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T H Shawker

Publications and source records attributed to T H Shawker.

At least 19 recordsLinked to original sources
PubMed1996

Phase II trial of 5-fluorouracil, leucovorin, interferon-alpha-2a, and cisplatin as neoadjuvant chemotherapy for locally advanced esophageal carcinoma.

BACKGROUND: Most patients with esophageal carcinoma present with locally advanced disease and a poor prognosis. Surgery or radiation provides palliation for locally advanced esophageal carcinoma. The role of neoadjuvant therapy remains to be defined. We administered neoadjuvant chemotherapy consisting of 5-fluorouracil (5-FU), leucovorin, interferon-alpha, and cisplatin to 11 patients with locally advanced disease. METHODS: Eleven patients with squamous cell or adenocarcinoma of the esophagus were treated peroperatively with two to three cycles of combination chemotherapy. Nine patients underwent resection with curative intent. RESULTS: Six patients received three cycles of chemotherapy, and five received two. Dose reduction was necessary for two patients. One patient achieved a pathologic complete response, histologically confirmed. Of the eleven patients, two did not undergo surgery because of progressive disease during chemotherapy. Seven of the 9 patients relapsed after surgery and 2 have been disease free for 27 months. CONCLUSIONS: The combination 5-FU leucovorin, interferon-alpha-2a, and cisplatin administered in a neoadjuvant setting resulted in a median survival of 11.8 months with a median time to relapse of 7 months.

Adult↗
PubMed1996

Testicular adrenal rest tissue in congenital adrenal hyperplasia: findings at Gray-scale and color Doppler US.

PURPOSE: To study the ultrasound (US) features of scrotal adrenal rest tissue in congenital adrenal hyperplasia (CAH). MATERIALS AND METHODS: Gray-scale and color Doppler US examinations were performed of scrotal masses in eight patients. The masses were evaluated for size, location, echogenicity, sound attenuation, and vascularity. RESULTS: Seventeen intratesticular masses and one extratesticular mass were examined. All were hypoechoic except for one intratesticular mass that contained hyperechoic areas. Six masses demonstrated sound attenuation. The mediastinum testis was found in the center of 11 of the 17 intratesticular masses. At color Doppler US, six masses were hypervascular, seven were isovascular, and five were hypovascular relative to the normal testicle. All intratesticular masses contained vascular structures that entered them from the normal testis without change in course or caliber. Eleven masses showed a spoke-like pattern of converging vessels. CONCLUSION: The US features of scrotal adrenal rests assist diagnosis of CAH.

Adolescent↗
PubMed1995

Medullary nephrocalcinosis in nephropathic cystinosis.

Children with nephropathic cystinosis excrete large amounts of calcium and phosphate due to renal tubular Fanconi syndrome, and also receive substantial supplements of phosphate and alkalinizing agents. Since these constitute risk factors for nephrocalcinosis, we evaluated 41 children age 2 months to 15 years with nephropathic cystinosis and good renal function by performing retroperitoneal ultrasound examinations in a blinded fashion. We also retrospectively analyzed parameters of calcium and phosphate metabolism representing 216 person-years of data on these children. Fifteen children had no evidence of medullary nephrocalcinosis, while 18 had mild nephrocalcinosis, and 8 severe nephrocalcinosis; 5 had renal stones. Mean urine calcium and phosphate concentrations increased from 1.47 mM and 5.30 mM, respectively, in children without nephrocalcinosis to 1.60 mM and 5.69 mM in children with mild nephrocalcinosis to 1.66 mM and 6.19 mM in children with severe nephrocalcinosis. Mean urine pH ranged from 7.5 to 8.1. The mean (+/- SD) age of the 26 patients with nephrocalcinosis was 9.4 +/- 3.8 years compared with 5.1 +/- 3.8 years for those without nephrocalcinosis (P < 0.005). Serum calcium, phosphate, vitamin D, and parathyroid hormone did not correlate with frequency or degree of nephrocalcinosis. We conclude that nephrocalcinosis frequently accompanies nephropathic cystinosis, can be detected by ultrasound examination, and might be managed by reducing oral replacement of phosphate, calcium, vitamin D, and citrate. Consideration should be given to truncating phosphate replacement once bone growth ceases.

Adolescent↗
PubMed1995

Intraoperative ultrasound-directed resection of pituitary tumors.

