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Biomedical subjects

N M Rich

Publications and source records attributed to N M Rich.

At least 55 records · Page 3Linked to original sources
PubMed1988

Long-term followup of penetrating abdominal aortic injuries after 15 years.

Eleven of 14 survivors who sustained trauma to the abdominal aorta have been evaluated 16 to 18 years after injury through personal interview, physical examination, and abdominal contrast computerized tomography (CCT). The average age of survivors was 39 years (range, 37-47). All patients had minimal debridement of the aortic injury with lateral arteriorrhaphy. No patients had symptoms of arterial insufficiency. However, five patients had abnormal ankle/brachial indices (ABI). In four patients, ABI was less than 1.00 at rest and a fifth patient's ABI decreased significantly: 0.60 left and 0.65 right from an average of 1.00 bilaterally after standardized exercise treadmill. CCT evaluation revealed aortic calcification in five patients in the area of aortic injury. Aortic calcification occurred only in the patients with abnormal ABI's. This long-term followup identifies no evidence for late compromise in the aorta; however, there is a suggestion that injury and repair may contribute to the accelerated development of atherosclerosis.

Adult↗
PubMed1988

Inhibition of acid secretion in guinea pigs by tricyclic antidepressants: comparison with ranitidine and omeprazole.

The antisecretory properties of imipramine on gastric secretion in guinea pig in comparison with other antisecretory agents was determined. In awake guinea pigs s.c. infusion of histamine (30 micrograms/kg/hr) increased acid and fluid secretion by 3- to 4-fold. When acid output peaked, a bolus administration of the tricyclic anti-depressant imipramine inhibited acid and fluid secretion. Imipramine and other agents, such as ranitidine and omeprazole, inhibited gastric secretion in a dose-dependent fashion. The most potent was the H2-antagonist ranitidine (IC50, 0.2-0.3 mumol/kg), followed by the gastric H-K-adenosine triphosphatase inhibitor, omeprazole (IC50, 0.5-0.6 mumol/kg). Imipramine (IC50 1-2 mumol/kg) was the least potent of the inhibitors. Both ranitidine and omeprazole could abolish acid secretion, but maximal inhibition with imipramine was 60% of initial. Promethazine (25 mumol/kg), an H1 antagonist, and atropine (12 mumol/kg), a muscarinic antagonist, inhibited gastric secretion by 40 to 50%. Imipramine and atropine also inhibited basal acid secretion. In dispersed gastric cells comparison between imipramine and omeprazole showed that imipramine was about 5-fold more potent than omeprazole in blocking histamine or dibutyryl cyclic AMP stimulation of aminopyrine accumulation. Imipramine probably acts as a protonophore by increasing the rate of proton-gradient dissipation rather than by interfering with the hydrogen-pump system because, in gastric membranes, imipramine was 20-fold less potent than omeprazole in inhibiting the gastric H-K-adenosine triphosphatase activity. These results suggest that imipramine administered s.c. in guinea pigs is a potent antisecretory drug. Its action may be due to a combination of anticholinergic and antihistamine H2 activities.

Adenosine Triphosphatases↗
PubMed1987

A new in vivo method for repeatedly studying gastric acid secretion and other secretory parameters in awake guinea pig.

A new model for measuring gastric secretory parameters in awake guinea pigs is described. A chronic cannula was surgically implanted in the stomach of each guinea pig. The rates of gastric secretion and changes in intragastric volume were measured using a dye dilution technique. In contrast to previous techniques in small laboratory animals, there was no collection of gastric juice via drainage, no oral intubation for aspiration was involved, no special or sophisticated equipment was used, no anesthesia was employed, and there was no stress associated with acute surgery. This method offers a valuable advantage by combining the chronic gastric cannula with a dye dilution technique in that the same animal can be used several times and finally, several gastric secretory parameters can be measured simultaneously. The animals were used from 3 weeks to 10 months after surgery and as many as 15 studies were performed on the same guinea pig. Samples were collected at 10-min intervals and analyzed for acid and dye concentration from which the onset and kinetics of gastric secretion were followed. Basal gastric secretion (11.8 +/- 1.6 mueq/kg/min; all mean +/- 1 SEM) was increased within 20 min after subcutaneous infusion of histamine (30 micrograms/kg/hr) and peaked by 40-60 min at a mean acid output rate of 41 +/- 3 mueq/kg/min. Histamine also increased the intragastric volume from 6.3 to 13.4 ml as it increased fluid output from 1.6 +/- 0.1 ml/10 min to 3.4 +/- 0.2 ml/10 min. The increase in acid output caused by histamine was inhibited by the H2-antagonists cimetidine (3 mumole/kg) and ranitidine at 0.5 mumole/kg. Omeprazole (1.2 mumole/kg), an H-K-ATPase inhibitor, almost abolished acid output under both basal and histamine-stimulated conditions. Thus, the present method is simple and suitable to study the physiology and pharmacology of gastric secretion in the guinea pig with a particular emphasis on the action of histamine. Furthermore, because of the species involved, there is also a significant economical advantage and the guinea pig can also be used as a potential model for studying experimental ulcer.

