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Biomedical subjects

J H Thomas

Publications and source records attributed to J H Thomas.

At least 109 records · Page 6Linked to original sources
PubMed1989

Treatment options in early breast cancer.

Conservative management of early breast cancer with limited surgical excision and radiotherapy is now being accepted as a viable alternative to mutilating surgical procedures. In this paper, the major steps in the historical development of conservative management are traced, and the results of the current randomized trials are summarized. An innovative method used at the University of Kansas Medical Center delivers a "boost" dose to the tumor bed with interstitial Ir-192 immediately following resection of the primary tumor mass. The results obtained in terms of local control and cosmesis with this technique are presented, and the current state of the art is discussed.

Adult↗
PubMed1989

Advanced gastric leiomyosarcoma.

This is a retrospective review of twenty-two patients surgically treated for leiomyosarcoma. All but two patients had an advanced tumor of at least 8 cm size or involving contiguous structures. The most commonly performed operation was subtotal gastrectomy. The gastric resection required en bloc resection of contiguous structures in 10 patients. Fifteen patients with curative resection had a three year survival of 58 per cent. The overall group had a three year survival of 35 per cent. Advanced gastric leiomyosarcomas present a surgical challenge to complete resection, but when the procedure is accomplished the patient has a reasonable curative potential.

Adult↗
PubMed1988

Cosmetic results in early breast cancer treated with lumpectomy, peri-operative interstitial irradiation, and external beam radiation.

Patients with operable breast cancer were treated at the University of Kansas Medical Center with lumpectomy, peri-operative interstitial Iridium, and external beam radiotherapy, and concomitant adjuvant chemotherapy in a majority of node positive cases. Examination of the cosmetic results in 85 breasts followed for at least 2 years, at a median of 41 months revealed 20% to be excellent, 44% to be very good, 24% good, 9% fair, and 4% to have poor results. In this paper cosmesis is analyzed with reference to the size of the primary, its location, age of the patient, whether the patient received adjuvant chemotherapy, and whether the regional nodes were treated. In this group of patients, the size and the site of the primary, patient's age, and whether adjuvant chemotherapy was administered or not, did not adversely affect the aesthetic outcome. Treatment of the regional nodes gave a worse mean cosmetic score compared to the group in whom only the breast was treated (37.51 vs. 58.98 respectively, p less than 0.001). Among the 11 patients with fair/poor cosmesis, all had regional nodal treatment, 7/11 had inner quadrant lesions, and 7/11 had lesions greater than T1. Further follow-up and accrual would be needed to confirm our results and affirm if other factors would change.

Adult↗
PubMed1988

A comparison of diabetics and nondiabetics with threatened limb loss.

One hundred seventeen patients with threatened limb loss were evaluated. Seventy-three of these patients underwent vascular reconstruction. Diabetics had a significantly higher incidence of ischemic ulceration and gangrene when compared with nondiabetics. Nondiabetics typically presented with rest pain. The outcome of foot salvage surgery was evaluated by postoperative ankle-branchial indices as well as limb salvage rates. Ankle-brachial indices increased significantly in both groups. Fifty-five percent of the diabetics and 67 percent of the nondiabetics had a postoperative ankle-brachial index of 0.8 or greater. Overall foot salvage at 1 year was 84 percent. Foot salvage in patients with diabetes was 78 percent compared with 86 percent in nondiabetics. In this subset of patients with threatened limb loss confirmed by hemodynamic measurements, the results of vascular reconstruction were comparable in both diabetic and nondiabetic patients.

Adult↗
PubMed1988

Radioiodine therapy for differentiated thyroid carcinoma.

Radioiodine (iodine 131) is an effective form of adjuvant therapy that is frequently underutilized. A review of our recent experience was undertaken to assess the role of this treatment modality in the routine management of thyroid carcinoma. Over a 2-year period, 29 patients received adjuvant iodine 131 therapy. Ten of these patients (35 percent) were found to have local or distant metastasis by iodine-131 scan, and 7 (24 percent) had a metastatic lesion not suspected by operative findings or chest radiography. A complete response was obtained in 70 percent of the patients with metastatic disease. This study supports more frequent use of adjuvant radioiodine therapy in the management of differentiated thyroid carcinoma.

Adenocarcinoma↗
PubMed1988

Vascular graft selection.

Twenty to thirty per cent of patients with arterial injuries and some patients with venous injuries require interpositional grafting. The first choice of grafting material for both arterial and venous injuries is autogenous vein. Injuries to large vessels such as the aorta and superior vena cava may necessitate synthetic prostheses. Synthetic aortic prostheses have excellent long-term patency rates, but the same materials are much less likely to remain patent in the vena cava. Panel or spiral grafts constructed from saphenous vein appear to be the best replacement for this vessel. Autogenous veins are present in different diameters ranging from a mean of 6.4 mm in the saphenous vein to a mean of 1.8 cm in the internal jugular vein. The thickest autogenous vein is the saphenous vein, and thus it is preferred for medium-sized and small arteries. The authors prefer the larger 7.5-mm cephalic vein for replacement of medium-sized veins. In the absence of suitable saphenous vein, the cephalic vein is also the choice for arterial interposition grafts. Although there are few reports of the use of arterial autografts in vascular trauma, the surgeon should be aware that autografts may be ideal for vascular injuries in children and for isolated injuries with severe contamination. Finally, the use of synthetic grafts in injuries where adequate tissue coverage is not possible may result in immediate limb salvage, but the incidence of limb loss in this situation will be extremely high.

