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Biomedical subjects

B Roberts

Publications and source records attributed to B Roberts.

At least 163 records · Page 9Linked to original sources
PubMed1984

Endocrine status versus chronologic age as predictors of altered luteinizing hormone secretion in the "aging" rat.

LH release in response to GnRH injected at 1400 h was measured in young (3-4 months), middle-aged (10-11 months), and old (19-20 months) female rats. Data were compared when animals were grouped by chronological age or according to their vaginal smear pattern 3-4 weeks before treatment, i.e. regular 4-day cycles, constant vaginal cornification (CVC), or persistently leukocytic smears (PL). Compared to young, regularly cycling females (injected on vaginal estrus or diestrus II), the amount of LH released by all age groups with CVC or PL smears was significantly diminished. However, regardless of age, the amount of LH released by CVC females was similar for each dose of GnRH. Similarly, there was no difference in the amount of LH released by the young, middle-aged, and old PL females at each dose of GnRH. Finally, the amount of LH released by the CVC females was uniformly higher than the amount of LH released by age-matched PL females. In contrast, comparison of LH release after GnRH injection in young and middle-aged rats with regular 4-day vaginal cycles showed that the middle-aged rats released significantly less LH on proestrus. These data suggest that changes in the ability of the pituitary to release LH in the older noncycling female rat occurs as a consequence of the altered endocrine status in the animal and not as a result of the chronological age per se. Changes in the ability of the pituitary of the middle-aged, regularly cycling female rat to release LH in response to GnRH may contribute to the age-related disruption of regular ovarian cycling.

Aging↗
PubMed1982

Current status of percutaneous transluminal angioplasty.

With the development of a dilating balloon catheter that permits percutaneous treatment of many arterial stenoses and some occlusions, a definite advance in the therapy of peripheral vascular disease has been made. It is still too early to be certain what ultimate position this means of therapy will take in the overall treatment of vascular disease, as its use is still being extended and long-term results are not yet clearly known. When compared with surgical therapy, however, it has some striking advantages, although the durability of its effect appears to be less. Despite the fact that more time and experience are needed before its ultimate position is established, we believe that the evidence to date warrants inclusion of this form of therapy in the armamentarium of every major vascular center.

Angiography↗
PubMed1982

Treatment of acute peripheral arterial and graft thromboses with low-dose streptokinase.

Seventeen patients with acute peripheral arterial or graft occlusion were treated with local low-dose intra-arterial streptokinase. The series includes eight patients with native vessel occlusion, six patients with vein graft occlusion, two patients with prosthetic graft occlusion, and one patient with renal allograft artery occlusion. The duration of occlusion prior to streptokinase therapy varied from 2 hours to 5 weeks. The treatment was successful in 14 of the 17 instances. In conjunction with the successful thrombolytic therapy, percutaneous transluminal angioplasty was performed subsequently in 10 of the patients and reconstructive surgery in three. One major and five minor hemorrhagic complications occurred and were considered to be secondary to the streptokinase therapy. In follow-up of up to 9 months, 11 of the 14 successfully treated patients continued to have a good result, without any indication of recurrent arterial occlusion. Two patients have died of causes unrelated to thrombolytic therapy and one patient required bypass grafting for recurrent thrombosis. None of the successfully treated patients lost a limb. Of the three patients in whom thrombolysis was unsuccessful, two required amputation. Local intra-arterial low-dose streptokinase appears to be a promising alternative to immediate operative treatment in carefully selected cases of arterial occlusion. Definitive treatment of the underlying cause of the thrombus usually is required and changes of success may be enhanced by the thrombolytic therapy.

Adult↗
PubMed1981

Balloon-catheter dilation as an adjunct to arterial surgery.

Balloon-catheter dilation of arterial stenoses and/or occlusions has been found to be helpful when used both as an adjunct to arterial surgery and as definitive treatment. Used preoperatively, it enables the extent of surgery to be limited and may improve the patient's general condition and ability to undergo surgery; such is seen when renal or mesenteric vessels are dilated preoperatively. During surgery, it can be used to augment the surgery, particularly in an area that is difficult to expose or out of the operative field. Postoperatively, it is often useful in maintaining patency of a graft or its inflow and outflow tract. Judicious use of this modality can enhance arterial surgery and improve results.

Arterial Occlusive Diseases↗
PubMed1981

Transluminal angioplasty of the iliac and femoral arteries: follow-up results without anticoagulation.

With the advent of the angiographic balloon catheter, transluminal angioplasty has become a more effective procedure for the alleviation of symptoms of peripheral ischemia. In the past two and a half years we have performed this procedure on over 208 iliac and femoral arteries. One hundred twenty iliac arteries were dilated. Of these, 86% remained patent at one year and 83% at two years. Eighty-eight femoral arteries were dilated. Of these, 75% remained patent at one year and 67% at two years. These vessel survival rates are slightly less than those following surgery. However, the morbidity from transluminal angioplasty is very low and the mortality is essentially zero.

Adult↗
PubMed1981

Value of routine vascular laboratory studies to identify vein graft stenosis.