Animals↗
PubMed1986

Intraoperative local anesthetic injection of the carotid sinus nerve. A prospective, randomized study.

One hundred patients undergoing carotid endarterectomy under general anesthesia were prospectively randomized to receive either a local anesthetic injection of their carotid sinus nerve with bupivacaine (Marcaine) or no injection. Systolic blood pressure and pulse rate were recorded before injection and at 5 and 30 minutes after injection. The need for intraoperative and postoperative use of systemic vasopressor and vasodilator medications was recorded for each group as was the incidence of arrhythmias, neurologic complications, and myocardial infarctions. Intraoperative local anesthetic injection of the carotid sinus nerve did not significantly influence the intraoperative pulse rate or incidence of hypotension. It did, however, significantly increase the incidence of intraoperative hypertension and the need for systemic vasodilator medications intraoperatively. The incidence of postoperative hypotension (6 percent of patients), hypertension (34 percent), arrhythmias (6 percent), cerebrovascular accidents (1 percent), transient ischemic attacks (3.1 percent), and myocardial infarctions (2 percent) were not significantly influenced by intraoperative local anesthetic injection of the carotid sinus nerve. Intraoperative and postoperative hypotension did not cause morbidity in this series, however, local anesthetic injection was associated with a significant incidence of perioperative hypertension. Routine prophylactic local anesthetic injection of the carotid sinus nerve cannot be recommended in view of its detrimental effects in relation to the development of hypertension.

Anesthesia, Local↗
PubMed1986

The cytotoxic effect of surgical glove powder particles on adult human vascular endothelial cell cultures: implications for clinical uses of tissue culture techniques.

Clinical use of autogenous endothelial cell (EC) seeding of vascular prostheses (VP) would require reliable methods for EC harvest for immediate seeding or primary culture in a hospital or operating room setting. Observation of glove powder particles (GPP) in failed primary adult human saphenous vein EC (AHSVEC) cultures led us to study the effect of surgical GPP on cultured AHSVEC. Addition of GPP to the culture medium of growing ASHVEC cultures reduced the cell counts in a dose-dependent fashion; the mean concentration of GPP required to produce a greater than 50% decrease in cell number was 1.5 +/- 0.8 (SD) X 10(4) GPP/ml (N = 10 experiments), equivalent to a mean dose of 36 micrograms glove powder per milliliter. The effect was seen within 24 hr of addition of GPP and was not due to interference with EC attachment and spreading or to changes in medium osmolality, pH, glucose, electrolyte, Ca2+, or Mg2+ content. Instead, the effect appeared to be due to a filterable toxin added during the final rubber-vulcanizing stage of glove manufacture, since pure cornstarch particles and epichlorhydrin-treated pure cornstarch did not prevent culture growth, whereas 0.2 micron filtrates of medium incubated with GPP taken directly from gloves were lethal. We conclude that filterable cytotoxic substances from GPP may be an avoidable cause of failure in EC seeding of VP, and may affect surgical wound healing as well.

Cell Adhesion↗
PubMed1986

The noninvasive diagnosis of vasculogenic impotence.

