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Biomedical subjects

R A Malt

Publications and source records attributed to R A Malt.

At least 91 records · Page 5Linked to original sources
PubMed1982

Esophageal perforation.

Esophageal perforation can be caused by any instrument, device, or foreign body reaching the hypopharynx. Diagnosis remains difficult. If esophageal perforation is suspected, Gastrografin (meglucamine diatrizoate) swallow study, eventually followed by barium swallow study, is the most useful diagnostic test. Absolute rules cannot be made about the selection of nonoperative or surgical treatment. If diagnosed early, cervical or thoracic esophageal perforations can sometimes be treated conservatively if there are no signs of systemic sepsis. Recurrent leakage after surgical closure is not unusual. Local tissue flaps can reinforce the closure, particularly after delayed operation, thereby often avoiding the necessity for a reoperation or an esophageal exclusion.

Esophageal Diseases↗
PubMed1982

Prognostic factors for melanoma patients with lesions 0.76 - 1.69 mm in thickness. An appraisal of "thin" level IV lesions.

Fourteen variables were tested for their prognostic usefulness in 203 patients with clinical Stage I melanoma and primary tumor 0.76-169 mm thick. Only two variables, primary tumor location and level of invasion, were useful in predicting death from melanoma for these patients. Of the 12 deaths from melanoma, 11 occurred in patients with primary tumors located on the upper back, posterior arm, posterior neck, and posterior scalp (=BANS). There has been only one death from melanoma in 136 patients with melanoma located at other sites (11/67 vs 1/136, p less than 0.0001 Fisher's Exact Test). Of the 67 BANS patients, 51 had level II or level III lesions and five (10%0 died of melanoma. This compared with six deaths from melanoma in 16 patients (37.5%) with level IV BANS lesions (5/51 vs 6/16, p = 0.01 Fisher's Exact Test). The relatively high incidence of both melanoma deaths and regional node metastases for the BANS group merits consideration for testing the efficacy of elective regional node dissection for these patients.

Adult↗
PubMed1982

Prognostic factors for patients with clinical stage I melanoma of intermediate thickness (1.51 - 3.39 mm). A conceptual model for tumor growth and metastasis.

Fourteen variables were tested for their ability to predict visceral or bony metastases in 177 patients with clinical Stage I melanoma of intermediate thickness (1.51 - 3.39 mm). A Cox multivariate analysis yielded a combination of four variables that best predicted bony or visceral metastases for these patients: 1) mitoses greater than 6/min 2 (p = 0.0007), 2) location other than the forearm of leg) p = 0.009, 3) ulceration width greater than 3 mm (p = 0.04), 4) microscopic satellites (p = 0.05). The overall prognostic model chi square was 32.40 with 4 degrees of freedom (p less than 10 (-5). Combinations of the above variables were used to separate these patients into at least two risk groups. The high risk patients had at least a 35% or greater chance of developing visceral metastases within five years, while the low risk group had greater than an 85% chance of being disease free at five years. Criteria for the high risk group were as follows: 1) mitoses greater than 6/mm 2 in at least one area of the tumor, irrespective of primary tumor location, or 2) a melanoma located at some site other than the forearm or leg and histologic evidence in the primary tumor of either ulceration greater than 3 mm wide or microscopic satellites. The low risk group was defined as follows: 1) mitoses less than or equal to 6/mm 2 and a location on the leg or forearm, or 2) mitoses less than or equal to 6/mm 2 and the absence in histologic sections of the primary tumor of both microscopic satellites and ulceration greater then 3 mm wide. The number of patients in this series who did not undergo elective regional node dissection (N = 47) was probably too small to detect any benefit from this procedure. Based on survival rates from this and other studies, it is estimated that approximately 1500 patients with clinical Stage I melanoma of intermediate thickness in each arm of a randomized clinical trial would be needed to detect an increase in survival rates from elective regional node dissection.

Adult↗
PubMed1982

A multivariate analysis of prognostic factors for melanoma patients with lesions greater than or equal to 3.65 mm in thickness. The importance of revealing alternative Cox models.