Microadenomas of the pituitary vary in size, particularly those related to Cushing's disease. They are often not visualized on preoperative magnetic resonance (MR) imaging and may be difficult to find during surgical exploration of the pituitary. To enhance intraoperative localization of pituitary adenomas, we assessed the feasibility of using ultrasound to detect and localize pituitary tumors. Intraoperative ultrasound (IS) in the axial and sagittal planes was performed with an Intrascan system using a 12-MHz mechanically oscillating, end-firing transducer. Interpretation of the scans was performed by two individuals, who were usually blinded to the results of preoperative MR imaging or petrosal sinus sampling. Twenty-eight patients were examined. Eighteen of these patients had microadenomas (1.5-7 mm), all with Cushing's disease; nine had macroadenomas (10-20 mm), three of which were adrenocorticotropic hormone-secreting, three growth hormone-secreting, two thyroid-stimulating hormone-secreting, and one nonfunctioning; and one patient had an intrasellar craniopharyngioma. Normal sellar and parasellar structures, such as intrapituitary cysts, the intracavernous carotid arteries, and the diaphragma sella were easily visualized. Twenty-three of the 28 tumors, including 13 of the 18 microadenomas, were detected on IS (82% sensitivity). Tumors were seen as hyperechoic masses in 19 patients, mixed echogenicity in three, and isoechoic in one. In most macroadenomas IS allowed visualization of the interface between the tumor and the normal pituitary gland. These results indicate the potential of IS to aid the intraoperative localization and definition of pituitary tumors.

Adenoma↗
PubMed1995

High cervical intravagal hypercellular parathyroid gland as the etiology of severe persistent primary hyperparathyroidism.

The preoperative localization and operative management of a high cervical intravagal parathyroid adenoma in a young woman with severe persistent primary hyperparathyroidism is presented. The etiology of persistent hyperparathyroidism is most frequently a missed adenoma that is often in an ectopic location; of these, undescended adenomas represent a small but important proportion. If clinical suspicion and preoperative localization procedures suggest an undescended gland, a direct surgical approach using a high cervical incision and a unilateral exploration is often successful.

Adenoma↗
PubMed1994

Evaluation of color Doppler intraoperative ultrasound in parenchymal sparing renal surgery.

A renal parenchymal sparing surgical approach may be recommended in select patients with von Hippel-Lindau disease and renal cancer or in those with sporadic renal cancer and limited normal renal function. We performed 27 partial nephrectomies or enucleations in 17 patients with the use of intraoperative ultrasound to examine a subset of all renal lesions identified on preoperative examination. Of 24 lesions deep in the renal parenchyma that were examined, localized or identified with intraoperative ultrasound 18 were characterized as cystic and 6 as solid. The deep cystic lesions were characterized with ultrasound as benign simple cysts. Intraoperative ultrasound was used to locate and mark the line of incision over 2 impalpable solid renal cell carcinomas. Four solid renal cell tumors extended deep into the renal parenchyma where color Doppler intraoperative ultrasound helped to define the plane of dissection adjacent to vital vascular structures. Renal hypothermia was not used in 3 renal operations based on intraoperative ultrasound findings.

Adult↗
PubMed1994

Intraoperative US of the pituitary gland. Work in progress.

PURPOSE: To evaluate the use of ultrasound (US) of the pituitary gland during transsphenoidal surgery as a means of detecting microadenomas in patients with Cushing disease. MATERIALS AND METHODS: Thirteen patients with Cushing disease and one with acromegaly underwent US during transsphenoidal surgery. Mechanically oscillating transducers (10 MHz [n = 8] or 15 MHz [n = 6]) mounted on a 15-cm-long probe were used. RESULTS: Seven adenomas were definitely visualized, two were poorly seen, and four were overlooked. Small tumors (< 5 mm in diameter) tended to be hypoechoic; larger ones, hyperechoic. All four overlooked adenomas were imaged with the 15-MHz transducer. The cavernous sinuses and internal carotid arteries could be seen, but minimal invasion of the medial wall of the cavernous sinus could not. CONCLUSION: Pituitary microadenomas can be detected with transsphenoidal US; however, evaluation of larger series with instrumentation developed specifically for transsphenoidal application will be necessary to determine the ultimate value of this technique.

Acromegaly↗
PubMed1994

Development of luteinized graafian follicles in patients with karyotypically normal spontaneous premature ovarian failure.

