Direct and neurohumoral cardiovascular effects of atrial natriuretic peptide

We studied the hemodynamic changes produced in conscious, chronically instrumented rabbits during steady-state administration of atrial natriuretic peptide (ANP). We administered synthetic alpha-human ANP intravenously (i.v.) at progressively increasing doses of 1, 2, and 4 micrograms/min, each for 30 min. In different experiments in each rabbit, we determined the effects of the peptide under closed-loop conditions in the intact animal and the "direct" circulatory effects of the peptide after "total" blockade of the autonomic nervous system (TAB) and after combined neurohumoral blockade (NHB), where in addition the vascular effects of vasopressin and angiotensin II were also prevented. In intact rabbits, ANP produced a dose-related reduction in mean arterial pressure (MAP, -3 to -14%), which was entirely due to a fall in cardiac output (CO, -14 to -20%), and there was a small rise in total peripheral resistance (TPR 5-12%). Heart rate remained unchanged. In rabbits subjected to TAB and NHB, all hemodynamic effects of ANP were attenuated. There were dose-related falls in left and right atrial pressures which reached maxima of -3.3 +/- 0.9 and -1.8 +/- 0.2 mm Hg, respectively. There was a reversible rise in hematocrit, probably owing to a shift of approximately 8% in blood volume. These effects occurred mainly through direct actions of the peptide, and there was no evidence of systemic vasodilatation. The magnitude of reflex autonomic effects appeared to be less than expected for the observed fall in MAP, suggesting that ANP also inhibited cardiovascular reflexes.

Renal effects of atrial natriuretic peptide in conscious rabbits with renal wrap hypertension

Atrial natriuretic peptide (ANP, 2 micrograms/min) was infused intravenously into rabbits four weeks after renal wrap or sham operation. Mean arterial pressure (MAP) averaged 132 +/- 4 mmHg in the renal wrapped rabbits and 89 +/- 3 mmHg in the sham rabbits, and glomerular filtration rate (GFR) was significantly lower in the hypertensive rabbits (6.2 +/- 1.0 ml/min) than in sham rabbits (8.9 +/- 0.7 ml/min). In sham rabbits, ANP caused a significant diuresis, natriuresis and increase in GFR. Enalapril pretreatment blunted these responses. In the hypertensive rabbits, ANP reduced mean arterial pressure but did not cause significant diuresis or natriuresis or change in GFR. Enalapril pretreatment did not significantly alter this response to ANP. In separate experiments, nitroprusside was infused to lower arterial pressure in hypertensive rabbits by a similar amount to that achieved with ANP and this reduced GFR, sodium and urine excretion rates. Thus ANP maintained GFR and sodium excretion in hypertensive rabbits compared to an equihypotensive dose of nitroprusside. In summary, ANP did not cause natriuresis or diuresis in renal wrapped kidneys at a dose which was effective in normal kidneys, but did maintain GFR, sodium and water excretion rates, compared to an equally hypotensive dose of nitroprusside.

Double-blind randomized cross-over trial of dexamethasone and prochlorperazine as anti-emetics for cancer chemotherapy

A double-blind randomized cross-over trial of dexamethasone and prochlorperazine as adjunctive anti-emetics with cancer chemotherapy was undertaken. The drugs were compared for cisplatin, doxorubicin and several other chemotherapy regimens. A total of 44 eligible patients were analysed. Assessment was made by questionnaire answered by the patient 24 h after the chemotherapy. The parameters compared were period of time for nausea and vomiting, number of vomiting episodes, degree of somnolence and insomnia and overall preference. In all cases there was no significant difference for either drug in its ability to suppress emetic effects. Neither drug gave adequate protection against cisplatin-containing regimens. We conclude that dexamethasone alone is equivalent to the more standard dopamine antagonists.

