A putative ECF sigma factor gene, rpol, regulates siderophore production in Rhizobium leguminosarum.

A cloned Rhizobium leguminosarum gene, termed rpoI, when transferred to wild-type strains, caused overproduction of the siderophore vicibactin. An rpoI mutant was defective in Fe uptake but was unaffected in symbiotic N2 fixation. The RpoI gene product was similar in sequence to extra-cytoplasmic sigma factors of RNA polymerase. Transcription of rpoI was reduced in cells grown in medium that was replete with Fe.

Heterozygous C2-deficiency and myasthenia gravis.

Complement deficiency states in myasthenia gravis (MG) have not been reported previously. We describe a 19-year-old woman with typical MG and heterozygous C2 deficiency, along with HLA typing of the patient and her immediate family.

Parathyroid hyperplasia and carcinoma within one gland.

A 47-year-old Scottish woman vacationing in the United States presented with a serum calcium level greater than 20 mg/dl and a parathyroid hormone level 16 times greater than normal after a one-week history of severe vomiting and unrelenting abdominal pain. Surgical exploration of the thymus revealed the very rare association of a large (7 by 4 by 0.8 cm) parathyroid carcinoma adjacent to apparently normal parathyroid tissue, separated by a thin fibrous band. Two other hyperplastic and one normal parathyroid glands were also identified. Postoperatively, the patient became hypocalcemic and, for the past nine months, has received maintenance 1-alpha-hydroxycholecalciferol therapy (1 microgram per day) with normal calcium and barely detectable parathyroid hormone levels.

Cytomegalovirus infection blocks the beneficial effect of pretransplant blood transfusion on renal allograft survival.

Two factors which have gained attention as possible contributors to success of renal allografts are freedom from infection with cytomegalovirus (CMV) after transplant and administration of multiple blood transfusions pretransplant. In order to determine the interrelationship of these two variables, we analyzed 55 recipients of well matched (at least two antigens) cadaveric kidneys. In this study, absence of CMV infection and receipt of multiple transfusions both provided favorable outcomes. When patients were grouped by both factors, those who were free of infection and received multiple transfusions did significantly better than any other combination. Infection with CMV decreased the frequency of allograft survival in multiply transfused patients to a point intermediate between the above group and those who had not been multiply transfused. Since CMV infection can be predicted by measurements made pretransplant, and since up to one-quarter of CMV infection which develops post-transplant is transmitted with the allograft, administration of multiple transfusion to all patients and the use of donors who are free of latent CMV infection for CMV antibody-negative potential recipients should increase allograft success. For those potential recipients who already have latent CMV infection, further study will be necessary to determine what stimuli can be given pretransplant to prevent the interference with the beneficial effect of multiple transfusion.

Asymptomatic contralateral carotid artery stenosis: a five-year follow-up study following carotid endarterectomy.

Exactly 5 years after carotid endarterectomy for transient ischemic attacks (TIAs), the neurologic status of each of 67 patients whose angiograms demonstrated a contralateral carotid artery, two of which were fatal. One of these patients suffered antecedent TIAs. Two of the 50 patients (4%) without contralateral carotid stenosis experienced symptoms referable to the contralateral carotid; one of the 50 (2%) suffered a CVA without antecedent TIAs; and one of the 50 (2%) experienced a single TIA. Patients with a demonstrable contralateral carotid stenosis were at greater risk of developing contralateral symptoms than those without a stenosis [14 of the 67 versus two of the 50 (P < 0.01)]. There was no correlation between the incidence of new symptoms and the degree of contralateral stenosis. The 3% (two of the 67) incidence of stroke without antecedent TIAs on follow-up in those patients with a contralateral carotid stenosis suggests the following guideline: patients with contralateral carotid stenosis suggests the following guideline: patients with contralateral carotid artery stenosis can be advised to undergo staged carotid endarterectomies if the surgeon's stroke and morbidity rate is less than 3%.

The occluded renal artery.

Twenty-seven cases of renal artery occlusion are presented. In 16 patients the duration of occlusion could be determined and only two of 16 became hypertensive or experienced worsening of existing hypertension. Seven of 11 patients in whom the duration was unknown were hypertensive. Twelve patients were not treated and of these, ten are deceased with renal artery occlusion contributory in six deaths. Nine patients underwent nephrectomy and of eight hypertensive patients, five became normotensive. Six underwent revascularization and four were successful at 2 hours, 22 hours, 9 days, and 39 days, respectively, after occlusion. The experience leads us to conclude that viability can be proven only by direct observation and that revascularization with return of function and lowering of blood pressure is possible after prolonged periods of occlusion.

Bilateral internal carotid artery aneurysms.

Two patients were treated for bilateral internal carotid artery aneurysms. One had resection and restoration of continuity on the right side nine years after ligation of the left internal carotid artery. The second had sequential resection and reconstruction of both vessels. Complications of carotid aneurysms include embolization, rupture, and thrombosis. Preferred treatment is resection with reconstitution of the flow. Patients with carotid aneurysms should be investigated for similar lesions on the opposite side. Patients who have had one carotid aneurysm treated should be followed up for the possible occurrence of a contralateral aneurysm.

Renal artery aneurysm.

More and more renal artery aneurysms are being diagnosed, especially after the introduction of selective arteriography for the evaluation of renovascular hypertension. However, renal artery aneurysm still remains a rare entity. The pathogenesis of renal artery aneurysm is identical to the pathogenesis of arterial aneurysm in other arteries. Symptoms of aneurysm of the renal artery are dependent on a variety of factors, the most important of which are the size of the aneurysm, its location, and whether or not rupture has occurred. The indication for operation on renal artery aneurysm is rupture or threat of rupture. Herein we present a review of the literature and a report of 2 cases which exemplify the capabilities of the surgeon in dealing with such cases.

Management of acute ischemia of the upper extremity.

Records of 76 patients who presented with ischemia of the upper extremity from 1966 to 1981 were reviewed. Patients were divided into three groups according to cause: Group 1, emboli from the artery; Group 2, ischemia after catheter injury; and Group 3, ischemia due to lesions of the axillary and subclavian arteries. Management varied among the three groups. Long-term anticoagulation therapy was helpful in Group 1 patients in preventing reembolization. Forty percent of patients with catheter-related trauma required angioplasty of some sort in addition to embolectomy. Management of Group 3 patients was most difficult and the results least acceptable (three patients required amputation). Management of this type of ischemia must be individualized; it should vary according to the underlying disorder.

Clinical study of pheochromocytoma.

Seventeen patients underwent 22 operations for pheochromocytoma over a 26 year period. The patients included 11 in three kindreds of familial pheochromocytoma and 6 with sporadic tumors. The diagnosis was usually suggested by the patient's history. Confirmation of the diagnosis frequently required repeated testing for urinary or plasma catecholamines. Arteriography was the most effective method of preoperative tumor localization. Two tumors were proven nonfunctional. Others secreted either norepinephrine or epinephrine and norepinephrine. The familial patients showed a high incidence of multiple, bilateral and extraadrenal lesions. In contrast to previous reports, the familial tumors were found more often in the right than in the left adrenal gland. HL-A genotyping analysis of the sporadic and familial patients failed to demonstrate any HL-A antigen association or interdependent segregation of tumor and HL-A antigens within kindreds.