Despite having amenorrhea and markedly elevated serum gonadotropin levels, some women with karyotypically normal spontaneous premature ovarian failure, nevertheless, have ovarian follicles that function intermittently. Graafian follicles capable of responding to these high FSH levels are faced with high serum LH levels as well, which might induce inappropriate luteinization and prevent normal follicle function. We examined this possibility using weekly blood sampling and sonography in 65 patients. Nearly 50% of our patients demonstrated ovarian follicle function [serum estradiol, > 183 pmol/L (50 pg/mL)] during a median of 4 months of observation (range, 2-6 months). However, during this observation, only 16% achieved an ovulatory serum progesterone level [> 9.5 nmol/L (3.0 ng/mL)]. We imaged an antral follicle by sonography in over 40% of patients (27 of 65), and serum estradiol was significantly greater when an antral follicle was present. The follicles in these patients were not functioning normally, however. In contrast to normal women, patients with ovarian failure had poor correlation between follicle diameter and serum estradiol. We biopsied these antral follicles in 6 patients and found luteinized Graafian follicles in all cases. Therefore, luteinized Graafian follicles account for at least 60% of the antral structures imaged (95% confidence limit). Thus, inappropriate luteinization of Graafian follicles appears to be a major pathophysiological mechanism in patients with karyotypically normal spontaneous premature ovarian failure.

Adult↗
PubMed1994

Symptomatic interleukin-2-induced cholecystopathy in patients with HIV infection.

OBJECTIVE: This study reports the clinical and radiologic findings in seven patients infected with HIV who had 10 consecutive episodes of symptomatic cholecystopathy induced by infusion of interleukin-2. SUBJECTS AND METHODS: Ten episodes of right upper quadrant pain associated with gallbladder wall thickening were seen in seven of 29 HIV-infected patients who received IV interleukin-2. Patients received 6-18 million IU/day of continuous interleukin-2 infusion for 5 days. Patients with right upper quadrant pain underwent sonographic examinations, which were interpreted prospectively. Medical records and previous sonographic studies were reviewed retrospectively. Follow-up was obtained through outpatient visits and sonography. RESULTS: Right upper quadrant pain during these 10 episodes of cholecystopathy usually developed 4-5 days after starting infusion of interleukin-2. Sonography during that time showed gallbladder wall thickening (mean thickness, 12.4 mm; range, 5-18 mm) and a wide variety of sonographic appearances. Tenderness during sonography was focal in six episodes, diffuse in one, and absent in three. Sludge was identified in one episode; calculi were not seen. Findings on radionuclide biliary scans were normal in three cases. Symptoms abated rapidly in every case after infusion of interleukin-2 was reduced or stopped. No surgery was necessary. When treatment was repeated, three patients had recurrent episodes, with clinical courses and sonographic aberrations showing little variance from the initial episodes. Follow-up sonography in three episodes showed a maximal thickness of the gallbladder wall of 4 mm. No patient had a history or laboratory evidence of intrinsic biliary disease. CONCLUSION: Symptomatic thickening of the gallbladder wall during infusion of interleukin-2 can exactly mimic other forms of acalculous cholecystitis, except that when associated with interleukin-2 the thickening is rapidly reversible and surgery is not required. Radionuclide scans can be useful in clinical decision making. The process appears to be benign, and cessation of interleukin-2 therapy, along with close clinical observation, appears to be the appropriate treatment.

Abdominal Pain↗
PubMed1994

Pathophysiology of syringomyelia associated with Chiari I malformation of the cerebellar tonsils. Implications for diagnosis and treatment.

