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Biomedical subjects

J A Hamlin

Publications and source records attributed to J A Hamlin.

At least 19 recordsLinked to original sources
PubMed2000

A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy. National Polyp Study Work Group.

BACKGROUND: After patients have undergone colonoscopic polypectomy, it is uncertain whether colonoscopic examination or a barium enema is the better method of surveillance. METHODS: As part of the National Polyp Study, we offered colonoscopic examination and double-contrast barium enema for surveillance to patients with newly diagnosed adenomatous polyps. Although barium enema was performed first, the endoscopist did not know the results. RESULTS: A total of 973 patients underwent one or more colonoscopic examinations for surveillance. In the case of 580 of these patients, we performed 862 paired colonoscopic examinations and barium-enema examinations that met the requirements of the protocol. The findings on barium enema were positive in 222 (26 percent) of the paired examinations, including 139 of the 392 colonoscopic examinations in which one or more polyps were detected (rate of detection, 35 percent; 95 percent confidence interval, 31 to 40 percent). The proportion of examinations in which adenomatous polyps were detected by barium enema colonoscopy was significantly related to the size of the adenomas (P=0.009); the rate was 32 percent for colonoscopic examinations in which the largest adenomas detected were 0.5 cm or less, 53 percent for those in which the largest adenomas detected were 0.6 to 1.0 cm, and 48 percent for those in which the largest adenomas detected exceeded 1.0 cm. Among the 139 paired examinations with positive results on barium enema and negative results on colonoscopic examination in the same location, 19 additional polyps, 12 of which were adenomas, were detected on colonoscopic reexamination. CONCLUSIONS: In patients who have undergone colonoscopic polypectomy, colonoscopic examination is a more effective method of surveillance than double-contrast barium enema.

Adenoma↗
PubMed1998

Herniography: a review of 333 herniograms.

We reviewed 333 consecutive herniographic studies in 306 patients for whom clinical data were available. Symptoms with either a negative or inconclusive physical examination (PE) were the most frequent reasons for requesting a herniogram. The herniogram was found to be more sensitive for the diagnosis of hernia, particularly inguinal, than PE. In 56 of 57 patients who came to operation the herniogram and the PE were concordant. In one patient, an incisional hernia was found at operation that had not been appreciated as such on the herniogram. We believe herniography should be used more frequently when the diagnosis of hernia is uncertain on PE, thereby reducing the incidence of unnecessary operative procedures.

Adolescent↗
PubMed1997

G-protein beta gamma subunit genes expressed in olfactory receptor neurons.

The expression of genes encoding G-protein beta gamma subunits was investigated in isolated olfactory receptor neurons from channel catfish. DNA sequencing of PCR products showed that the beta 1, beta 2, gamma 2 and gamma 3 genes were expressed in the neurons. Western blotting showed that at least three of these subunit proteins were expressed. This first analysis of the expression of beta gamma genes in olfactory receptor neurons suggests that these subunits may be involved in a variety of transduction events in these cells.

Amino Acid Sequence↗
PubMed1997

Renal angiomyolipomas: long-term follow-up of embolization for acute hemorrhage.

OBJECTIVE: To determine if elective, angiographically directed embolization of enlarged renal angiomyolipomas can be used to prevent future hemorrhagic episodes in patients with tuberous sclerosis and thus avoid nephrectomy. PATIENTS AND METHODS: Records were reviewed for all 5 patients who underwent elective, subtotal embolization of large, symptomatic angiomyolipomas at the authors' institution between 1975 and 1996. RESULTS: All 5 patients had tuberous sclerosis and bilateral renal angiomyolipomas. Initial embolization in these patients was performed in 1975, 1981, 1993 (2 patients) and 1994. In 1 patient only a single embolization session was required. In another, initial embolization on the left side was followed by embolization on the right 13 months later. Two patients underwent 2 sessions, and 1 patient had 4 sessions over a 13-year period. Subtotal embolization with particulate material led to a decrease in size of the most severely affected portion of the kidney. One large angiomyolipoma underwent sterile liquefaction after embolization; percutaneous catheter drainage was required. The embolization allowed subsequent partial nephrectomy in this patient. CONCLUSION: Embolization is effective for the long-term management of renal angiomyolipomas in patients with tuberous sclerosis; in this way nephrectomy and loss of renal function can usually be avoided.

Acute Disease↗
PubMed1997

The etiology of the adult indirect inguinal hernia: revisited.

It has generally been historically stated that indirect inguinal hernias develop only in patients who have a patient processus vaginalis that enlarges to become a hernia sac. Occasionally, this theory has been challenged but without any objective evidence. Herniography was performed by placing 50 mL of nonionic contrast material into the peritoneal cavity. The patient was then placed in a prone position with the head of the table elevated. Films of the inguinal fossae were obtained with the patient straining. The herniogram revealed a right indirect inguinal hernia. There was no left inguinal hernia, nor was there a patent processus vaginalis on the left side. Two years later, the patient developed left inguinal discomfort and swelling and was found to have a moderate-sized left inguinal hernia. At the time of operation, an indirect sac of moderate size was present. A mesh plug repair was performed. This case report is the first published objective evidence that, contrary to common thought, a patent processus vaginalis is not a necessary prerequisite to the development of an indirect inguinal hernia.