Arm Injuries↗
PubMed1988

Diverse effects of beta-tubulin mutations on microtubule formation and function.

We have used in vitro mutagenesis and gene replacement to construct five new cold-sensitive mutations in TUB2, the sole gene encoding beta-tubulin in the yeast Saccharomyces cerevisiae. These and one previously isolated tub2 mutant display diverse phenotypes that have allowed us to define the functions of yeast microtubules in vivo. At the restrictive temperature, all of the tub2 mutations inhibit chromosome segregation and block the mitotic cell cycle. However, different microtubule arrays are present in these arrested cells depending on the tub2 allele. One mutant (tub2-401) contains no detectable microtubules, two (tub2-403 and tub2-405) contain greatly diminished levels of both nuclear and cytoplasmic microtubules, one (tub2-104) contains predominantly nuclear microtubules, one (tub2-402) contains predominantly cytoplasmic microtubules, and one (tub2-404) contains prominent nuclear and cytoplasmic microtubule arrays. Using these mutants we demonstrate here that cytoplasmic microtubules are necessary for nuclear migration during the mitotic cell cycle and for nuclear migration and fusion during conjugation; only those mutants that possess cytoplasmic microtubules are able to perform these functions. We also show that microtubules are not required for secretory vesicle transport in yeast; bud growth and invertase secretion occur in cells which contain no microtubules.

Amino Acid Sequence↗
PubMed1988

Pitfalls in the diagnosis of pheochromocytoma.

Two patients were diagnosed as having pheochromocytoma based upon clinical findings, abnormal biochemical assays, and the presence of an adrenal mass. However, adrenalectomy in both cases revealed nonfunctioning cortical adenomas. Although both patients had some evidence of catecholamine excess, the early finding of an adrenal mass in each case appeared to confirm the diagnosis. In addition, selective venous assays resulted in false positive results in these patients. Interestingly, the selected venous assays falsely localized the catecholamine excess to the same side as the lesions found on CT. These cases demonstrate that localization studies should not be obtained prior to documentation of an unequivocal biochemical diagnosis of pheochromocytoma. If this principle is violated, an incidental cortical adenoma found on CT may be mistaken for a pheochromocytoma. Since there are multiple sources of error during selective venous sampling, it should not be used routinely in the initial evaluation of patients with pheochromocytoma.

Adenoma↗
PubMed1987

Intraoperative implantation radiation therapy plus lumpectomy for carcinoma of the breast.

The preponderance of evidence indicates that lumpectomy plus radiation therapy produces the same survival as modified radical mastectomy in patients with early breast cancer and further suggests that the local failure rate may be lower in the patients who undergo irradiation. In this series, patients were treated with immediate implantation of the tumor bed with iridium Ir 192. There have been two recurrences in the breast from 110 breast cancers (44% had a clinical stage greater than T1, and 41% had axillary-node involvement) in 107 patients followed up for four to 52 months (25.8 +/- 13.3 months [mean +/- SD]). These preliminary data suggest that local treatment failure can be minimized by aggressive, immediate intraoperative implantation of the tumor bed with iridium Ir 192.

Adult↗
PubMed1987

The critical hypogastric circulation.

Eleven patients had ischemic complications secondary to ligation, hypoperfusion, exclusion, or thrombosis of the hypogastric arteries after aortoiliac reconstruction or spontaneous aortoiliac thrombosis. Ligation of one hypogastric artery resulted in persistent ipsilateral buttock claudication in three patients. Bilateral acute hypogastric artery ischemia occurred in eight patients and resulted in paralysis in all eight patients, buttock necrosis in four patients, anal and bladder sphincteric dysfunction in two patients, and colorectal ischemia in three patients. Five of these patients (63 percent) died. The mortality rate was 100 percent when buttock necrosis developed. In most of these patients, the neurologic deficit suggested ischemic injury of the lumbosacral plexus rather than spinal cord ischemia. These complications occurred despite patent bypass grafts to the iliac or femoral vessels. These observations suggest that it is essential to maintain patency of the hypogastric vessels in all aortoiliac reconstructions.

Aged↗
PubMed1987

Diagnostic value of open lung biopsy in immunocompromised patients.

