and initiation of pharmacological therapy for hypertension in the diabetic and the unique considerations necessary in this patient population. Standards of care for diabetic patients with the complication of hypertension are reviewed.

Search for medium modifications of the rho meson.

The photoproduction of vector mesons on various nuclei has been studied using the CLAS detector at Jefferson Laboratory. The vector mesons, rho, omega, and varphi, are observed via their decay to e;{+}e;{-}, in order to reduce the effects of final-state interactions in the nucleus. Of particular interest are possible in-medium effects on the properties of the rho meson. The rho mass spectrum is extracted from the data on various nuclei, 2H, C, Fe, and Ti. We observe no significant mass shift and some broadening consistent with expected collisional broadening for the rho meson.

Primary repair for closed lobar bronchus injury.

Primary repair in a 19-year-old male who sustained a closed injury to the right bronchus in an auto accident was performed successfully. A 1.5-cm tear was found at operation extending from the right lower lobe bronchus into its distal portion. Nine months later, the patient showed a patent airway with minimal granulation around one suture.

Brainstem electrical responses from selected tone pip stimuli.

Brainstem-electrical responses were obtained from 10 normal hearing adult subjects using frequency specific tone pips as stimuli. The four frequency specific tone pips (500, 1000, 2000, and 4000 Hz) were diamond shaped with a 2.5-msec rise/fall time. Each tone pip was presented at four intensity levels (70, 50, 30, and 10 dB hearing threshold level), and graphic recordings were made for each frequency at the specific intensity levels. Frequency specific Wave V intensity-latency functions were plotted, and these results were compared to tone pip data obtained in previous studies. In addition, suggested test procedures for obtaining tone pip brainstem-evoked responses under diagnostic conditions are discussed.