Extension of limb salvage by combined vascular reconstruction and adjunctive free-tissue transfer

PURPOSE

Vascular reconstruction alone can be insufficient for extremity salvage in some patients with severe soft-tissue wounds. We present our experience in 20 patients with vascular reconstruction for ischemic disease and free-tissue transfer for limb-threatening soft-tissue wounds.

METHODS

Nineteen patients underwent autogenous venous bypasses and one patient underwent an aortobifemoral bypass. Ten soft-tissue reconstruction were performed at the time of the vascular reconstruction and 10 were delayed. Free-tissue transferred included muscle, fasciocutaneous flaps, and omentum. Inflow to the flap was from the bypass graft (n = 12) or the distal tibial artery.

RESULTS

One free flap and graft failed immediately in the same patient. One successful flap and graft required a below-knee amputation for ongoing infection in the surrounding soft tissues. Eighteen of 20 patients have had free-flap and graft patency during the mean follow-up period of 17 months (range 6 to 33 months). These 18 patients ambulate independently.

CONCLUSIONS

In patients with arterial insufficiency and severe soft-tissue wounds, combined vascular reconstruction and free-tissue transfer permits extended limb salvage with excellent functional results.

Concentrations of doxorubicin and its metabolites in human autopsy heart and other tissues

PURPOSE

Since doxorubicin causes cardiotoxicity, we wished to assess relative concentrations of doxorubicin and its metabolites in cardiac tissues of patients who had been treated antemortem. We also wished to determine factors that correlate with human cardiac doxorubicin and doxorubicinol concentrations.

PATIENTS AND METHODS

Autopsy tissues were collected from 35 patients who had received doxorubicin at any time antemortem, and were assayed by high pressure liquid chromatography.

RESULTS

The major species found in human autopsy cardiac tissues were doxorubicinol (median concentration 92 ng/g, range 0 to 484 ng/g), and doxorubicin (median 58 ng/g, range 0-1665 ng/g). Other doxorubicin metabolites were detected in cardiac tissues in < half the patients. Of ten organs studied, heart ranked fifth with respect to median doxorubicin concentration and ranked fourth with respect to median doxorubicinol concentration. By multiple stepwise regression analysis, factors most closely associated with cardiac doxorubicin concentrations were time from last treatment divided by dose intensity, serum total protein, albumin, and hemoglobin (negative correlations). Factors most closely associated with cardiac doxorubicinol concentrations were cumulative doxorubicin dose, total protein, hemoglobin, and uric acid (positive associations), and respiratory rate (negative association). The physiologic significance of these associations (if any) is uncertain. By paired t-tests, cardiac doxorubicin and doxorubicinol concentrations were significantly (p < 0.05) higher than concentrations in skeletal muscle and smooth muscle organs.

CONCLUSIONS

Overall, the results suggest that the much greater tendency to develop doxorubicin toxicity in heart than in other types of muscle may be due to a propensity of cardiac muscle to accumulate doxorubicin. The results also suggest that doxorubicinol may play a role in doxorubicin cardiac toxicity, and that doxorubicin may be gradually converted to doxorubicinol in human tissues.

The method of public morality versus the method of principlism

Two years ago in two articles in a thematic issue of this journal the three of us engaged in a critique of principlism. In a subsequent issue, B. Andrew Lustig defended aspects of principlism we had criticized and argued against our own account of morality. Our reply to Lustig's critique is also in two parts, corresponding with his own. Our first part shows how Lustig's criticisms are seriously misdirected. Our second and philosophically more important part picks up on Lustig's challenge to us to show that our account of mortality is more adequate than principlism. In particular we show that recognition of mortality as public and systematic enables us to provide a far better description of morality than does principlism. This explains why we adopt the label "Dartmouth Descriptivism."

Predictive value of dobutamine echocardiography just before noncardiac vascular surgery

This study prospectively evaluated 75 consecutive patients (mean age 69 +/- 9 years) undergoing major vascular surgery to test the hypothesis that dobutamine stress echocardiography can be used to predict perioperative cardiac events. A positive test was defined as a new or worsening wall motion abnormality in at least 2 of 18 wall segments. Up to 40 micrograms/kg/min of dobutamine was administered. All readings were done by physicians unaware of the patients' symptoms and electrocardiographic response. In addition, physicians caring for the patients were unaware of the test result. End points of the study were unstable angina with documented electrocardiographic changes, nonfatal myocardial infarction or cardiac death. The perioperative ischemic event rate was 7% (5 of 75 patients). Three patients developed unstable angina and 2 sustained nonfatal myocardial infarctions. All of these patients had positive results on dobutamine stress echocardiography (sensitivity 100%). However, 22 patients who also had positive results on dobutamine stress echocardiography did not have perioperative events (specificity 69%). The corresponding positive predictive value was 19%. None of the 48 patients who had negative results on dobutamine stress echocardiography had events (negative predictive value 100%). In conclusion, dobutamine stress echocardiography can be used to predict perioperative events with great sensitivity, but its positive predictive value in this patient population in low, likely due to the low incidence of perioperative events in patients with known coronary artery disease and the imperfect specificity of dobutamine stress echocardiography in identifying significant coronary stenosis. Dobutamine stress echocardiography is most useful in this setting when negative, because it predicts safety from complications with confidence.

Transfemoral endovascular aortic graft placement

PURPOSE

The purpose of this study was to develop an endovascular system for transfemoral placement of straight aortic grafts and bifurcated aortoiliac grafts.

METHODS

Both types of graft consist of barbed, self-expanding stents attached to a woven polyester fabric. Survival studies of straight-graft function were performed in six large mongrel dogs. Digital subtraction fluoroscopic equipment was used to guide insertion and record angiograms at 0, 1, and 3 months. Bifurcated grafts were inserted in an additional eight dogs, four with distal stents and four without. Straight grafts were inserted into six cadaveric aortas (five atherosclerotic and one aneurysmal; age 68.7 + 5.7 years) to assess stent attachment.

RESULTS

Angiograms obtained immediately after straight-graft insertion showed placement to be within 4.6 + 1.6 mm of the intended level. Follow-up angiograms at 1 and 3 months showed no migration, no leakage, and patency of all six grafts. After bifurcated graft insertion there were no angiographic signs of perigraft leakage, with or without distal stents. The mean force required to displace straight grafts 10 mm from their original position in cadaveric aortas was 1388 + 127 g.

CONCLUSION

These preliminary results show that straight and bifurcated endovascular grafts can be positioned accurately and securely in the abdominal aorta.

Intraoperative autotransfusion in aortic surgery

PURPOSE

Intraoperative autotransfusion is frequently used in aortic surgery, despite the paucity of data regarding its safety and efficacy. This study was designed to compare whole blood autotransfusion with homologous transfusion for the replacement of blood lost during abdominal aortic procedures.