Fourteen prognostic factors were examined in 79 patients with clinical Stage I melanoma greater than or equal to 3.65 mm in thickness. All nine patients with melanoma of the hands or feet died of melanoma. A Cox proportional hazards (multivariate) analysis of the remaining 70 patients showed that a combination of the following four variables best predicted bony or visceral metastases: 1) a nearly absent or minimal lymphocyte response at the base of the tumor, 2) histologic type other than superficial spreading melanoma, 3) location on the trunk, and 4) positive nodes or no initial node dissection. Ulceration and/or ulceration width were not useful in predicting outcome either singly or in combination with other variables. Patients with negative lymph nodes and primary tumors of the trunk, hands, and feet did not do better than patients with positive nodes at those sites. Conversely, non of 16 patients with negative lymph nodes and extremity melanomas (excluding the hands and feet) or head and neck melanomas developed visceral or bony metastases (i.e., five-year disease-free survival rate 100%).

Adult↗
PubMed1982

Preservation of arterial flow to the liver: goal in treatment of extrahepatic and post-traumatic intrahepatic aneurysms of the hepatic artery.

Post-traumatic intrahepatic aneurysms are frequent sources of intrahepatic and intrabiliary bleeding. The authors describe selective management of ten recent post-traumatic intrahepatic aneurysms, five extrahepatic aneurysms, and one ruptured hepatic artery in a patient with Ehlers-Danlos syndrome. Twelve patients had gastrointestinal bleeding or jaundice. Intraperitoneal rupture occurred twice. One aneurysm grew to 9 cm in diameter during nine years. Angiography should precede surgery whenever possible, and transcatheter occlusion should in general receive first priority. Aneurysms of the common hepatic artery usually can be excluded by proximal and distal ligation. Arterial bypass or serial angiographic occlusion is preferred for aneurysms of the proper hepatic artery. Intrahepatic aneurysms should usually be treated by angiographic thrombosis. Eigation of the proper hepatic artery or its branches should be reserved for exsanguination from unsuspected intrahepatic aneurysms encountered in the operating room. Lobectomy is required rarely.

Adolescent↗
PubMed1982

Metallothionein mRNA induction in mouse small bowel by oral cadmium and zinc.

Induction of metallothionein mRNA was investigated in organs of mice receiving oral zinc and cadmium. The low molecular weight, heat stability, and 30% cysteine content of metallothionein facilitated its detection in cell-free translation products analyzed by Sephadex G-50 chromatography and by gel electrophoresis. Native and heat-denatured [35S]cysteine-labeled polypeptides directed by poly(A)+ mRNA from organs of mice exposed orally to 3 mg CdCl2 or 15 mg ZnCl2 were compared with those of control mice. Although parenteral administration of CdCl2 (30 micrograms) did not elicit a measurable metallothionein mRNA accumulation in gut, oral administration of this metal induced intestinal metallothionein mRNA to high levels; translatable metallothionein mRNA was not detected in control organs. Five hours after oral CD or Zn, metallothionein constituted 12-17% of [35S]cysteine directed into protein by gut mRNA, and metallothionein mRNA was induced to similar levels in liver, kidney, and spleen of the same mice. After oral Zn, metallothionein mRNA levels in proximal jejunum were twice those in other regions of intestine. Metallothionein mRNA accumulates rapidly in small bowel after oral Zn and Cd; simultaneous induction in other mouse organs indicates a systemic response.

Animals↗
PubMed1982

Complications of splenic artery aneurysm other than intraperitoneal rupture.

Thirty-eight patients with aneurysms of the splenic artery were identified in the records of 11 years, but only one aneurysm was ruptured. Portal hypertension was found in nine patients (24%); in two of these the reaction surrounding the aneurysm prevented the construction of a patent splenorenal shunt or caused compartmented portal hypertension. One aneurysm encountered during the survey period and another encountered just after its conclusion ruptured into the stomach. There was a twofold overrepresentation of multiparous women. Intraperitoneal rupture is rare, except in pregnancy. If elective therapy is considered, angiography should be performed. Exclusion or resection of the aneurysm is advocated only for patients with symptomatic or ruptured aneurysms or (very rare) large aneurysms and for women of childbearing age. The spleen should be preserved, when possible. In high-risk patients occlusion of the aneurysm via an intra-arterial catheter should be considered. If the splenic artery aneurysm causes compartmented portal hypertension, splenectomy is indicated; if portal hypertension is general, the form of portasystemic decompression chosen should avoid the region of the aneurysm.