One hundred eleven impotent men and 25 potent men were prospectively evaluated with a standardized exercise treadmill test (SETT) used to noninvasively define their pelvic hemodynamics. Fifty-six men had vasculogenic impotence, whereas the remaining 55 had erectile dysfunction resulting from undetermined causes (31), psychogenic factors (10), or other identifiable reasons (14). Arteriography was performed on 40 (71%) of the patients with vasculogenic impotence without false positive results, as well as in 11 (44%) of the potent control patients and in six (11%) of the patients with nonvasculogenic impotence without false negative results, confirming the validity of the SETT. The distinction between vasculogenic and nonvasculogenic impotence can be accurately made with the SETT. Patients with vasculogenic impotence had a resting penile-brachial index (PBI) equal to 0.60 +/- 0.022 (mean +/- SEM) and a PBI after exercise equal to 0.45 +/- 0.019 with a fall in the mean PBI of -0.15 (p less than 0.001). Patients with nonvasculogenic impotence had a resting PBI equal to 0.80 +/- 0.024 and a PBI after exercise equal to 0.88 +/- 0.019 with a rise in mean PBI of 0.08 (p less than 0.001). This response was not significantly different between the control group and the nonvasculogenic impotence patients. The addition of PBI determinations after treadmill exercise revealed that 18% of the patients with vasculogenic impotence would have been incorrectly diagnosed, because their resting PBI was greater than the traditional standard of 0.70. Furthermore, 18% of the patients with nonvasculogenic impotence would have been incorrectly diagnosed as having vasculogenic impotence because their resting PBI was less than 0.70.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1986

Effect of 1% sodium hyaluronate (Healon) on a nonregenerating (feline) corneal endothelium.

A series of experiments were performed to investigate the effect of 1% sodium hyaluronate (Healon) on the nonregenerating corneal endothelium of the cat. Aqueous humor replacement with 1% sodium hyaluronate resulted in mild, transient elevations of intraocular pressure compared to eyes that were injected with balanced salt solution. Sodium hyaluronate 1% protected the feline endothelium against cell loss incurred by contact with hyaluronate-coated intraocular lenses compared to endothelial contact with lenses that were not coated with sodium hyaluronate. The use of intraoperative 1% sodium hyaluronate, however, did not protect against endothelial cell loss incurred by penetrating keratoplasty or prevent subsequent skin graft-induced corneal homograft rejections. Homograft rejections were milder, however, in some eyes that received grafts coated with 1% sodium hyaluronate. Image analysis of photographs of trypan blue- and alizarin red-stained corneal buttons after trephining, stretching of Descemet's membrane, rubbing against iris-lens preparations, or immediately after penetrating keratoplasty demonstrated that the stretching of the posterior cornea is an important cause of endothelial damage that would not be protected against by a viscoelastic coating.

Animals↗
PubMed1986

Postnatal development of corneal endothelium.

Comparison specular micrographs of infant and adult corneas from cats, cows, dogs, rabbits, and humans demonstrate that a large decrease in central endothelial cell density occurs during maturation of the cornea. Central endothelial cell counts of developing cat, dog, and rabbit corneas decrease rapidly during the first months of life. This rapid decline in endothelial cell density correlates with growth of the cornea to the adult size. Central endothelial cell counts of adult cat, cow, deer, dog, pig, rabbit, and human corneas are similar (2500 cells/mm2) despite a wide variation in corneal size. Comparison of observed endothelial cell counts with two hypothetical situations, one of unrestricted endothelial mitosis and the other of only endothelial hypertrophy, indicates that hypertrophy of individual cells is primarily responsible for achieving the adult cell density of 2500 cells/mm2 for these species. This observation is true for species that have a high adult endothelial mitotic capacity (rabbit) as well as those that do not (cat). The human cornea is a special case because the decline in central endothelial cell density indicates that a large apparent corneal endothelial cell loss (approximately 45%) occurs early in postnatal development.

Adult↗
PubMed1985

Management of patients with symptomatic extracranial carotid artery disease and incidental intracranial berry aneurysm.