METHODS

Whole blood autotransfusion was evaluated in 200 patients undergoing aortic reconstructive procedures during a 3-year period. Collection and reinfusion of unwashed filtered shed blood was undertaken in 100 patients, and clinical, laboratory, and economic parameters were compared with those in a group of 100 patients undergoing aortic operation with homologous banked blood replacement.

RESULTS

The two groups were comparable with respect to demography, the type of procedure, baseline laboratory profile, and the frequency of coexistent medical illnesses. The amount of blood salvaged and reinfused averaged 1729 +/- 68 ml in the autotransfusion group. Patients undergoing autotransfusion received a mean of 0.6 +/- 0.1 units of banked blood during operation, compared with 3.4 +/- 0.1 units in the homologous group (p < 0.001). Operative morbidity and mortality rates were comparable between the groups, as were length of hospital stay and total hospital costs. Coagulopathy, renal insufficiency, abnormalities of oxygen exchange, and electrolyte disorders were infrequent. Autotransfusion offered significant advantages over homologous blood replacement with respect to improved preservation of circulating platelets (201 +/- 9 vs 157 +/- 6 x 10(3)mm3, p < 0.001) and coagulation factors (242 +/- 11 vs 196 +/- 14 mg fibrinogen/dl, p < 0.01) and limitation of exposure to homologous blood (34% vs 92%, p < 0.001). There was a significant cost advantage with the use of autotransfusion, with an average savings of $288 in hospital expenses associated with blood products and infusion equipment. Patients undergoing autotransfusion demonstrated aberrations in fibrin degradation products (33 +/- 4.4 vs 9.6 +/- 3.2 micrograms/ml, p < 0.001) and free plasma hemoglobin (29 +/- 9.1 vs 9.4 +/- 0.5 mg/dl, p < 0.05), but these laboratory abnormalities did not acquire clinical significance.

CONCLUSION

These data suggest that autotransfusion of unwashed, filtered blood is a safe and efficacious alternative to homologous blood replacement in patients undergoing major aortic reconstructive procedures.

Human autopsy-tissue distribution of menogaril and its metabolites

Autopsy-tissues were obtained from eight patients who had last received menogaril (total cumulative dose, 175-1080 mg/m2) intravenously (one patient) or orally (seven patients) from 1 to 285 days prior to death. Tissue samples were assayed for menogaril and its metabolities by high-pressure liquid chromatography. Unchanged menogaril was found only in a single lung-tissue sample from a patient who had died < 24 h after receiving his last treatment. N-Demethylmenogaril was found in two lung-tissue samples and in single samples of the thyroid, lymph node, pancreas, cerebellum, and tumor. The major menogaril metabolite found in human autopsy-tissues was 7-deoxynogarol. The highest 7-deoxynogarol concentrations were found in the large bowel (median, 201 ng/g), liver (median, 183 ng/g), and lung (median, 177 ng/g). The heart ranked as the 9th of 18 organs in median 7-deoxynogarol concentration, after the large bowel, liver, lung, tumor, thyroid, skeletal muscle, adrenal gland, and kidney. The lowest concentrations were detected in brain tissue. Our results suggest that the low degree of cardiac toxicity and the possible pulmonary toxicity of menogaril may be related to relative tissue concentrations of menogaril metabolites. Tumor 7-deoxynogarol concentrations were comparable with those in normal tissues, except that concentrations in intracerebral tumors were higher than those in the normal brain. Tissue 7-deoxynogarol concentrations appeared to be directly related to the cumulative dose and inversely related to the time from the last treatment to death; the value obtained by dividing dose by time correlated (P < 0.05) with tissue 7-deoxynogarol concentrations.

Human autopsy tissue distribution of the epipodophyllotoxins etoposide and teniposide

Autopsy tissues were collected from ten patients who had received etoposide, 150-3480 mg, from 1 to 412 days antemortem and from five patients who had received teniposide, 234-1577 mg, from 3 to 52 days antemortem. Tissues were assayed for etoposide and teniposide using high-pressure liquid chromatography with electrochemical detection. Etoposide was detectable in tissues of three of four patients dying < 5 days after their last etoposide treatments to cumulative doses of 150-432 (median, 280) mg but was detectable in tissues of only one of six patients dying 7-412 (median, 37) days after their last etoposide treatment to a cumulative dose of 607-3600 (median, 1553) mg. The highest tissue concentrations were in the small bowel, prostate, thyroid, bladder, spleen, and testicle. Intermediate concentrations were found in the lymph node, skeletal muscle, adrenal gland, stomach, tumor, liver, lung, pancreas, and kidney, and the lowest concentrations were found in the heart, brain, diaphragm, vagina, and esophagus. Teniposide was detectable in one patient dying 3 days after a cumulative teniposide dose of 576 mg (spleen, prostate, heart > large bowel, liver, pancreas > thyroid, adrenal, stomach, small bowel, bladder, testicle, and skeletal muscle) but was not detectable in any tissue from four patients dying 5-52 (median, 8) days after their last treatment to a cumulative teniposide dose of 234-1577 (median, 520) mg. The very short tissue half-life contrasts with our previous observations for human autopsy tissue concentrations of mitoxantrone, doxorubicin, menogaril metabolites, diaziquone, and amsacrine. The short tissue half-life may help explain the schedule dependency of epipodophyllotoxin efficacy and may also help explain the lack of visceral toxicity of these compounds.

Neurologic events following carotid endarterectomy: prediction of outcome

A total of 1572 carotid endarterectomies were performed at one institution between 1975 and 1987. One hundred five patients had early (< 3 weeks) neurologic events following carotid endarterectomy. Sixty-five patients had cerebral vascular accidents (CVAs) (4.1%), 14 patients had reversible ischemic neurologic deficits (0.9%), and 26 patients had transient ischemic attacks (1.7%). Eight patients died from CVAs (0.5%). The mean follow-up was 31 months (range 1 to 137 months) with a 5-year cumulative survival of 77%. The median time of occurrence of neurologic events was 4 hours. Ages, cerebral protection, patches, carotid occlusion time (mean 29 minutes), gender, and status of the contralateral carotid arteries were not predictors of outcome. Death from neurologic events increased significantly in patients who had preoperative CVAs compared with patients with preoperative transient neurologic deficits (p < 0.05). The time of occurrence of CVA after carotid endarterectomy affected outcome, and an early CVA (< 4 hours) was associated with a higher mortality at 30 days and at 4 months as a consequence of the initial CVA (p = 0.11). Patients who had a neurologic event more than 4 hours after surgery had a significantly better resolution of their symptoms (66%) compared with patients who had an early neurologic event (35%, p < 0.05). The long-term follow-up of the surviving patients demonstrated an improvement in neurologic function in 75% of the CVA group (36/48) and 92% (76/83) of all patients who had neurologic events in long-term follow-up.