The mechanisms previously proposed for the progression of syringomyelia associated with Chiari I malformation of the cerebellar tonsils are controversial, leave many clinical observations unexplained, and underlie the prevalence of different operations currently used as initial treatment. To explore the mechanism of syringomyelia progression in this setting, the authors used anatomical and dynamic (phase-contrast and phase-contrast cine) magnetic resonance (MR) imaging, and intraoperative ultrasonography to examine the anatomy and dynamics of movement of the cerebellar tonsils, the wall of the spinal cord surrounding the syrinx, and the movement of cerebrospinal fluid (CSF) and syrinx fluid at rest, during the respiratory and cardiac cycles, and during Valsalva maneuver in seven affected patients. In all patients the cerebellar tonsils occluded the subarachnoid space at the level of the foramen magnum. Syringomyelia extended from the cervical to the lower thoracic segment of the spinal cord. No patient had evidence of a patent communication between the fourth ventricle and the syrinx on anatomical MR images, dynamic MR images, or intraoperative ultrasound studies. Dynamic MR images of three patients revealed abrupt downward movement of the spinal CSF and the syrinx fluid during systole and upward movement during diastole, but limited movement of CSF across the foramen magnum during the cardiac cycle. Intraoperative ultrasound studies demonstrated abrupt downward movement of the cerebellar tonsils during systole that was synchronous with sudden constriction of the spinal cord and syrinx. Decompression of the foramen magnum was achieved via suboccipital craniectomy, laminectomy of C-1 and C-2, and dural grafting, leaving the arachnoid intact. Immediately after surgery, the pulsatile downward thrust of the tonsils and constriction of the spinal cord and syrinx disappeared. Syringomyelia resolved within 1 to 6 months after surgery in all patients. Observations by the authors suggest the following previously unrecognized mechanism for progression of syringomyelia associated with occlusion of the subarachnoid space at the foramen magnum. The brain expands as it fills with blood during systole, imparting a systolic pressure wave to the intracranial CSF that is accommodated in normal subjects by sudden movement of CSF from the basal cisterns to the upper portion of the spinal canal. With obstruction to rapid movement of CSF at the foramen magnum, the cerebellar tonsils, which plug the subarachnoid space posteriorly, move downward with each systolic pulse, acting as a piston on the partially isolated spinal CSF and producing a systolic pressure wave in the spinal CSF that acts on the surface of the spinal cord.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1994

Use of preoperative fine-needle aspiration in patients undergoing reoperation for primary hyperparathyroidism.

BACKGROUND: Neck reexploration for primary hyperparathyroidism has a lower success rate and greater morbidity than initial exploration because of scarring and distortion of tissue planes and the possibility of a parathyroid neoplasm located in an ectopic or unusual position. Although the use of standard noninvasive imaging studies for reoperative parathyroid surgical procedure is well accepted, the use of invasive studies to localize parathyroid neoplasms, particularly percutaneous aspiration of potential lesions, is controversial. In this report we analyze the results and morbidity in patients undergoing fine-needle aspiration before neck reexploration. METHODS: From 1982 to 1993, 255 patients underwent reexploration for persistent or recurrent hyperparathyroidism at the National Institutes of Health. Of these 255 patients 42 underwent 44 preoperative fine-needle aspirations by ultrasonography or computed tomography guidance in an attempt to localize a parathyroid neoplasm. The aspirated contents were then analyzed for parathyroid hormone content. RESULTS: Of the 44 aspirations 26 (59%) were true positives with no false positives. Of 18 negative fine-needle aspirations, 11 (25%) were false negatives, and seven (16%) were true negatives. The specificity and sensitivity of percutaneous fine-needle aspiration were 100% and 70%, respectively. CONCLUSIONS: Percutaneous fine-needle aspiration for parathyroid hormone is a safe, well-tolerated technique that is highly specific and allows a directed surgical resection avoiding further invasive workup when the aspirate is positive.

Adult↗
PubMed1994

Localization and operative management of undescended parathyroid adenomas in patients with persistent primary hyperparathyroidism.

BACKGROUND: Between 5% and 10% of patients who undergo cervical exploration for primary hyperparathyroidism will have persistent or recurrent hyperparathyroidism. Many of these patients have parathyroid tumors in unusual locations. One such site of ectopic parathyroid tissue is an undescended parathyroid adenoma at or superior to the carotid bifurcation. We describe our experience with the preoperative localization and surgical management of undescended parathyroid adenomas. METHODS: From 1982 to 1993 a consecutive series of 255 patients have undergone localization studies and surgical exploration for persistent or recurrent hyperparathyroidism at the Clinical Center of the National Institutes of Health. Operative strategy was determined by review of the patient's surgical history, disease reports, and data from localizing studies. Patients with an undescended parathyroid adenoma identified before the operation were examined with a direct approach high in the neck. Patients who did not have definitive preoperative localization were explored with the previous transverse cervical incision. RESULTS: Seventeen undescended parathyroid adenomas were identified in 255 patients. Thirteen (76%) of 17 patients had an undescended parathyroid adenoma precisely localized before the operation and were examined via a limited, oblique incision high in the neck anterior to the sternocleidomastoid muscle. In the 13 patients who had undergone accurate localization before the operation, the median operative time was 75 minutes compared with 235 minutes for four patients who did not have an undescended parathyroid adenoma identified before the operation and were examined via a previous transverse cervical incision. All patients were cured of their hyperparathyroidism. CONCLUSIONS: Undescended parathyroid adenomas were the cause of failed cervical exploration in 17 (7%) of 255 patients. Accurate preoperative localization of these lesions is possible in most cases with a combination of noninvasive and invasive modalities. Successful preoperative localization can convert a prolonged exploration of the neck and mediastinum into a brief, curative procedure with minimal morbidity.