Adult↗
PubMed1982

Dimethylhydrazine-induced colonic neoplasia: dissociation from endogenous gastrin levels.

The potential tropic effect of gastrin in promoting colonic carcinogenesis was tested in rats (n = 133) with 6- to 16-fold variations in endogenous gastrin resulting from antrectomy or fundectomy, followed by 12 injections of 1,2-dimethylhydrazine (10 mg/kg). The incidence and grade of differentiation of resulting tumors, as well as the thickness, content of nucleic acids, and specific activity of DNA in colonic mucosa, were similar in both high-gastrin and low-gastrin animals and were unchanged from data in unoperated control animals receiving only the carcinogen. Long-term changes in endogenous gastrin concentration are not followed by colonic mucosal tropic effects, and gastrin does not act as a cofactor in dimethylhydrazine-induced carcinogenesis at this dosage.

1,2-Dimethylhydrazine↗
PubMed1981

Association of poly(adenylate)-deficient messenger ribonucleic acid with membranes in mouse kidney.

To describe further the metabolism of messenger ribonucleic acid (mRNA) in mouse kidney, we examined newly synthesized mRNA deficient in poly(adenylate) [poly(A)]. Approximately 50% of renal polysomal mRNA that labeled selectively in the presence of the pyrimidine analogue 5-fluoroorotic acid lacks or is deficient in poly(A) as defined by its ability to bind to poly(A) affinity columns. Nearly one-half of this poly(A)-deficient mRNA is associated uniquely with a cellular membrane fraction detected by sedimentation of renal cytoplasm in sucrose density gradients containing EDTA and nonionic detergents. Poly(A+) mRNA and poly(A)-deficient mRNA [poly(A-) mRNA] have similar modal sedimentation coefficients (20-22 S) and similar cytoplasmic distribution. Although 95% of newly synthesized poly(A+) mRNA is released in 10 mM EDTA as 20-90 S ribonucleoproteins from polysomes greater than 80 S, only 55% of poly(A)-deficient mRNA is released under the same conditions. Poly(A)-deficient mRNA recovered from greater than 80 S ribonucleoproteins resistant to EDTA treatment lacks ribosomal RNA, is similar in size to poly(A+) mRNA, and is associated with membranous structures, since 70% of poly(A)-deficient mRNA in EDTA-resistant ribonucleoproteins is released into the 20-80 S region by solubilizing membranes with 1% Triton X-100. These membrane-associated renal poly(A-) mRNAs could have unique coding or regulatory functions.

Animals↗
PubMed1981

Malignant melanoma patients with positive nodes and relatively good prognoses: microstaging retains prognostic significance in clinical stage I melanoma patients with metastases to regional nodes.

Fifteen variables were tested for their value in predicting recurrent disease in 46 clinical Stage I melanoma patients with metastases to regional nodes. A stepwise proportional hazards general linear model (Cox multivariate analysis) separated these melanoma patients with regional node metastases into at least two risk groups. Twenty patients in the relatively low-risk group had a five-year disease-free survival of 80% (in spite of having nodal metastases). This compares to a five-year disease-free survival of 17.5% for 26 patients in the high-risk group (P less than 0.001, Lee-Desu Statistic). Criteria for the high-risk group required that a patient have only one of the following two values: (1) The number of regional lymph nodes that contained tumor divided by the total number of nodes removed x 100% (percentage of positive nodes) greater than or equal to 20%; or (2) a primary tumor thickness of greater than 3.5 mm (regardless of node percentage). Conversely, patients in the low-risk group had neither of the above features. The high-risk group could further be stratified by the lymphocytic response at the base of the tumor. These findings have direct immediate application to the elective regional node dissection controversy and to adjuvant therapy studies containing these patients.

Adult↗
PubMed1981

Predominant role of bile in modulation of early postresectional enteric hyperplasia.

Pancreaticobiliary secretions modulate compensatory hyperplasia after proximal small-bowel resection. To investigate the individual contributions of bile and pancreatic juice, levels of nucleic acids in ileal mucosa of the rat were examined 48 hours after performance of jejunectomy with selective exclusion of bile or pancreatic juice. Exclusion of bile alone inhibited the postresectional increase in levels of RNA and DNA. Exclusion of pancreatic juice (but provision of bile) did not inhibit a rise in ileal RNA or DNA levels after jejunectomy. Presence of bile seems to be one of the major elements in the early stages of adaptive hyperplasia of the ileum.

