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Biomedical subjects

M A Sullivan

Publications and source records attributed to M A Sullivan.

At least 55 records · Page 3Linked to original sources

The chicken delta-crystallin gene family. Two genes of similar structure in close chromosomal approximation.

delta-Crystallin is a major protein product of the differentiated chicken lens. We have isolated two, non-allelic delta-crystallin genes using a recombinant bacteriophage/chicken genomic DNA library. There appear to be only these two delta-crystallin genes in the haploid chicken genome. Southern hybridization and R-loop analyses indicate that the two genes are oriented on the chromosome with similar 5'-3' polarity. delta 1, arbitrarily designated as the directionally 5' of the two genes, is 6.7 kilobases in length, while delta 2 is 9.2 kilobases. The two delta-crystallin genes are about 4.2 kilobases apart. Structurally, both genes are arranged in a similar and characteristic pattern of 17 exons/16 introns, as judged by electron microscopy. The delta-crystallin gene locus represents a simple model for the study of structural co-evolution and/or functional co-expression of two related genes within a developmentally modulated region of the genome.

Animals↗

Ultrasonography in the prenatal diagnosis of gastroschisis.

We have described a case in which prenatal ultrasonography showed a defect in the fetal abdominal wall. By further careful evaluation gastroschisis was diagnosed, allowing a planned delivery in a tertiary care center where specialized personnel were immediately available to treat the neonate.

Abdomen↗

Inflammatory bowel disease and cholelithiasis: the association in patients with an ileostomy.

Sixty-nine patients were evaluated prospectively by sonography and history to determine the presence of cholelithiasis. Sixteen patients (23%) had a positive diagnosis. A control group was also prospectively evaluated. We have determined that patients above age 50 with a permanent ileostomy are at statistically significant risk of having cholelithiasis, and their risk is greater than that of a control group matched for age and sex. Radiologists should recognize this association and carefully evaluate the gallbladder of any patient with a permanent ileostomy who has abdominal pain.

Cholelithiasis↗

Real-time pelvic ultrasonography as an adjunct to digital examination.

The authors suggest that diagnostic accuracy could be improved in 1% of cases by combining real-time ultrasound with digital examination of the pelvis or rectum. Differences of opinion between clinician and ultrasonologist regarding a possible pelvic mass can easily be settled. This technique can also be used to displace loops of bowel, help characterize congenital anomalies, and aid in the training of medical students and residents in obstetrics and gynecology.

Humans↗

The dexamethasone suppression test: identification of subtypes of depression.

In this study mean 4 p.m. cortisol levels were significantly higher in patients with major depression than in control subjects or in patients with bipolar depression or dysthymic-related disorders. Moreover, the distribution of values differed significantly among groups. Eighteen of 45 patients with major depression had cortisol levels of 10 micrograms/dl or more, compared with 2 of 20 bipolar depressed patients and 0 of 31 controls. Patients with very high cortisol levels (15 micrograms/dl or more) tended to fulfill criteria for major depression with mood-congruent psychosis. The distribution of values in the major depression group also suggested the existence of three major subgroups. The authors discuss the implications of these data.

Adolescent↗

Increasing the protection of newborn infants in cars.

Recently the American Academy of Pediatrics instituted a major campaign ("The First Ride--A Safe Ride") in order to encourage all parents to use an infant restraint seat for their newborn's first ride in an automobile--the ride home from the hospital. In the present study the effect of the behavior of the hospital staff on parents' use of infant restraint seats was examined. This study involved 30 mother-infant pairs who were selected sequentially from an obstetrics unit and randomly assigned to two groups. A control group was discharged from the obstetrics unit with no particular emphasis on car safety and no loaner restraint seat available. An experimental group was offered a loaner restraint seat at the time of discharge, with a staff person demonstrating how to put the infant into the restraint seat, how to carry the infant in the seat out to the car, and how to fasten the restraint seat in the automobile with the auto lap belt. Correct use of the loaner restraint seat on the first ride home was observed in 67% of the experimental mothers and in none (0%) of the control mothers. Although this difference was no longer significant at four- to six-week follow-up this study points out the short-term impact that hospital staff can have on the parents' use of restraint seats. Additional techniques are needed to maintain parents' use of restraint seats throughout childhood.

Automobiles↗

Abnormal colonic motility in progressive systemic sclerosis.

Progressive systemic sclerosis alters smooth muscle function throughout the gastrointestinal tract. In 10 consecutive patients with the disease, colonic spike activity and contractile activity were measured after a 1000-kcal meal, intramuscular injection of neostigmine, or intravenous injection of metoclopramide. The 1000-kcal meal stimulated a significant increase in spike and contractile activity in normal subjects. Nine of the 10 patients had no increase in motility after eating. Neostigmine or metoclopramide stimulated colonic spike (p less than 0.01) and contractile (p less than 0.02) activity in normal subjects and stimulated colonic motility (p less than 0.01) in four of 10 patients with less severe systemic manifestations of the disease (Group 1). The drugs had no effect on patients with severe progressive systemic sclerosis (Group II). The patients with severe scleroderma had significant gastrointestinal roentgenographic abnormalities and severe cardiac, renal, or pulmonary dysfunction. Four of six Group II patients died from the disease; all four had marked smooth muscle atrophy in the colonic wall. These findings suggest that the gastrocolonic response is absent early in the disease process and that the smooth muscle atrophy occurring with progression of the disease may lead to a more severe colonic motor disturbance.