Contribution of the kidney to metabolic clearance of atrial natriuretic peptide

To quantify the role of the kidney in whole body metabolic clearance rate (MCR) from plasma of atrial natriuretic peptide (ANP), synthetic alpha-human ANP-(1-28) was infused at 200 ng/min to steady-state conditions in chronically instrumented one-kidney conscious dogs. Clearances were measured in dogs with a normally filtering kidney and they were also measured after the glomerular filtration rate (GFR) was reduced to close to zero by acutely inflating a cuff around the renal artery (RAC), which resulted in minimal urine production and renal blood flow reduction to 59% of the resting level. In normal dogs, MCR was 1,090 +/- 134 ml/min with renal clearance rate (RCR) contributing only 13.9%. After RAC, MCR fell to 864 +/- 151 ml/min, due in part to a fall in RCR (-41.5 +/- 12.9 ml/min), but mostly due to a fall in "rest of the body" (total renal) clearance of ANP. The reduced GFR accounted for virtually all the fall in RCR. Normal plasma ANP half-life was 59.6 +/- 7.9 s. In conclusion, MCR of ANP was very high, approaching the cardiac output, suggesting that most of ANP is cleared in one circulation through peripheral tissues. GFR contributed significantly to RCR (approximately 30%) but the contribution of the kidney to whole body MCR was small relative to rest of the body clearance of ANP.

Simulation of acute haemorrhage in unanaesthetized rabbits

1. We have shown that it is feasible to match the linear rate of fall of cardiac output that occurs during haemorrhage at 2.7 ml/kg per min in unanaesthetized rabbits by constricting the thoracic inferior vena cava so as to decrease venous return. 2. The changes in systemic vascular resistance, arterial pressure and heart rate that occurred during haemorrhage were mimicked by simulated haemorrhage. They were reproducible when simulated haemorrhage was performed three times at 90 min intervals, and when it was repeated four times over 12 days. 3. Simulated haemorrhage caused rises in plasma renin activity (PRA) and plasma arginine vasopressin concentration (AVP) that were similar to those reported after haemorrhage. The response of PRA was unaffected by repeated simulated haemorrhage, but the response of AVP was less on the third occasion. 4. When the shed blood was re-infused after haemorrhage, cardiac output tended to remain low and systemic vascular resistance high. After simulated haemorrhage, all haemodynamic variables returned to normal within 2 min of releasing the caval cuff. 5. Haematocrit fell during haemorrhage, and remained low for at least 5 days after replacement of the shed blood. Haematocrit was unaffected by simulated haemorrhage. 6. Venous pressure below the inflatable cuff rose by 6 mmHg in the course of simulated haemorrhage. 7. We conclude that the central haemodynamic effects of haemorrhage can be closely and repeatedly simulated by inflating a cuff on the inferior vena cava. This provides a useful technique for repeatedly studying the effects of acute reduction of central blood volume in conscious animals.

Cisplatin plus VP 16-213 in advanced ovarian carcinoma

Thirty-five patients with advanced epithelial ovarian carcinoma (24 untreated, 11 previously treated with alkylating agents) were treated with a combination of cisplatin and etoposide (VP16-213). Tumor response (i.e., complete response and partial response) was seen in 16 of the 35 patients (i.e., 46%), with 5 complete responses. The response rate in previously untreated patients was 54%, but only 27% in previously treated patients. The median survival was 42 weeks. The toxicity of this regimen was severe. Twelve patients became severely myelosuppressed, including one septic death while severely neutropenic. Treatment with cisplatin and etoposide produces only average tumor response rates and patient survival, but is associated with severe toxicity. There is no evidence of synergy between cisplatin and VP16 in this study.

Decreased renal responses to atrial natriuretic peptide in renal wrap hypertension

1. The effects of atrial natriuretic polypeptide (ANP) on renal function were examined in renal wrap hypertensive rabbits and sham operated rabbits. 2. ANP (2 micrograms/min) induced hypotension, but did not produce significant diuresis, natriuresis or change in the glomerular filtration rate (GFR) in renal wrap hypertensive rabbits (n = 8). 3. In sham operated normotensive rabbits (n = 4), ANP induced significant diuresis (230%) and increased GFR by about 40%. 4. Thus, ANP was markedly less effective in the impaired kidneys of renal wrapped rabbits than in normal kidneys.

Exaggerated atrial natriuretic peptide release during acute exercise in essential hypertension

The effects of acute exercise on plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin (AVP), and plasma renin activity (PRA) were studied in 13 patients with previously untreated essential hypertension, and 8 matched normotensive control subjects. Resting levels of ANP and PRA were similar in the two groups, while resting AVP concentrations were 1.4 times higher in hypertensive subjects. Graded exercise was performed on a bicycle ergometer with workload increased each minute until exhaustion (Wmax). Wmax was higher in normal subjects than in hypertensive patients. Blood pressure and heart rate rose more steeply in hypertensive patients. Plasma ANP increased during acute exercise in both groups, but the average increase in hypertensives was substantially greater than in normal subjects (P less than 0.05). The increase in ANP during exercise was greater in hypertensives with left ventricular (LV) hypertrophy, and there was a positive correlation between LV mass and the percentage rise in ANP during exercise (r = 0.56, P less than 0.005). Plasma AVP did not alter during exercise. Plasma renin concentrations showed a small rise during exercise in both groups, which was 16% less in hypertensive subjects (P less than 0.05). The enhancement of ANP release during exercise in hypertensive subjects may reflect both cardiac structural changes and increased redistribution of blood to the cardiopulmonary compartment.