Adenoma↗
PubMed1993

A prospective study of intraoperative methods to diagnose and resect duodenal gastrinomas.

OBJECTIVE: This study determined, prospectively, whether duodenotomy (DX) should be routinely performed in explorations for patients with Zollinger-Ellison syndrome (ZES). SUMMARY BACKGROUND DATA: Duodenal gastrinomas are now being found with increasing frequency in patients with Zollinger-Ellison syndrome. The surgical approach used to detect these tumors is controversial. Some recommend intraoperative endoscopy with transillumination (IOE) at surgery, while others recommend routine DX. METHODS: Beginning in 1989, the authors prospectively compared the ability of palpation, intraoperative ultrasound (IOUS), IOE, and DX (in that sequence) to detect gastrinomas in 35 consecutive patients with ZES. Each patient also underwent preoperative localization studies. RESULTS: Thirty-three of 35 patients (94%) had tumor detected and excised; duodenal gastrinomas were excised in 27 patients (77%). The average size of the duodenal tumors was 0.8 cm, significantly smaller (p < 0.005) than the pancreatic and lymph node tumors in this series. Standard palpation after a Kocher maneuver identified 19 of the 31 duodenal tumors (61%) in the 27 patients. IOUS revealed only eight duodenal tumors (26%) and no new lesions. IOE identified 20 duodenal gastrinomas (64%) and 6 new lesions. DX identified 31 duodenal tumors (100%) and 5 additional tumors. The morbidity rate was 17%. One patient had a duodenal fistula after operation (2.8%) and subsequently recovered. No patient died. CONCLUSIONS: These results demonstrate that the duodenum is the most common location for gastrinoma in patients with ZES (77%) and that DX to detect and remove duodenal gastrinomas should be routinely performed in all explorations for patients with ZES.

Adult↗
PubMed1993

Cerebellar and spinal hemangioblastomas: evaluation with intraoperative gray-scale color Doppler flow US.

Intraoperative gray-scale and color Doppler flow ultrasound (US) studies were performed in 12 patients with von Hippel-Lindau disease during surgical excision of hemangioblastomas. There were a total of 21 lesions: two were in the cerebellum and 19 were in the spinal cord. Twelve of the 19 spinal hemangioblastomas were hyperechoic to the spinal cord and thus were easily detected with gray-scale US. Color Doppler flow images provided improved delineation of all lesions compared with the images produced with standard gray-scale US. Seven of the 19 spinal lesions were detected only with color Doppler flow imaging because they were isoechoic to the normal spinal cord at gray-scale US. Color Doppler flow imaging enabled differentiation of the cysts and syrinx cavities associated with hemangioblastomas from dilated intraspinal vascular structures. In all cases, intraoperative color Doppler flow imaging facilitated the localization of hemangioblastomas during the neurosurgical procedure.

Adult↗
PubMed1992

A randomized, prospective trial of postoperative somatostatin analogue in patients with neuroendocrine tumors of the pancreas.

BACKGROUND: Pancreatic surgery is not uncommonly complicated by prolonged pancreatic drainage and fistula. Octreotide decreases pancreatic exocrine function and has been reported to improve closure of pancreatic and intestinal fistulae. This randomized, prospective trial was designed to evaluate the efficacy of postoperative octreotide in reducing pancreatic drainage and complications after resection of neuroendocrine tumors of the pancreas. METHODS: Patients with neuroendocrine tumors of the pancreas were entered into the study and randomized after operation to receive octreotide 150 micrograms subcutaneously every 8 hours or saline solution subcutaneously every 8 hours in a double-blinded fashion. Daily pancreatic drainage, total drainage, number of days to drain removal, and complications were recorded. RESULTS: Ten patients were given octreotide; eleven patients were given saline solution. The number of days to drain removal, daily drainage, and total drainage were not significantly different. Complications related to pancreatic drainage were not significantly different. CONCLUSIONS: Octreotide is not indicated for the routine postoperative management of patients with neuroendocrine tumors of the pancreas.

Adult↗