Animals↗
PubMed1981

A prognostic model for clinical stage I melanoma of the trunk. Location near the midline is not an independent risk factor for recurrent disease.

Fifteen variables were studied for their usefulness in predicting recurrent disease in 254 patients with clinical stage I melanoma of the trunk. Thickness of the primary tumor correctly predicted outcome with an accuracy of 90 percent or greater in 176 patients with melanoma primaries with a thickness of less than 1.70 mm or 5.5 mm or greater. No other variables significantly increased predictive accuracy over these ranges of thickness. A Cox proportional hazards analysis of the remaining 78 patients with primary tumors 1.70 to 5.49 mm thick demonstrated that the following four variables functioned as independent risk factors for recurrent disease: (1) thickness of the primary tumor (p = 0.0005), (2) mitoses/mm2 greater than 6 (p = 0.006), (3) a nearly absent or minimal lymphocyte response at the base of the tumor (p = 0.009), and (4) location on the upper trunk (p = 0.03). Trunk lesions located near the midline did not have a worse prognosis than more lateral melanomas of similar thickness.

Female↗
PubMed1981

A prognostic model for clinical stage I melanoma of the upper extremity. The importance of anatomic subsites in predicting recurrent disease.

Thirteen variables were studied for their relative usefulness in predicting recurrent disease in 107 patients with clinical Stage I melanoma of the upper extremity. After a mean follow-up period of 54 months, the only patents who have had recurrent disease to date are those who primary lesions were located either on the hand or posterior upper arm. The five-year disease-free survival role for 44 patients with melanoma at these sites was 68%. None of 63 patients with melanoma located on the forearm of anterior upper arm have had recurrent disease (i.e., the five-year, disease-free survival rate was 100% (p = 0.00004), compared with the hand or posterior arm group). A Cox proportional hazards (multivariate) analysis demonstrated that two primary tumor histologic variable, thickness in millimeters and ulceration, interacted to produce the best prognostic model for those 44 patients with melanoma of the hand or posterior upper arm. Twenty-one patients with primary lesions at these sites had primary tumors less than 2.25 mm in thickness and no evidence of ulceration histologically. Their five-year, disease-free survival role was 95%. For the remaining 23 patients with primary tumors on the hand or posterior upper arm who had either histologic evidence of ulceration or primary tumors greater than or equal to 2.25 mm, the five-year disease-free survival rate was 37% (p = 0.002, compared with group nonulcerated, thin lesions). The excellent survival rate for patients with melanomas on the forearm or anterior upper arm was not completely explained by pathologic stage, by primary tumor thickness, or by histologic ulceration of the primary tumor.

Arm↗
PubMed1981

Operative and nonoperative management of esophageal perforations.

During a 21-year period, 72 patients were treated for esophageal perforations; the diagnosis was made only at postmortem examination in 13 other patients. Fifty-eight of 85 patients (68%) sustained iatrogenic perforations, 11 patients (13%) had "spontaneous" perforation, nine patients (11%) had foreign body related perforation, and seven patients (8%) had perforation caused by external trauma. Eleven cervical perforations, contained between the cervical paravertebral structures, plus eight thoracic perforations, contained in the mediastinum, were treated with antibiotics, intravenous hydration, and nasogastric drainage. The mortality rate after this nonoperative approach was 16% (3/19 patients). Indications for operative treatment in 53 patients were hydropneumothorax with mediastinal emphysema, sepsis, shock and respiratory failure. The operative mortality rate in these instances was 17% (9/53 patients). Six of the nine patients who died had been operated on more than 24 hours after the onset of symptoms. For cervical perforations the best results were obtained by drainage plus repair of the perforation (mortality rate: 0%; 0/10 patients) and for thoracic perforations by suturing supported by a pedicled pleural flap (mortality rate: 11%; 1/9 patients). Simple drainage of thoracic perforation was followed by a mortality rate of 43% (3/7 patients).

Esophageal Perforation↗