Pulmonary embolism in younger adults

To test the hypothesis that the clinical presentation and outcomes are different when pulmonary embolism occurs in younger (age 18 to 40 years) as compared to older (age greater than 40 years) adults, 40 younger patients were compared with older patients. No risk factors could be identified in 28 percent of the younger group. Normal physical examinations were more common (58 vs 28 percent, p = 0.01) among younger as compared with older adults. Hypoxemia was absent in 29 percent of the younger and 3 percent of the older group (p = 0.004); P(A-a)O2 was significantly lower among younger patients even after controlling for age. Mortality was decreased sevenfold (2.5 vs 18 percent, p = 0.03) among younger patients. These data indicate that pulmonary embolism tends to have a subtle presentation in younger adults. When diagnosed and treated, the mortality rate is substantially less among younger as compared with older patients.

Bacteremia after endoscopic band ligation of esophageal varices

In a 6-month period, 17 consecutive unselected patients undergoing emergency or elective endoscopic variceal band ligation were evaluated prospectively for clinical and bacteriological signs of bacteremia after each treatment session. None had signs of sepsis, fever, or chills; however, in one patient, a coagulase-negative Staphylococcus epidermidis was cultured from peripheral blood at 5 but not 30 min after the procedure. These data indicate that, in contrast to sclerotherapy, endoscopic variceal ligation rarely induces bacteremia.

Kinetics of open channel block by penicillin of single GABAA receptor channels from mouse spinal cord neurones in culture

1. Reduction by penicillin of single gamma-aminobutyric acidA (GABAA) receptor currents from somata of mouse spinal cord neurones in culture was investigated using the excised outside-out patch-clamp recording technique. 2. GABA (2 microM) alone or with penicillin (100-5000 microM) applied by pressure ejection from micropipettes evoked inward currents when patches were voltage-clamped at -75 mV in symmetrical chloride solutions. Averaged GABA receptor currents were decreased in the presence of penicillin. 3. GABA receptor currents were recorded with at least two conductance states, a more frequent or main-conductance state of about 27 pS and a less frequent sub-conductance state of about 19-20 pS. The conductances of the two states were unchanged in the presence of penicillin. The kinetic properties of the main-conductance state were analysed and are summarized below. 4. Penicillin produced a concentration-dependent reduction of GABA receptor open properties by reduction of average GABA receptor channel open duration and an increase in channel opening frequency. 5. Penicillin shifted frequency histograms of GABA receptor channel open durations to shorter durations in a concentration-dependent manner. Three exponential functions were required to fit best the frequency histograms of open durations, suggesting that the channel had at least three open states. Penicillin produced a concentration-dependent reduction in the time constants obtained from the open duration frequency histograms. 6. Frequency histograms of GABA receptor channel closed durations could be fitted with five to seven exponential functions, suggesting that the channel had multiple closed states. In the presence of increased concentration of penicillin, there was a reduction in the relative frequency of brief gaps and the appearance of new closed time constants. 7. With increased penicillin concentration, GABA receptor channel burst frequency was unchanged, burst durations were increased, the number of openings per burst was increased and the per cent time open within a burst was decreased. 8. The results suggested that penicillin produced simple open channel blockade of the GABA receptor channel. However, the experimental results also suggested that the association with and, perhaps, the dissociation of the blocker from its binding site were dependent upon the kinetic state of the open channel. Penicillin had faster association and slower dissociation rates when the channel was in unstable, brief open kinetic state than when the channel was in a more stable, longer open kinetic state. Possible models for penicillin reduction of single GABA receptor currents were simulated by computer and analysed.(ABSTRACT TRUNCATED AT 400 WORDS)

Vascular disease in the antiphospholipid syndrome: a comparison with the patient population with atherosclerosis

The antiphospholipid syndrome was diagnosed in 19 of 1078 patients treated between 1987 and 1991. All patients with antiphospholipid syndrome had either anticardiolipin antibody (16/19) or lupus anticoagulant (10/19); three patients had thrombocytopenia, eight patients had a prolonged partial thromboplastin time, and 10 patients had an elevated erythrocyte sedimentation rate. The most common site of involvement was the cerebral circulation (nine patients), manifested by transient ischemic attacks or stroke. Eight patients had upper extremity disease, characterized by symptoms of Raynaud's phenomenon, with angiographic lesions involving the brachial, radial, ulnar, and/or digital arteries. Lower extremity disease occurred in seven patients, with clinical presentations similar to those of atherosclerosis and varying angiographic patterns. In comparison with the population having atherosclerosis, patients with arterial manifestations of antiphospholipid syndrome were more likely to be women (13 of 19 versus 411 of 1078, p less than 0.02), were significantly younger (46.2 years versus 63.6 years, p less than 0.0001), did not smoke (1 of 19 patients versus 700 of 1078, p less than 0.0001), had a higher percentage of upper extremity involvement (8 of 18 versus 13 of 1078, p less than 0.0001), and had a higher incidence of early graft failure (9 of 12 grafts versus 13 of 371 grafts, p less than 0.0001). The syndrome is associated with the repetitive failure of vascular reconstructions and occlusion of native vessels. Antiphospholipid syndrome should therefore be suspected in young, female, nonsmokers with vascular disease, especially those with involvement of the upper extremity, cerebrovascular disease with normal findings on extracranial carotid angiography, and premature graft failure.

An evaluation of new methods of expressing aortic aneurysm size: relationship to rupture

The diameter of aortic aneurysms were standardized to measures of patient size and normal aortic size in an effort to define indexes that might be more predictive of aneurysm rupture than raw aneurysm diameter alone. Normal aortic diameters were measured in 100 patients undergoing abdominal CT scans for other reasons, and an average infrarenal aortic diameter of 2.10 +/- 0.05 cm was observed. Normal aortic diameter was dependent on both age and sex, ranging from 1.71 +/- 0.06 cm in women below age 40 years to 2.85 +/- 0.04 cm in men above age 70 years. Overall, 11 (5.1%) of the ruptures occurred in aneurysms less than 5 cm in diameter, and four (1.9%) occurred in aneurysms less than 4.0 cm in diameter. When the CT scans of 100 patients undergoing elective aneurysm resection were compared with those of 36 patients with ruptured aneurysms, no threshold diameter value accurately discriminated between the two groups. However, standardization of the aneurysm diameter to the transverse diameter of the third lumbar vertebral body as an index of patient body size produced an accurate predictor of rupture when a threshold ratio of 1.0 was used. No aneurysm ruptured below this ratio, but 29% of elective aneurysms were smaller than the vertebral body diameter. Receiver operating characteristic curve analysis confirmed the superiority of the aneurysm to vertebral body diameter ratio as a discriminator of ruptured aneurysms. It appears that aneurysm diameter alone is not sufficiently predictive of rupture to be used as the sole indication for elective resection.