Long-term survival in small cell lung carcinoma

We assessed outcome in 208 patients with small cell lung carcinoma two to seven years after treatment with combination chemotherapy, with or without chest and cranial radiotherapy. Fourteen patients (6.7%) survived cancer free for 30 months or longer. Nine of these (64%) had limited disease at diagnosis and four others had extensive disease with only one metastatic site. Two patients remain alive and disease free more than five years after diagnosis but median survival is still only 3.2 years. One patient died from intercurrent causes at 5.4 years but was free from small cell lung carcinoma at autopsy. Six patients are alive and disease free at intervals greater than 30 months but less than five years from diagnosis. All surviving patients are fully active with lifestyles similar to that prior to diagnosis. Five patients died from small cell lung carcinoma which relapsed more than 30 months after diagnosis. A few patients with small cell lung carcinoma are cured but 30-month survival is insufficient to show cure as late relapses do occur. Late toxicity from aggressive therapy does not appear to outweigh the benefits of long-term survival and potential cure in small cell lung carcinoma.

Improving the quality of life during chemotherapy for advanced breast cancer. A comparison of intermittent and continuous treatment strategies

Since chemotherapy for metastatic breast cancer is not curative, consideration of the quality of life is important in selecting a treatment regimen. We conducted a randomized trial comparing continuous chemotherapy, administered until disease progression was evident, with intermittent therapy, whereby treatment was stopped after three cycles and then repeated for three more cycles only when there was evidence of disease progression. Each approach was tested with doxorubicin combined with cyclophosphamide or with cyclophosphamide combined with methotrexate, fluorouracil, and prednisone. Intermittent therapy resulted in a significantly worse response (P = 0.02 by Mann-Whitney test), a significantly shorter time to disease progression (relative risk based on proportional-hazards model, 1.8; 95 percent confidence interval, 1.4 to 2.4), and a trend toward shorter survival (relative risk, 1.3; confidence interval, 0.99 to 1.6). The quality of life was expressed as linear-analogue self-assessment scores for physical well-being, mood, pain, and appetite and as a quality-of-life index. It improved significantly during the first three cycles, when all patients received treatment. Thereafter, intermittent therapy was associated with worse scores for physical well-being (by 23 percent of scale; 95 percent confidence interval, 11 to 35 percent), mood (25 percent; 13 to 37 percent), and appetite (12 percent; 0 to 24 percent) and for the quality-of-life index as indicated by the patient (14 percent; 5 to 23 percent) and the physician (16 percent; 7 to 26 percent). Changes in the quality of life were independent prognostic factors in proportional-hazards models of subsequent survival. We conclude that, as tested, continuous chemotherapy is better than intermittent chemotherapy for advanced breast cancer.

Lesions of A1 noradrenergic cells affect AVP release and heart rate during hemorrhage

The role of A1 noradrenergic cells of the ventrolateral medulla in the changes in mean arterial pressure (MAP), heart rate (HR), and plasma arginine vasopressin (AVP) after slow continuous hemorrhage (2% blood vol/min up to 35%) was examined by comparing responses in conscious rabbits before and 3 wk after a sham operation or A1 lesions. In the control experiments, MAP fell minimally up to the withdrawal of 20% of blood volume after which it fell abruptly to 20-30 mmHg below control by the 35% level. Plasma AVP increased nonlinearly during progressive hemorrhage with significant increases occurring only after 25% of blood volume was removed. In contrast, HR increased linearly after the onset of bleeding. After A1 lesions, which destroyed 84% (range 80-94%) of the noradrenergic cells, the amount of AVP released and the tachycardia during hemorrhage were reduced by 83 and 61%, respectively (P less than 0.005), but the fall in MAP was minimally affected. Basal values of MAP, HR, or plasma AVP were not affected by the lesions. These results suggest that during hemorrhage in conscious rabbits A1 noradrenergic neurons are important for the secretion of AVP and the reflex tachycardia but play little role in the maintenance of blood pressure.