Adult↗

Chicken lens crystallin DNA sequences show at least two delta-crystallin genes.

Restriction analysis of chicken DNA using probes derived from a cloned cDNA and analysis of cloned genomic DNA fragments containing delta-crystallin gene sequences have indicated the presence of at least two non-allelic genes for delta-crystallin, the first and principal crystallin synthesised in the embryonic chicken lens. Electron microscopic analyses of three cloned genomic fragments revealed that the delta-crystallin mRNA gene sequences are interrupted at least 14 times in one of the delta-crystallin genes.

Animals↗

Comparison of two delta-crystallin genes in the chicken.

Restriction endonuclease mapping and electron microscopy established that there are at least two nonallelic delta-crystallin genes in the chicken. The structure of a complete delta-crystallin gene has been deduced by analysis of five cloned fragments from the chicken genome. Fifteen intervening sequences compose approximately 80% of this gene; the other gene contains at least 14 intervening sequences. The mRNA gene sequences appear to be similar; at least 60% divergence was found between the intervening sequences of the two delta-crystallin genes. Insertions or deletions or both appear to be major events responsible for these differences.

Animals↗

Abnormal gastrocolic response in patients with intestinal pseudo-obstruction.

Gastrointestinal motility disturbances after endogenous stimuli have been demonstrated only in the esophagus and small intestine in patients with chronic idiopathic pseudo-obstruction. The 1,000-calorie meal stimulated a significant increase in spike and contractile activity in normal subjects. No increase in colonic spike or contractile activity occurred in patients with chronic idiopathic pseudo-obstruction even though colonic motility increased normally following the administration of neostigmine methylsulfate. These findings suggest that the normal response to eating is absent in patients with chronic idiopathic intestinal pseudo-obstruction even though their smooth muscle has been shown to be responsive to cholinergic stimulation. This loss of a gastrocolic response is further evidence for a disorder of the neurohumoral control mechanisms in patients with chronic idiopathic intestinal pseudo-obstruction.

Adult↗

Ultrasonic evaluation of the stomach, small bowel, and colon.

A characteristic sonographic pattern that suggests a bowel lesion is pathologically significant in over 90% of patients with this pattern. The authors call this pattern the "pseudokidney sign" because it superficially resembles the ultrasonic appearance of the kidney. Although found occasionally in normal persons, this characteristic pattern should always lead the sonographer to consider a bowel lesion. Additional radiographic examinations, such as an upper-gastrointestinal series, small-bowel studies, and barium-enema examinations, are advised for definitive diagnosis.

Adult↗

Colonic myoelectrical activity in irritable-bowel syndrome. Effect of eating and anticholinergics.

To determine the effect of a standard meal on colonic myoelectrical and motor activity in the irritable-bowel syndrome and to determine the effect of a single dose of an oral anticholinergic drug (clidinium bromide) on this response, we studied 10 patients. These patients showed a prolonged increase in both colonic spike (P less than 0.05) and motor activity (P less than 0.05) after eating as compared to normal subjects. Clidinium did not affect the frequency of colonic slow waves or the basal colonic spike and motor activity. However, the anticholinergic reduced the prolonged postprandial colonic spike and motor response in the patients and also reduced the postprandial increase in colonic contractions at 3 cycles per minute (P less than 0.05). These studies indicate that patients with the irritable-bowel syndrome show an abnormally prolonged post-prandial increase in colonic spike and motor activity. An anticholinergic drug reduces the duration and the magnitude of this abnormal colonic response.

Administration, Oral↗

Gastrointestinal myoelectrical activity in idiopathic intestinal pseudo-obstruction.

We evaluated the myoelectrical and motor function of the esophagus, small intestine, colon and anal sphincter in four patients with chronic idiopathic intestinal pseudo-obstruction. All patients had aperistalsis of the esophagus, with incomplete relaxation of the lower esophageal sphincter after swallowing or balloon distension. Duodenal slow-wave frequency was normal at 11.4+/-0.3 (+/-S.E.M.) cycles per minute. The patients did not have a normal increase in duodenal spike or motor activity after intestinal distension, but duodenal activity increased after stimulation with intravenous secretin. Colonic slow-wave activities were present at two frequencies, 6.2+/-0.3 and 3.3+/-0.1 cycles per minute. Neostigmine administration increased both colonic spike and motor activity normally. These studies suggest that in this disorder, physiologic neural responses to swallowing or intestinal distension are impaired but the intestinal smooth-muscle slow-wave activity and the spike and motor responses to exogenous neurohormonal stimulation are intact.

Adult↗