Peroneal artery bypass: a multifactorial analysis

Sixty-two bypass grafts to the peroneal artery were performed at the University of Rochester Medical Center between 1984 and 1990. An autogenous conduit was used in 45 patients and a prosthetic conduit in 17 patients. Primary cumulative patency rates were 49% at two years and 30% at four years following operation. Limb salvage was achieved in 68% of patients. The two year cumulative patency rate was significantly better when the peroneal artery was of good quality arteriographically compared with those in which stenoses were present (75% versus 25%, p less than 0.05); in patients without inflow disease compared with patients with inflow disease (56% versus 11%, p less than 0.05); and in saphenous vein grafts compared with prosthetic grafts (55% versus 17%, p less than 0.05). The factors that did not influence patency were the presence of a direct peroneal collateral vessel filling a pedal vessel, age, sex, diabetes, and the size of the peroneal artery. The results of peroneal artery bypass in end-stage patients are dependent on the presence of adequate autogenous vein and a recipient peroneal vessel free of disease. Under these circumstances, the results of the procedure approach that of standard femorotibial reconstruction.

Amyloidosis in association with human immunodeficiency virus infection

Amyloidosis has not been previously reported in association with human immunodeficiency virus (HIV) infection. An HIV-infected patient with hemophilia who developed nephrotic syndrome due to amyloidosis is described. Amyloid disease has been observed in monkeys with AIDS, and patients with AIDS have had elevated levels of amyloid A protein, findings that suggest a pathogenetic linkage between the two disorders. Amyloidosis should be considered in the differential diagnosis of HIV-associated nephropathy and the nephrotic syndrome in HIV-infected patients.

Long-term follow-up after thoracic outlet decompression: an analysis of factors determining outcome

We reviewed our 12-year experience with transaxillary first rib resection in 136 patients screened by neurologists and thought to have neurologic thoracic outlet syndrome to determine what factors affected outcome. These patients represented 85% of the operative experience in a referral area of 1.2 million people. Patients were recalled every 2 years for surveillance. The mean follow-up was 60 +/- 7 months. There were no brachial plexus or vascular injuries. Secondary operations in the neck were required in 20 patients. The quality of the operative result was determined by whether the patient was able to return to preillness activities and whether the patient would undergo operation again if the same result would be obtained. The most important determinant of result was a history of trauma precipitating the neurologic symptoms, particularly in women. Only 25 of the 53 patients (47%) with a history of trauma returned to preillness activities compared to 65 of the 83 patients (78%) without such a history. Overall patient satisfaction was not affected by trauma. Thirty-eight of the 53 patients with trauma (72%) and 69 of the 83 patients (83%) without trauma were satisfied. When the men and women were analyzed separately men were found to have better results after trauma than did women. Other factors with a negative impact on operative results were the need to return to an activity that required repetitive arm movements, coverage under a worker's compensation insurance policy, and fixed joint abnormalities or neurologic findings in the upper extremity. The presence of an anatomic abnormality had no effect on operative results.(ABSTRACT TRUNCATED AT 250 WORDS)

Popliteal artery aneurysms: a 25-year surgical experience

Operative repair was undertaken for 51 popliteal aneurysms in 39 patients between 1958 and 1990. Operation was performed on an emergency basis in 19 extremities with limb-threatening ischemia and as an elective procedure in 32 extremities. Cumulative limb salvage (94%) rates and patency rates (67%) became significantly different at 6 years (p less than 0.05). Graft patency was affected by clinical presentation and runoff. After 1 year, cumulative patency for extremities with limb-threatening ischemia was significantly lower than for those having an elective operation (69% vs 100%, p less than 0.05). Runoff did not influence graft patency until 3 years, at which time cumulative patency was better in extremities with good runoff than in extremities with poor runoff (89% vs 30%, p less than 0.05). Limb salvage was affected only by presentation. All limb loss (three patients) occurred within the first month in extremities with graft occlusion after operation for limb-threatening ischemia. Runoff did not influence patency rates for extremities with limb-threatening ischemia, since no difference was observed in runoff between the two groups. We conclude that elective repair is indicated in all patients with popliteal aneurysms. It is associated with little risk to the patient, and prevents the need for operation in the setting of limb-threatening ischemia with its poorer overall results and definite incidence of amputation.

The hemodynamics of thrombus formation in arteries

Alterations in arterial blood flow are thought to predispose to thrombus formation, but the exact relationships have not been fully elucidated. The effect of varying blood flows on the accumulation of thrombotic material within arteries was investigated, with use of shear rate as an index of flow across the luminal surface. Partially denuded rabbit aortas were perfused with fresh nonanticoagulated human blood for 3 minutes, with an in vitro recirculating apparatus, Indium 111-labeled platelets, and fibrinogen I 125. Shear rates ranged from zero to 1500 sec-1, correlating with the hemodynamics of various segments of the human arterial tree. A significant correlation was observed between shear rate and platelet deposition, ranging from 5.2 +/- 2.8 x 10(6) platelets/cm2 of vessel surface area at zero shear to a maximum of 64.7 +/- 8.3 x 10(6) platelets/cm2 at a shear rate of 1500 sec-1 (F = 5.01, p less than 0.05). Fibrin deposition paralleled that of platelets, ranging from 28.2 +/- 7.6 micrograms/cm2 at zero shear to 354.1 +/- 62.7 micrograms/cm2 at a shear rate of 1500 sec-1 (F = 5.91, p less than 0.05). These results suggest that shear rate is a most important determinant of platelet and fibrin deposition on altered arterial surfaces.

Suppurative cervical lymphadenitis after Yersinia enterocolitica bacteremia

Yersinia enterocolitica is increasingly recognized as a pathogen causing diverse complications. We have reported the case of a man with fever, abdominal tenderness, and Y enterocolitica bacteremia. After antibiotic therapy, his condition improved initially, but later, suppurative cervical lymphadenitis developed. This suggests that the hematogenous spread of Y enterocolitica to a distal lymphatic focus of infection is a possible complication of Y enterocolitica bacteremia.

Laser angioplasty in peripheral vascular disease: symptomatic versus hemodynamic results

Most early reports on the efficacy of laser angioplasty have used subjective symptoms rather than objective hemodynamic parameters to evaluate clinical results. We reviewed our experience with hot tip laser-assisted balloon angioplasty in 99 occluded or stenotic arterial segments during 80 procedures in 71 patients, ranging from the aortic bifurcation to the tibial-peroneal trunk. Initial failure to successfully recanalize occluded or stenotic segments occurred in 13 instances (16%). Forty-one procedure-related complications occurred in 31 patients (39%). Functional results were evaluated by use of life-table methods on the basis of symptomatic versus hemodynamic improvement. Cumulative patency rates for symptomatic and hemodynamic improvement were 91% and 64% at 1 month, 71% and 48% at 6 months, and 57% and 34% at 1 year, respectively. These data suggest that symptomatic improvement alone gives a misleadingly high estimate of the efficacy of laser angioplasty when compared with more objective hemodynamic criteria (p less than 0.005). Hemodynamic success was more likely in aortoiliac lesions than femoropopliteal lesions (58% vs 18% at 1 year, p less than 0.01). Hemodynamic parameters should be used to evaluate the success of laser angioplasty, which in its present form, is associated with frequent complications and poor long-term success.