Thirty-three stenotic lesions were found in 30 vein grafts (17 femoral-popliteal, 13 femoral-tibial) 3 months to 8 years postoperatively--77% appeared within 1 year of surgery. Seventeen (57%) of the patients presented with normal distal pulses, and a similar number were asymptomatic. Only eight (26%) presented with unequivocal clinical evidence of graft stenosis based on decreased pulses and return of ischemic symptoms. Forty percent were completely asymptomatic with normal distal pulses. The mean postoperative ankle systolic pressure index (ASPI) was 0.83 +%- 0.03 (SEM); it fell to 0.57 +/- 0.04 (SEM) when stenosis developed. The peripheral vascular laboratory measurements were the key factor influencing the decision for repeat arteriography in many of these patients and reinforced the need for a repeat arteriogram when the clinical diagnosis was unclear. Early diagnosis of vein graft lesions prior to graft occlusions allowed 24 of 30 of these stenotic grafts to be treated primarily by percutaneous transluminal angioplasty (PTA); 80% remained patent 24 months after PTA. Since most vein graft stenoses can be treated by such a simple, nonoperative technique (PTA), every effort should be made to diagnose and treat lesions prior to graft occlusion. Our experience indicates that frequent vascular laboratory measurements of ASPI are more sensitive then clinical examinations in detecting early vein graft stenosis.

Angioplasty, Balloon↗
PubMed1980

Protection of laying hens against infectious bronchitis with inactivated emulsion vaccines.

Commercially-reared laying chickens were challenged at 31 weeks of age with a virulent infectious bronchitis (IB) virus. They showed a sharp drop in egg production, despite having been vaccinated at four and eight weeks old with live attenuated IB vaccines to a recommended schedule. In contrast, similar birds that had been further immunised at point-of-lay with inactivated oil emulsion IB vaccine, or with a combined IB/Newcastle disease (ND) emulsion vaccine, showed no detectable fall in egg production after the same challenge. Unvaccinated susceptible specific pathogen-free birds challenged at the same time stopped laying almost completely. In the birds revaccinated with emulsion vaccine, measurement of haemagglutination inhibition antibody levels to IB showed their geometric mean titres to be raised from less than 5 log2 at the time of vaccination to over 10 log2 four weeks later. Their antibody levels did not rise further followining the IB challenge whereas in the birds that had not been revaccinated antibody rises to nearly 10 log2 were detected after the same challenge. For pullets vaccinated earlier with live IB vaccine, revaccination with inactivated IB or IB/ND oil emulsion vaccine at point-of-lay provides a safe and effective way of protecting their egg production against IB infection.

Animals↗
PubMed1980

Balloon dilation of iliac stenosis with distal arterial surgery.

Seven patients with concomitant atherosclerotic iliac stenosis and femoral artery occlusive disease were treated with polyvinyl balloon catheter dilation of the iliac artery and subsequent distal operative arterial reconstruction. The iliac lesions were short, localized, common and external iliac stenoses and the femoral lesions were superficial femoral artery occlusions in six patients and a common femoral occlusion in another. All seven iliac stenoses were successfully dilated. Subsequent operative femoral artery reconstruction was successful in these patients, with restoration of popliteal or pedal pulses and relief of ischemic symptoms over a follow-up period of two to 14 months. One patient's femoral popliteal bypass graft thrombosed four months postoperatively.

Aged↗
PubMed1980

Early experience with percutaneous transluminal angioplasty using a vinyl balloon catheter.

The technique of transluminal dilatation of arterial stenoses has been greatly facilitated with the recent development of the vinyl balloon catheter by Gruntzig. Since these catheters became available to us in early 1978, we have utilized them to attempt dilatation of 62 arteries, including iliac, femoral and renal vessels. Immediate success was achieved in 57 of these vessels. There were five early complications (two distal embolizations and three prompt occlusions) and three late complications (two restenoses and one occlusion at ten days). The occlusions were all treated promptly surgically with good results and the stenoses redilated. Noninvasive pressure measurements were obtained on all patients whose iliac or femoral arteries were dilated both before and after the procedure, with objective improvement demonstrated by this method. The procedure itself is well tolerated by patients. It involves only minimal discomfort and risk and a markedly shortened hospital stay. The procedure can be easily accomplished by physicians who are thoroughly familiar with routine femoral catheterization techniques and it is believed that this technique will have a definite place in the future therapy of many cases of arterial stenosis.

Arterial Occlusive Diseases↗
PubMed1980

Pulmonary alveolar epithelial permeability in surgically induced hemorrhagic pancreatitis in dogs.

The adult respiratory distress syndrome has been associated with acute pancreatitis in 5-8% of patients. to determine, in a quantitative manner, the effects of acute, hemorrhagic pancreatitis on alveolar epithelial permeability, we studied two groups of dogs (group 1 - sham-operated, 7 dogs; group 2 - surgically induced pancreatitis, 7 dogs) and measured the flux of 10,000-20,000 molecular weight dextran and albumin (69,000 molecular weight), from the blood to the saline-filled lung. Following the surgical procedure (day 1), serum amylase levels increased significantly (397 +/- 70-1,268 +/- 95 dye units) in group 2 but not in group 1. Alveolar epithelial permeability (expressed as T1/2 time in minutes to 50% equilibration between blood and lung liquid) did not increase in either group for dextrans or albumin. We conclude that experimental acute pancreatitis does not cause an increase in alveolar epithelial permeability for molecular weight substances up to 69,000 daltons.

Acute Disease↗
PubMed1980

A computerized diagnostic evaluation of a psychiatric problem.

The authors has developed a computerized system for diagnostic evaluation of a psychiatric problem on the Problem-Oriented Medical Information System (PROMIS). He evaluates the chief complaint of hyperactivity by the three-step process: 1) defining the problem, 2) considering causes that are common and easily reversible, and 3) considering other causes. Eleven physicians, including 6 psychiatrists, used this system. The psychiatrists thought the organization of the diagnostic evaluation was clinically sound and a useful training device. The nonpsychiatric physicians thought this diagnostic process was analogous to the diagnostic process for other medical problems.

Attention Deficit Disorder with Hyperactivity↗