Perioperative fluctuation of blood pressure and the use of anticoagulants during carotid endarterectomy may potentiate lethal aneurysm rupture in patients who have symptomatic extracranial carotid artery occlusive disease with incidental, asymptomatic, intracranial berry aneurysms. Ten patients having this combination are described in the present study. Of five men and five women whose mean age was 63 years, nine had symptomatic carotid bifurcation atherosclerosis, one had internal carotid fibromuscular dysplasia, and all had intracranial berry aneurysms ranging from 2 to 13 mm in diameter (mean diameter 6.6 mm). In seven patients, aneurysms were greater than or equal to 6 mm in diameter. Hypertension was present in seven patients and moderately severe in five. Three of the aneurysms were located in the intracranial internal carotid artery, five in the middle cerebral artery, three in the posterior communicating artery, one in the anterior cerebral artery, and one in the superior cerebellar artery. Twelve carotid reconstructive procedures were performed without morbidity related to aneurysm rupture. These included 10 carotid endarterectomies, one of which was combined with Dacron patch angioplasty and one of which was combined with a simultaneous coronary artery bypass; one carotid artery dilatation for fibromuscular disease; and one reoperative carotid endarterectomy with patch angioplasty. Three patients had correction of hemodynamically significant lesions, two of which were proximal to ipsilateral anterior circulation aneurysms. An intraluminal shunt and heparin anticoagulation therapy were used in all patients. Despite a concerted effort to control blood pressure, the patients' perioperative blood pressures ranged from 60/30 to 240/110 mm Hg. Three patients had subsequent elective clipping of intracranial aneurysms.(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid Arteries↗
PubMed1985

Long-term patency of venous repairs demonstrated by venography.

Indications for venous reconstruction after traumatic injury are controversial, partly because of uncertainty of continued patency. We found no reports in the literature of truly long-term results after venous reconstruction. For clarification of this issue, we reviewed femoral venous injuries in a civilian metropolital population over a 20-year period. There were 31 patients with penetrating femoral venous injuries. Twenty-four patients underwent reconstruction. A search for these patients years after reconstruction located only five patients with six reconstructions. Followup venography at 6 to 20 years demonstrated venous patency and functional valves with asymptomatic patients and no clinical evidence of venous insufficiency in all cases excluding a single 1962 repair with a Teflon graft. This study then supports reconstruction rather than ligation after venous trauma. Although small, this series appears to be the only known report of truly long-term results following venous reconstruction.

Adult↗
PubMed1985

Saccular renal artery aneurysm as a cause of hypertension.

The case of a patient with renovascular hypertension related to an arterial kink is reported. The arterial kink was caused by a renal artery aneurysm and was not apparent with angiography. This is the first reported case in which renin-mediated hypertension was clearly related to a correctable mechanical problem from a saccular renal artery aneurysm. Indications for surgical repair of renal artery aneurysms and angiographic findings indicative of a functionally significant renal artery stenosis are reviewed.

Aneurysm↗
PubMed1985

Vascular malformations.

Fourteen patients with hemangiomas or arteriovenous malformations treated with operative management are described. Particular emphasis is placed on the definition of terms and the methods of differentiating arteriovenous fistulas, hemangiomas, and arteriovenous malformations. Arteriovenous fistulas are acquired lesions consisting of a single communication. Hemangiomas are congential lesions that rarely pulsate or have an associated bruit; moreover by angiography they have multiple small feeding arterial vessels and histologically are composed of numerous thin-walled, but normal-appearing, blood vessels. Arteriovenous malformations are also congenital but they pulsate and have associated bruits; furthermore on angiography they have a number of larger arterial feeding vessels and histologically are composed of abnormal dysplastic vessels. Operative management of all lesions should be carefully planned and executed. Arteriovenous malformations and skeletal muscle hemangiomas will have a tendency to recur if not completely excised.

Adolescent↗
PubMed1984

Focal motor seizures complicating carotid endarterectomy.

We studied four patients with focal motor seizures complicating carotid endarterectomy and compared them with 14 other cases reported previously. Seventeen of the 18 patients had high-grade carotid stenoses. A severe unilateral headache usually preceded seizure activity, which was followed by prolonged Todd's paralysis. Eight patients had histories of ipsilateral stroke. There was no association with perioperative hypertension. Two patients who were receiving heparin sodium had intracerebral hemorrhages that caused one of the two postoperative deaths. The patency of all endarterectomized carotid arteries was recorded by arteriography or noninvasive studies. These data suggest that patients who have severe unilateral headaches following ipsilateral carotid endarterectomy for high-grade stenoses are at risk for focal motor seizures. The roles of antithrombotic agents and anti-seizure medication in this setting are unclear.

Arterial Occlusive Diseases↗
PubMed1984

Adult human saphenous vein endothelial cells: assessment of their reproductive capacity for use in endothelial seeding of vascular prostheses.