Bioavailability and pharmacology of oral idarubicin

A total of 9 patients entered in a phase I trial who received oral idarubicin daily for 3 days took part in pharmacokinetic studies, and bioavailability studies were performed on 13 additional patients receiving single doses of oral idarubicin alternating with i.v. treatment. The data were best fit by a two-compartment model (distribution and elimination compartments for i.v. drug and absorption and single-phase elimination for oral drug). For different idarubicin doses in the phase I and bioavailability studies, the median values for the terminal half-life of idarubicin varied from 5.6 to 11.6 h. High concentrations of the active metabolite idarubicinol were formed. Idarubicinol was eliminated more slowly than was the parent compound, with median half-lives for different dose levels varying from 8 to 32.7 h. Although most pharmacokinetic parameters were similar in plasma and whole blood, peak concentrations and AUCs in whole blood were about 3-4 times those calculated in plasma for idarubicin and about 1.5-2 times those determined in plasma for idarubicinol, indicating fairly extensive uptake into erythrocytes. Oral bioavailability was determined by comparing oral idarubicin to i.v. drug with respect to the combined idarubicin and idarubicinol plasma AUCs, and it varied from 12%-49% (median, 29%). Bioavailability was essentially the same (30%) when whole-blood values were used. Urinary excretion of the drug was less than 5% of the delivered dose by 96 h. Granulocytopenia correlated with plasma idarubicinol "estimated" clearance and steady-state volume of distribution, with whole-blood idarubicinol AUC, area under the moment curve (AuMC), and "estimated" clearance and volume of distribution, and with whole-blood combined idarubicin and idarubicinol AUCs. This suggests that drug contained in erythrocytes plays a major role in toxicity and that idarubicinol may play a larger role in toxicity than does the parent compound.

An examination of strains of the bacterium Streptococcus vestibularis for relative cariogenicity in gnotobiotic rats and adhesion in vitro

The cariogenicity and adhesion of six strains of Streptococcus vestibularis were compared with those of strains of Strep. salivarius. All strains of Strep. vestibularis produced low levels of caries, confined to the fissures, whereas the two strains of Strep. salivarius produced high levels of caries, with one strain producing approximal as well as fissure caries. The values for adhesion to saliva-coated hydroxyapatite of Strep. vestibularis in the absence (median 4.74%) and the presence (median 4.67%) of sucrose were not statistically different, nor did they differ significantly from those of Strep. salivarius. Strains of Strep. vestibularis were able to adhere to buccal epithelial cells (median 1.19%) as well as could Strep. salivarius strain HB (1.65%). Neither sucrose nor saliva greatly aggregated the strains of either species. Strep. vestibularis did not adhere to hexadecane (median 18.5%) to the same extent as did Strep. salivarius strains (median 69%). There was a significant correlation between the adhesion in the presence and absence of sucrose (p less than 0.01). Strep. vestibularis strains could not coaggregate with either actinomycetes or Veillonella spp. whereas Strep. salivarius strains were able to coaggregate with Veillonella spp.

The clinical course of residual carotid arterial disease

Over a 5-year period 642 patients underwent 686 carotid endarterectomies with patch closure and intraoperative surveillance with continuous-wave Doppler. The perioperative stroke rate was 1.5%. Patients were screened with duplex scans immediately after operation for the presence of residual carotid lesions, and followed every 3 to 6 months for either the development of a true recurrent lesion or a change in a residual one. Five hundred thirty-nine arteries (84%) had no postoperative abnormalities. The incidence of recurrent carotid lesions in this groups was 1.5%, 3.4%, and 5.2% at 1, 2, and 3 years, respectively. The incidence of symptoms in this group was 0.2%, 0.7%, and 1.4% at 1, 2, and 3 years, respectively. The earliest recurrence or symptom occurred 8 months from operation. One hundred forty-seven arteries had residual lesions that were more common when either a temporary shunt was used or the operation was carried out above the hypoglossal nerve or below the omohyoid muscle. Sixty-one patients who had plaque proximal to the arteriotomy without a significant stenosis were followed an average of 21 months. There were no changes in plaque morphology and no proven symptoms related to the residual lesion. Fifty-six patients with both plaque and significant hemodynamic abnormalities in the carotid bulb were followed an average of 18 months. Seven of these patients (12.5%) had either a significant deterioration of the lesion or a symptom from it. Each event occurred within 6 months of operation. Thirty patients had significant flow abnormalities but no visible plaque. None of these lesions deteriorated. Although common, residual carotid lesions are benign unless the lesion is characterized by both plaque within the artery and a hemodynamically significant stenosis. These lesions should be further investigated and treated when discovered.

Fate of the exposed saphenous vein graft

Patients with functioning vein grafts may present with wound problems resulting in exposure of the graft. We reviewed the courses of 16 patients presenting with this problem to determine the causative factors and the most appropriate management of this therapeutic dilemma. Diabetes mellitus (11 of 16, 68.7%) and wound infection (12 of 16, 75%) were frequent pre-existing conditions associated with exposed venous grafts. All patients with exposed vein grafts were initially treated conservatively with regular application of moist sterile dressings, followed by split-thickness skin graft coverage of the wounds when clean. The wounds healed in 7 patients, whereas 9 patients developed complications of hemorrhage (7 patients) and graft thrombosis (2 patients). The outcome of therapy was highly dependent on the type of organism originally cultured from the wounds. The incidence of vein graft disruption was lowest when the wounds were sterile (25%) or when gram-positive bacteria grew (25%). Gram-negative infection uniformly resulted in disruption of the exposed venous graft. When a new graft was placed, the secondary graft became reinfected in all patients with gram-negative primary graft infection. There were no instances of secondary graft reinfection when gram-negative bacteria were not present. These data suggest that the outcome of patients presenting with exposed vein grafts is highly dependent on the bacterial flora of the process. Vein graft disruption is frequent in patients with gram-negative infection, suggesting that these patients should be treated with distant graft ligation and extra-anatomic bypass. By contrast, patients without gram-negative infection may be successfully managed with local wound care.

Multiple intracerebral hemorrhages after smoking "crack" cocaine

After smoking "crack" cocaine and consuming large quantities of ethanol, a 36-year-old man developed multiple, bilateral, deep, and superficial cerebral hematomas. He was hypertensive for several days, but angiography revealed no evidence of vascular malformation or vasculitis. The multifocality of the hematomas and lack of underlying disease suggest that the hemorrhages resulted from cocaine-induced acute hypertension or arterial spasm, possibly potentiated by heavy ethanol consumption.