Hernia, Inguinal↗
PubMed1995

Herniography following indirect hernioplasty using the Marlex "mesh plug" technique.

In recent years, some surgeons have been performing indirect inguinal herniorrhaphies using a "mesh plug" technique without ligation or resection of the hernia sac. The authors have had an interest in herniography and questioned whether herniorrhaphy without ligation or resection of the indirect sac might result in a false positive herniogram or an abnormal filling defect within the peritoneal cavity. These questions were answered by the performance of herniography in five patients who had indirect hernias repaired by this method. No false positive herniograms were discovered, and the inverted sacs could not be identified within the peritoneal cavity. Therefore, herniography would still be a useful diagnostic tool in evaluating patients who have persistent or recurrent symptoms following operations wherein the hernia sac was left intact.

Contrast Media↗
PubMed1995

Herniography in symptomatic patients following inguinal hernia repair.

Patients with symptoms at the site of a previous inguinal hernia repair may constitute a diagnostic dilemma. The usefulness of herniography in the assessment of these patients was evaluated at 54 symptomatic sites in 46 subjects. Ten persistent or recurrent hernias were shown by herniography, only 2 of which were definitely detected on physical examination. The herniogram was normal at 44 sites, of which, on physical examination, 5 were equivocal and 1 was diagnosed as a definite hernia. On the unoperated-on or asymptomatic side, a total of 14 hernias were shown herniographically. Of these hernias, 8 were not detected on physical examination. Herniography was found to be more sensitive than physical examination in detecting hernias at the symptomatic, previously operated-on sites, as well as at the unoperated-on or asymptomatic sites. When a herniogram provides corroborative evidence that hernia has not recurred, the need for reexploration may be eliminated.

Adult↗
PubMed1994

Magnetic resonance imaging of the skull base.

Magnetic resonance (MR) imaging has made it possible to evaluate the skull base in one primary screening examination. In most cases, MR imaging also serves as the definitive imaging study. In some traumatic or congenital lesions or both, computed tomography (CT) and conventional radiographs may be preferred or may be needed to supplement the MR imaging examination. This article discusses the pathology of the skull base, particularly in the evaluation of suspected neoplasms. Optimal imaging of the skull base requires a minimum of two planes of section, typically with and without gadolinium contrast enhancement.

Bone Diseases↗
PubMed1992

Effects of angiographic needle size and subsequent catheter insertion on arterial walls. An in vitro experiment in human cadavers.

RATIONALE AND OBJECTIVES: It is widely believed that down-sizing catheters, and possibly needles, will decrease damage to the entry vessel in the performance of angiography. The purposes of this in vitro experiment are to determine if smaller needles produce less arterial wall damage than larger needles and to assess the influence of subsequent catheter insertion. METHODS: Each iliac artery pair from 35 fresh human cadavers was punctured three times with an 18-g needle and three times with a 21-g needle, for a total of 210 punctures. In two of each set of three, a 5- or 7-F dilator was passed. One hundred ninety-eight puncture tracts were usable and examined microscopically. They were graded on a scale of 1 to 3 in each of four categories: size of tract, margin irregularity, approximation of edges, and shape of tract. RESULTS: Chi-square analysis of the grading scores showed a significant shift of cases into lower damage grades when the smaller gauge needle was used for initial punctures (P < .0005). The subsequent insertion of a dilator, however, imposed further damage, such that the initial differences due to needle gauge were obliterated (P > .2). CONCLUSION: These data indicate that a 21-g needle produces less arterial wall damage than an 18-g needle, but that any safety conferred by the smaller needle is eliminated by the subsequent insertion of a 5- or 7-F catheter.

Adolescent↗
PubMed1990

Percutaneous endoscopic laser lithotripsy of retained stones in the left hepatic duct. The role of the surgeon.

A 35-year-old woman with a retained stone in a branch of the left hepatic duct was referred to us. The stone was discovered on the postoperative T-tube cholangiogram. A flexible ureteroscope was introduced into the duct, under fluoroscopic and direct endoscopic vision and the pulse dye laser was used successfully to disintegrate the calculus. The postoperative course was uneventful. We suggest that in certain selected cases, the pulsed dye laser might be useful in disintegrating stones sited in difficult positions.

Adult↗
PubMed1989

Large melanoma metastases to the gastrointestinal tract.

It is well known that malignant melanoma can metastasize widely. Although these metastases in the gastrointestinal tract usually appear as small 'bull's-eye' or 'target' lesions, there are a few reports of relatively large melanoma metastases. We report five cases of large melanoma lesions metastatic to the alimentary canal. We also emphasise the consideration of a thorough gastrointestinal tract evaluation in patients with malignant melanoma especially if they are symptomatic.

Aged↗
PubMed1986

Percutaneous biliary drainage: complications of 118 consecutive catheterizations.

We have reviewed our experience with 118 biliary catheterization procedures in 109 patients from 1979 to 1984. Major complications (septic shock, hemorrhage, subphrenic abscess, and formation of an arteriovenous fistula) occurred in five patients (4.2%), three of whom died (2.5%). Minor complications occurred in 41 patients. Our success rate using the procedure was 97%. The complications that occurred are described.

Bile Ducts↗