Autogenous endothelial seeding (AES) of vascular prostheses (VP) using venous endothelial cells (EC) reduces platelet-VP interactions and improves patency rates in small caliber VP in dogs. To conserve patients' veins for use in coronary or limb bypass surgery, human trials of AES should require proof that adequate numbers of EC with the growth capacity to cover VP can be harvested from acceptably small pieces of peripheral vein. EC were isolated from excess saphenous vein segments remaining after coronary bypass surgery by filling veins with 0.1% CLS II collagenase at 37 degrees C for 15 min and removing EC by flushing the veins with culture medium. EC were cultured on fibronectin-coated dishes in medium 199 with 30% human serum and 300 micrograms/ml of endothelial cell growth factor. These cells grew to form confluent monolayers, and were identified as EC by tests for factor VIII antigen. Veins from 53 patients with a mean age of 55.8 +/- 9.8 (SD) years yielded vein segments with an average area of 1.9 +/- 0.6 cm2, from which an average of 5.3 +/- 2.8 X 10(4) cells were removed per cm2 of vein area. EC in culture underwent 14.3 +/- 1.4 population doublings with an average population doubling time of 1.8 +/- 0.3 days (N = 14 cultures), which allowed an 100-fold increase in cell number to occur in 11 to 12 days. These data suggest that the EC available from small vein segments in adult humans have the growth capacity to cover areas comparable in size to the luminal areas of VP commonly used in arterial surgery.

Adult↗
PubMed1984

Amputation risk factors in concomitant superficial femoral artery and vein injuries.

Only a small subset of patients with combined superficial femoral artery and vein injuries results in amputation. The importance of the venous component as a risk factor for amputation is uncertain. Ligation vs. reconstruction of venous injuries is controversial. For clarification of these issues, we analyzed retrospectively multiple risk factors for amputation in combined superficial femoral artery and vein injuries in a civilian population. There were 25 patients treated in a 20-year period. Sixteen injuries were caused by small caliber missiles, six by shotgun blasts, and three by knife wounds. Three patients (12%) ultimately underwent amputation. The major risk factor for amputation was method of vascular reconstruction. All three amputations underwent ligation of the superficial femoral vein with arterial reconstruction by placement of a reversed interposition saphenous vein graft (p = 0.0009). None of the remaining 22 patients with salvaged limbs underwent reconstruction by this combination of techniques. Consequently, the authors emphasize the importance of venous reconstruction, particularly in combined injuries with major arterial involvement requiring interposed grafts.

Adolescent↗
PubMed1984

Thromboembolectomy of arteries explored at the ankle.

Experience with 11 cases of thromboembolectomy of leg arteries explored at the ankle is presented. Patency was established in 19 of 23 arteries (83%), resulting in salvage of 11 of 14 limbs (79%). This experience documents success of this technique with follow-up ranging from 2 to 70 months (mean followup, 24.7 months). Current indications for the procedure include 1) incomplete extraction of thrombus via the popliteal trifurcation, 2) incomplete transfemoral extraction of thrombus with restoration of a popliteal pulse, and 3) thromboembolus initially confined to the infrapopliteal arteries.

Adult↗
PubMed1984

Femoral anastomotic false aneurysms. An 11-year experience analyzed with a case control study.

Eighty-three femoral anastomotic false aneurysms occurring in 51 patients were diagnosed from 1972 through 1982. Twenty-two (27%) presented with acute events. Seventy (84%) were confirmed by sonography and/or arteriography. Bilaterality (29%), recurrence (18%), and associated aortic false aneurysms (8%) were significant problems. Eight-one were repaired with a six per cent complication rate, including one death related to preoperative rupture. The 51 patients were evaluated for associated illnesses, risk factors, and etiologies of their false aneurysms. The most common single cause (61%) was host vessel degeneration with an intact suture line remaining attached to a disrupted Dacron limb. Twenty-three patients with host vessel degeneration were matched with case controls not developing false aneurysms. These two groups were matched for gender, age, and year of AFB and compared for associated illnesses and risk factors. Incidences of cigarette smoking, hypertension, cerebrovascular disease, coronary artery disease, diabetes mellitus, previous femoral endarterectomy, outflow disease, other aneurysmal disease, multiple groin operations, wound complications, and training levels of surgeons performing initial AFBs were similar for both groups. Factors observed significantly more often in patients who developed false aneurysms included serum lipid abnormalities (p less than 0.05), braided synthetic suture material as opposed to monofilament polypropylene (p less than 0.05), and continued abuse of tobacco following AFB (p less than 0.005).

Aged↗