Factors determining survival after ruptured aortic aneurysm: the hospital, the surgeon, and the patient

The 10-year experience of a single community was reviewed and a multivariate analysis was performed to determine the relative importance of clinical and environmental factors in mortality after ruptured abdominal aortic aneurysm resection. Ruptured aneurysms were repaired in 243 patients in six area hospitals (one university, five community) by 25 surgeons (16 vascular, 9 general). Overall, 30-day mortality was 55% (133/243). Although the mortality by hospital ranged from 44% to 68%, these differences were not statistically significant. However, significant variations occurred in the mortality rates of individual surgeons, ranging from 44% to 73%. The mortality rate for the vascular surgeons was less than that of the general surgeons, 51% versus 69% (p less than 0.05). Clinical factors were evaluated, and the most significant parameters were systolic blood pressure, presence of chronic obstructive lung disease, and history of chronic renal insufficiency. These results support the implication that the degree of specialization of the surgeon and the preexisting health of the patient are the most important determinants of survival after ruptured abdominal aortic aneurysm. The size and sophistication of the hospital appear to be less influential factors.

Method in bioethics: a troubled assessment

This discussion is a critical assessment of the methods employed by some leading writers in the field of bioethics. The author agrees with those in the field who regard its primary or essential method as moral philosophy, but he nevertheless finds a prevalent tendency among bioethical writers merely to apply received moral principles to issues and to avoid penetrating theoretical analysis, even when such analysis is unavoidably required. He explains these deficiencies in terms of the exigencies of interdisciplinary work and the affinity of much early bioethics with policy- or legislatively-oriented "public ethics". The discussion ends with a call for increased theoretical sophistication in this field.

Differential effects of a gram-negative and a gram-positive infection on autogenous and prosthetic grafts

A canine model was developed to study the differential response of a gram-negative and a gram-positive bacterial infection on autogenous and prosthetic grafts. After replacing segments of the femoral arteries of 15 dogs with autogenous vein in one groin and polytetrafluoroethylene in the contralateral groin, 10(8) colony-forming units of nonmucin-producing Staphylococcus epidermidis (five dogs), Pseudomonas aeruginosa (five dogs), or sterile saline solution (five dogs) were directly inoculated onto the grafts. The grafts were examined 7 to 10 days after implantation. None of the control dogs exhibited inflammatory signs, and no grafts or anastomoses disrupted. S. epidermidis was unrecoverable from either graft material in any of the animals, although histologic evaluation confirmed neutrophils and bacteria in four of five animals in the vein and polytetrafluoroethylene groups. No dog inoculated with S. epidermidis had graft or anastomotic disruption. By contrast, P. aeruginosa was recovered from both types of grafts in all inoculated animals. Neutrophils, bacteria, and microabscesses were observed in all of these animals. In addition, three of five polytetrafluoroethylene grafts and all five vein grafts disrupted either at the anastomoses or in the body of the vein graft. Therefore S. epidermidis is a less virulent organism that may persist in graft walls despite negative cultures, whereas P. aeruginosa is a highly virulent organism that can disrupt native artery, vein grafts, and anastomoses. The graft material appears to be less important than the bacteria in determining the outcome of infection.

Comparison of infrainguinal graft surveillance techniques

One hundred seventy-seven patients with infrainguinal bypass grafts were followed by use of standard graft surveillance techniques to learn more about the natural history of hemodynamic abnormalities in the patient with no symptoms. A decrease in the ankle/brachial pressure ratio of 10% or more was considered an abnormal evaluation. Results of the duplex scan were interpreted as abnormal when the peak systolic flow velocity was greater than 120 cm/sec or less than 40 cm/sec. There were 18 graft thromboses (10%) during the period of observation, and nine of these grafts were successfully revised or replaced. Recurrent symptoms prompted graft revision in 20 additional patients, and 18 of these reoperations were successful. Twenty-nine of the 38 reoperations occurred within the first 18 months of the study. The primary cumulative patency rate was 86% at 1 year and 66% at 5 years. The secondary cumulative patency rate was 91% at 1 year and 80% at 5 years. Sudden graft occlusion occurred in five patients after a normal ankle/brachial index. Most of 90 patients with abnormal ankle/brachial indexes reverted to normal at the next visit. Nineteen of the 26 that did not, had significant graft problems, but only eight patients had operable conditions, and five of the eight already had occluded grafts. No patient with a normal ankle/brachial index and duplex scan results had graft occlusion before their next surveillance visit. If the duplex scan outcome was abnormal but the ankle/branchial index normal the incidence of sudden graft occlusion was 4%. In contrast, if the duplex scan outcome was abnormal and the ankle/brachial index is reduced, then the risk of graft occlusion is 66%.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo dental plaque-forming ability and cariogenicity of the bacterium Streptococcus bovis in gnotobiotic rats

Germ-free Fisher rats, fed on a high sucrose diet, were monoinfected with Streptococcus bovis strains. High levels of fissure caries were formed by three strains; one strain produced moderate levels; another produced only very low levels. No strain could produce approximal or buccal/lingual lesions. All strains could colonize the fissures of teeth in the lower jaw, as shown by scanning electron microscopy. The most cariogenic strains were associated with caries scores similar to those of Strep. salivarius and members of the mutants streptococci.

Reexploration for thrombosis in carotid endarterectomy

We reviewed the records of patients undergoing carotid endarterectomy and manifesting either postoperative stroke or thrombosis by oculopneumoplethysmography (OPG-Gee) to analyze the etiology of stroke and to determine the indications for reexploration. Of 900 consecutive elective endarterectomies performed during an 8-year period, 41 patients experienced a perioperative stroke, carotid thrombosis, or both. These patients were subdivided into three groups: group 1, 22 patients with perioperative stroke and carotid thrombosis; group 2, six patients with carotid thrombosis but without symptoms; and group 3, 13 patients with postoperative stroke but no thrombosis. In group 1, 17 patients were reexplored (group 1a), and five were observed without reexploration (group 1b). In group 2, three of the patients were reexplored (group 2a), and the remaining three were observed (group 2b). None of the group 3 patients were reexplored. In group 1a, four (23%) patients awoke from anesthesia with neurological deficits, whereas in group 3, nine (69%) patients awoke with such deficits. Follow-up at 30 days revealed that 76% of group 1a patients demonstrated improvement in symptoms, whereas similar results were seen in only 20% of group 1b patients and 23% of group 3 patients. These trends were maintained throughout the follow-up period of 1-5 years. Those patients who were asymptomatic, group 2, with thrombosis were more likely to have been operated on for asymptomatic carotid stenosis. with thrombosis were more likely to have been operated on for asymptomatic carotid stenosis. Thrombosis was the most common cause of postoperative stroke (63%) in patients after carotid endarterectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of fluoride-containing chewing gum on remineralization of carious lesions and on fluoride uptake in man