The records of 46 immunocompromised patients who presented with diffuse pulmonary infiltrates were reviewed to determine the role of open lung biopsy in their management. Fifty-two percent of these patients had underlying hematologic malignancies and 54 percent had received chemotherapy within 3 months prior to biopsy. Forty-six percent were receiving immunosuppressive doses of corticosteroids. A specific diagnosis was obtained in 30 of the 46 patients (65 percent). Fifteen of these patients had pulmonary infections. Nonspecific diagnoses were obtained in 16 of the 46 patients (45 percent). Therapy was altered in a total of 27 patients and 17 of these patients responded to treatment. Overall survival at 1 year was 41 percent. Forty-eight percent of the patients in whom therapy was changed survived 1 year, and 31 percent of the patients in whom therapy was not changed survived 1 year. No deaths were attributable to the operative procedure. The complication rate was acceptable. Open lung biopsy is an important technique in evaluating and determining therapy in immunocompromised patients who present with diffuse pulmonary infiltrates.

Adolescent↗
PubMed1987

Perioperative interstitial irradiation in the conservative management of early breast cancer.

Conservation of the breast in early breast cancer with limited resection and radiation is proving to be as effective as modified radical mastectomy in survival and in loco-regional control. Management at the University of Kansas Medical Center consists of an interstitial implant at the time of lumpectomy to facilitate perioperative irradiation with Iridium-192 to the tumor bed. An axillary node dissection is also performed at that time. Two to 3 weeks later external beam irradiation is delivered to the entire breast. One hundred and twenty-three breasts in 120 patients have been treated between June 1982 and June 1986. There were 49 pathological Stage I, 63 Stage II, 8 Stage III carcinomas, and 3 carcinomas in situ, consisting of 72 T1, 43 T2, 5 T3, and 3 TIS lesions. Patients have been followed for a median of 30 months. One patient had a "true" recurrence in the breast. Another patient developed recurrence in a different quadrant. Ninety percent of the patients had good to excellent cosmetic results, 7% were considered fair, and 3% had poor results. Seven patients developed mild arm edema, 4 were found to have moderate edema, and 1 had severe arm edema. Our preliminary results indicate that interstitial irradiation immediately after excision results in excellent local control, with very satisfactory cosmesis and no morbidity due to the simultaneous excision and irradiation.

Adult↗
PubMed1987

A Saccharomyces cerevisiae genomic plasmid bank based on a centromere-containing shuttle vector.

A set of genomic plasmid banks was constructed using the centromere-containing yeast shuttle vector YCp50. The centromere-containing vector is useful for the isolation of genes that are toxic to yeast when present in high copy number. Fourteen independent banks were prepared each with an average representation of two to three times the yeast genome. Any individual plasmid from a given bank is guaranteed to be of independent origin from plasmids obtained from each of the other banks. The banks were constructed from three different size classes of DNA fragments that resulted from varying conditions of partial digestion with Sau3A. This avoided the bias caused by differential sensitivity of sites to cleavage with Sau3A. Insert DNA is sufficiently large that most genes will be present in the set of plasmid banks at a frequency of about 0.1%.

Centromere↗
PubMed1987

Breast conservation treatment with perioperative interstitial irradiation.

Limited resection of the breast combined with radiation has proved to be as effective as more radical surgery in treating early breast cancer. At the University of Kansas Medical Center, the radiotherapy consists of an interstitial implant at the time of lumpectomy to deliver an interstitial boost dose to the tumor bed with iridium-192 immediately following the surgical procedure. An axillary node dissection is also performed at the time of lumpectomy. A dose of 2,000 cGy is delivered to the tumor bed between 40 and 60 h. Two to three weeks later, 4,500-5,000 cGy is delivered to the entire breast with external beam radiation over 5-5.5 weeks. One hundred breasts in 98 patients were so treated between June 1982 and February 1986, with 2 carcinomas in situ, 40 stage I, 51 stage II, and 7 stage III cancers, consisting of 2 TIS, 54 T1, 39 T2, and 5 T3 lesions. Locoregional control with a median follow-up of 31 months was 98%. One recurrence was in a different quadrant, and the other revealed predominantly the in situ component. Immediate implant did not compromise wound healing or cosmesis. The cosmetic result was graded as good to excellent in 88% of the breasts. Our preliminary results appear to suggest a better local control with immediate interstitial irradiation.

Adult↗
PubMed1986

A gene required for the separation of chromosomes on the spindle apparatus in yeast.

We describe the phenotypes caused by a cold-sensitive lethal mutation (ndc1-1) that defines the NDC1 gene of yeast. Incubation of ndc1-1 at a nonpermissive temperature causes failure of chromosome separation in mitosis but does not block the cell cycle. This defect results in an asymmetric cell division in which one daughter cell doubles in ploidy and the other inherits no chromosomes. The spindle poles are properly segregated to the two daughter cells. The primary visible defect is that the chromosomes remain associated with only one pole, and are thus delivered to one daughter cell. Meiosis II, but not meiosis I, is sensitive to the ndc1-1 defect, suggesting that NDC1 is required for some feature common to mitosis and meiosis II. ndc1-1 appears to define a new class of cell cycle gene required for the attachment of chromosomes to the spindle pole.

Aneuploidy↗