The remineralization effect of chewing gum containing fluoride (F) was studied on natural carious lesions. Maxillary acrylic appliances carrying the carious enamel sections were worn by three subjects. After 3 days of chewing 15 sticks of fluoride gum (Fluogum, containing 0.113 mg F/stick sweetened with xylitol/sorbitol), there was a significant reduction in both lesion depth and in the size of the body of the lesion (p less than 0.001). Exposure of carious lesions to 3 days in an oral environment without fluoride supplement reduced the size of the body of the lesions by an average of 5% (p less than 0.05). Chewing one or two sticks of the gum for 15 minutes raised the salivary-fluoride concentration to a peak of 1.13 ppm 5 minutes after chewing one stick, and raised the concentration to 2.73 ppm 10 minutes after chewing two sticks. The area under the curve of salivary-fluoride concentration versus time obtained following chewing one and two sticks were 0.78 h.microgram/ml and 1.89 h.micrograms/ml, respectively. There was a high positive correlation (r = 0.78) between the saliva flow and elimination of fluoride. Plaque fluoride level increased 1.7 fold following chewing two sticks of gum (p less than 0.05). The effect of chewing two sticks (a dose of 0.226 mg F) on plasma fluoride level was negligible, an indication of the safety of chewing gum regimen. More work is needed to document the cariostatic efficacy of a fluoride-containing chewing gum.

Attitudes of some young female bank employees to dentistry

Structured interviews were undertaken with one hundred 18-30-year-old females, seeking their views on dental care. Almost all regarded their own past experience as affecting their general level of dental anxiety. Over half were anxious about visiting the dentist and almost all of these were anxious before entering the surgery. The Anxious emphasized the negative features in dental care and the practice environment whereas the Non-anxious concentrated on positive features, particularly their relationship with the dentist. Many spontaneously commented that their attitudes had been improved by changing dentists, although some still remained anxious. 'Worst visits' had frequently occurred early in their lives. Appearance was of prime importance; function was ignored. Interviewees believed that visiting the dentist would be eased by lower costs, more convenient hours, better surroundings in the practice and improved techniques to make dentistry more comfortable.

Cutaneous vasculitis due to cyclophosphamide therapy for chronic lymphocytic leukemia

A 55-year-old male with chronic lymphocytic leukemia developed a skin eruption after receiving oral cyclophosphamide. Subsequent rechallenge with parenteral cyclophosphamide led to recurrence of the skin lesions, which on biopsy were shown to be vasculitic in nature.

Results of supraceliac aortic clamping in the difficult elective resection of infrarenal abdominal aortic aneurysm

We have used clamping of the aorta above the celiac axis (SC) in 30 of 431 elective resections of infrainguinal abdominal aortic aneurysms (AAA) during the past five years as an alternative to a difficult aortic cuff dissection. The results of SC clamping in these 30 patients are compared with the results of 379 routine aneurysm resections with infrarenal (IR) clamping and 22 additional aneurysm resections where the clamp was placed immediately above the renal arteries. These difficult cuff dissections occurred in 12 patients with inflammatory AAA, in 11 patients with juxtarenal AAA, and in seven patients with recurrent or noninfected false AAA of the proximal cuff. Patients with ruptured or suprarenal aneurysms and those undergoing combined operation for a visceral ischemic syndrome and an aneurysm were excluded from this study. Patients with SC clamping had similar operative mortality rates, comparable renal function, and frequency of cardiac events as patients with IR clamping. Blood loss was slightly higher in the SC group (p = 0.07) and serum aspartate amino transferase (AST) levels were three times higher than in the IR group; however, this was of no clinical significance. In contrast, those 22 patients whose aortas were clamped immediately above the renal arteries (AR) had higher perioperative mortality rates (2% IR, 3% SC vs 32% AR) and a higher incidence of kidney failure requiring dialysis (1% IR, 3% SC vs 23% AR). The mean values of serum creatinine and blood urea nitrogen were also significantly higher in the AR group when compared with both the IR and the SC groups (IR: 25 and 1.5 mg/dl, respectively; SC: 27 and 1.8 mg/dl; AR: 41 and 3.5 mg/dl). The single most important risk factor accounting for the differences between clamping above the celiac artery and clamping above the renal arteries was the presence of atherosclerotic debris in the nonaneurysmal, juxtarenal aortic segment. Clamping the aorta with juxtarenal atherosclerosis caused either atheroembolization to kidneys, legs, and intestine or injury to the aorta, renal arteries, or both; it was the cause of morbidity in all five cases of kidney failure requiring dialysis and accounted for all seven of the deaths in the AR group. SC clamping does not add risk to the patient undergoing resection of an infrarenal AAA and is the preferred method of achieving proximal control of the infrarenal aorta when a a hazardous cuff dissection is likely.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparative cariogenicity and dental plaque-forming ability in gnotobiotic rats of four species of mutans streptococci

The four species, each represented by two strains, all produced high levels of fissure caries in the upper and lower jaws of gnotobiotic Fisher rats. Streptococcus rattus strains and Streptococcus mutans NCTC 10832 gave low levels of approximal caries, whereas Streptococcus cricetus, Streptococcus sobrinus and Strep. mutans NCTC 10449 gave high levels. The only strains to produce buccal surface lesions were Strep. sobrinus and Strep. cricetus. All strains were able to form dense plaque in the central fissure of the second molar. Strep. cricetus, Strep. rattus and Strep. sobrinus strains were capable of producing smooth-surface plaque. This difference in plaque-forming ability did not correlate precisely with differences in cariogenicity, and such differences occurred between strains of the same species.

Renal clearance and protein binding of melphalan in patients with cancer

The renal clearance of melphalan and the fraction unbound in plasma were determined after intravenous infusion of 5 mg/m2 over 5 min in nine patients with cancer to obtain information regarding the mechanism of renal handling of melphalan. Four of the patients underwent bone marrow transplantation and also received an IV dose of 220 mg/m2. Total melphalan clearance after the 5 mg/m2 dose ranged from 66.0 to 272 ml/min per m2; the percentage of the dose excreted unchanged in urine, from 2.5% to 92.8%; renal clearance, from 4.1 to 188 ml/min per m2; the fraction unbound in plasma, from 0.0598 to 0.460; and t1/2 beta, from 39.4 to 84.3 min. Unbound melphalan clearance and renal clearance calculated from the unbound fraction in plasma for each patient ranged from 441 to 3356 ml/min per m2 and 15 to 961 ml/min per m2 respectively and were not related to serum albumin, serum creatinine or creatinine clearance. The percentage of the dose excreted and melphalan renal clearance were not related to urine flow. There was evidence of active secretion of melphalan in the kidney an possible reabsorption. There were no significant paired differences in melphalan disposition between the high- and low-dose studies. Highly variable renal clearance involving active secretion may contribute in part to large interpatient differences in the total plasma clearance of melphalan in patients with cancer.

Tooth wear and the position of the mental foramen

Variation in the position of the mental foramen with respect to the teeth ("apparent" position) seems to be associated with race, but in the determination of this position, factors which affect the disposition of the teeth plainly have a bearing on the results. The apparent position was investigated in a sample of southern Chinese skulls of known age which were classified by the degree of tooth wear. Controlling for "true" position and size of the mandible, a highly significant correlation between wear and position was found, age and tooth size having no significant contribution as additional explanatory variables. The effect of tooth wear on the apparent position of the foramen may partly explain racial variation.

Observations on cerebral computed tomography in patients having carotid endarterectomy

A review was undertaken of all patients seen in our institution between January 1978 and March 1987 in whom a cerebral CT scan was obtained in association with elective carotid endarterectomy. Three hundred fifty-nine such patients were identified. In a subgroup of 89 patients who were neurologically normal after carotid endarterectomy, scans were performed at least 48 hours after surgery to quantitate the incidence of silent postoperative infarction. These scans were interpreted by one neuroradiologist. Preoperative cerebral CT scans showed ipsilateral infarction in 146 of 359 patients (40.6%). Ipsilateral infarction was most common in patients with stroke (76%) but was also seen in 32.8% of patients with transient ischemic attacks, in 9 of 40 patients (22.5%) with nonhemispheric symptoms, and in 9 of 45 patients (20%) with asymptomatic hemodynamically significant carotid stenosis. The postoperative stroke rate was not significantly increased by the presence of infarct on preoperative cerebral CT scan (2.6% vs 1.9%). New infarcts were seen on cerebral CT scanning after carotid endarterectomy in 2 of 89 patients with no detectable neurologic abnormality (2.3%). This study demonstrates a high frequency of ipsilateral infarction in patients having elective carotid endarterectomy, even in those patients with clinical symptom complexes thought by many physicians to be relatively benign (i.e., transient cerebral ischemia, nonhemispheric ischemia, and asymptomatic carotid stenoses).(ABSTRACT TRUNCATED AT 250 WORDS)

Anomalous carotid-basilar anastomoses in cerebrovascular surgery

Primitive embryonic anastomotic vessels between the internal carotid and basilar arterial systems occasionally persist into adult life. We encountered six such patients in a series of 765 carotid endarterectomies (0.8%). These arteries are named for the cranial nerves with which they run. The most commonly found vessel is the trigeminal artery, followed by the hypoglossal and proatlantal intersegmental arteries. The primitive otic artery is the rarest of the four anomalous vessels. These vessels are usually large and are associated with hypoplasia or aplasia of the normal intracranial anastomotic channels. Cerebral ischemia is common during temporary intraoperative carotid occlusion and was encountered in two of three patients who had intraoperative electroencephalographic monitoring. Thus cerebral ischemia should be anticipated during carotid cross-clamping and cerebral protective measures should be instituted when persistent primitive cranial vessels are encountered.

Human central nervous system and plasma pharmacology of mitoxantrone

Mitoxantrone 5-6 mg/m2 was administered IV to 10 consenting patients prior to surgical resection of an intracerebral tumor. Plasma pharmacokinetic parameters were calculated and concentration of mitoxantrone in intracerebral tumors was determined. Concentrations of mitoxantrone were also determined in autopsy tissues of one of the patients who expired 192 days after receiving the drug. The plasma pharmacokinetics were best described by a 3 compartment model, with a tl/2 gamma of 4.74 +/- 5.53 h. Mitoxantrone concentrations in the intracerebral tumors were potentially cytotoxic and ranged from 4 to 322 ng/g. In all but one case, mitoxantrone concentration was higher in tumor than in concurrent plasma samples. There was no obvious relation between tumor mitoxantrone concentration and peak plasma mitoxantrone concentration or time from mitoxantrone administration to tumor removal. Low grade gliomas and viable tumors tended to have lower mitoxantrone concentrations than did other tumor types and necrotic tumors. In the patient undergoing autopsy, highest mitoxantrone concentrations were found in liver, thyroid and heart.

The effects of pentoxifylline on patients with intermittent claudication

All patients who had intermittent claudication (IC) over an 18-month period were given prescriptions for pentoxifylline (PTFX) 400 mg, three times daily. Patients were required to purchase their medication at a cost of $28 to $35 per month. The drug was administered regardless of the severity of symptoms, and no patient was offered operation without at least a 6-week trial of PTFX. An assessment of the severity of IC was made at the initial visit based on noninvasive data and the impact of the IC on the patient's life-style. One hundred thirty patients were enrolled in the study and were followed for 9 +/- 1 months. Patients were seen every 2 months for treadmill exercise or induced hyperemic testing and interviews until the effects of the medication were determined. The duration of IC before the start of treatment had no effect on the results. IC did not improve in 88 patients (71%) followed for 7.2 +/- 1 month. Thirty-six of these patients stopped the drug themselves because there was no benefit and the expense of PTFX was a hardship. An initial but short-lived improvement in walking was noted in another 13 patients (10%) following 14 +/- 2 months, and the medication was eventually discontinued. Only 23 patients (19%) followed for 11.6 +/- 2 months felt that IC had improved to the point where they did not feel limited in any way. Gastrointestinal symptoms occurred in 13 patients and were severe in eight patients (6%) who stopped taking the medication. The results of PTFX in this group of patients with IC were disappointing at best.(ABSTRACT TRUNCATED AT 250 WORDS)

A resolution of the ascertainment sampling problem: IV. Continuous phenotypes

This paper considers ascertainment corrections for continuous phenotypes. Two main points are considered. The first is a discussion of what ascertainment corrections can be devised to ensure asymptotically unbiased parameter estimates when the nature of the ascertainment procedure is not known. The second is an analysis of the properties of various forms of ascertainment correction possible when the nature of the ascertainment procedure is known. Some ascertainment corrections are thus shown to be valid and others invalid.

Suitability of human, bovine, equine, and ovine tooth enamel for studies of artificial bacterial carious lesions

The progress of artificial caries-like lesions created in human, bovine, equine, and ovine enamel has been studied. Lesions were produced by exposure to an acid gel system or by 5-day exposure to a sequential batch culture technique using Streptococcus mutans NCTC 10832. Longitudinal ground sections were prepared. The lesions were of similar appearance in all species when examined in polarized light. The depth in human enamel was approximately half that in the animal species. Microradiography confirmed subsurface demineralization in all four species. Similar depth ratios were seen in the scanning electron microscope, but there were structural differences between lesions in human and animal teeth. Lesions in bovine teeth were more like those in human, but lesions in equine and ovine teeth were markedly different. Substitution of these animal enamels for human enamel in caries experiments demands that these differences be taken into account. Scanning electron microscopy is capable of resolving features in artificial caries lesions which cannot be differentiated by polarized light techniques. The latter will demonstrate generalized mineral loss, but scanning electron microscopy is required to characterize the sites of mineral loss.