Metastatic adenocarcinoma of unknown primary site. A randomized study of two combination chemotherapy regimens

Of 101 patients with symptomatic adenocarcinoma or undifferentiated carcinoma of unknown primary site, 95 were evaluable for the effects of two randomized chemotherapy regimens. Forty-eight patients received combination doxorubicin and mitomycin C (DM) and 47 received combination cisplatin, vinblastine and bleomycin (PB). Response rates were not significantly different between the two treatment groups, 42% for DM and 32% for PVB, with an overall response rate of 37.1%. Survival differences for DM and PVB treated groups were not significantly different, with 18 weeks and 25 weeks median survivals respectively. Toxicities were unequal for the two treatment groups with increased haematological toxicity for DM and greater gastrointestinal toxicity for PVB. The authors conclude both therapies were of limited efficacy in the treatment of ACUP patients and emphasize that only symptomatic patients should be considered for such therapies.

Chemotherapy of adult soft tissue sarcoma with combination of doxorubicin and methotrexate

Thirty-six adult patients with measurable advanced soft tissue sarcoma were treated with a combination of doxorubicin (70 mg/m2) and methotrexate (50 mg/m2) iv every 21 days. Partial remission was seen in ten of 33 evaluable patients (30%). Median duration of remission was 23 weeks, and median survival was 42 weeks. Bone marrow toxicity was the main toxic effect; 23% of the patients had a nadir leukocyte count less than 2.0 X 10(9)/L during therapy. These results do not suggest any therapeutic advantage in adding methotrexate to doxorubicin in this context.

A prospective randomized trial of single-agent versus combination chemotherapy in meningeal carcinomatosis

Forty-four patients with documented meningeal carcinomatosis (small-cell lung carcinoma [SCLC], 29%; breast carcinoma, 25%) were treated in a prospective randomized trial with intrathecal methotrexate (MTX) 15 mg or MTX plus cytosine arabinoside (Ara-C) 50 mg/m2. Most patients received intrathecal hydrocortisone (HC) each treatment to minimize arachnoiditis. Overall response was 55%. Seven patients achieved complete response. Response to MTX was superior to combined MTX/Ara-C, but not significantly so (61% v 45%; P greater than .10). Response was more frequent if drugs were administered via Ommaya reservoir than by lumbar puncture (65% v 48%; P greater than .10). Concurrent radiotherapy to the CNS was associated with significantly better response (73% v 35%; P less than .05). Small-cell lung carcinoma patients showed the best response (69%). Overall median survival for the whole group was 8 weeks, but responders fared better than nonresponders (median survival, 18 v 7 weeks; P less than .05). Nausea and vomiting were the most common toxicities encountered (45%), but rarely proved limiting. An unusual, previously undocumented reaction to intrathecal HC was noted. MTX is moderately effective in nonleukemic meningeal carcinomatosis, but the addition of Ara-C does not appear to improve results. Pretreatment factors did not predict outcome in this trial.

Vasopressin release in sheep following various degrees of rehydration

Restriction of the water intake of sheep to 0.5 1/day for 7-9 days increases plasma arginine vasopressin (pAVP), and voluntary rehydration causes a rapid fall in pAVP with no change in plasma osmolality. The extent of that inhibition of AVP release was assessed by comparing the decline of pAVP after drinking with pAVP disappearance curves obtained in the same sheep after stopping a constant infusion of AVP at 0.5 micrograms/h, which increased pAVP to the dehydration level. The fall in pAVP after drinking was almost identical with the disappearance curve showing that AVP release was almost completely inhibited during the 2-3 min taken for the sheep to drink 3-5 liters to satiate themselves. The response seemed, therefore, to be cued before the intake reached the satiating volume. When dehydrated sheep drank only 0.5 or 1.0 liter, in 30 s or less, pAVP again fell rapidly but only to a minimum approximately 15 min after drinking. The pAVP was unaltered in dehydrated sheep presented with water but denied access to it. Thus satiation was not necessary for rapid inhibition of AVP release after drinking, but satiation was necessary for this inhibition to be maintained. The initial inhibition was associated with falls in hematocrit and plasma total protein but not plasma osmolality. This isosmolar dilution occurred even in sheep that saw but were denied access to the water and suggests a shift of fluid from the extravascular space.

Renal responses to angiotensin II in conscious dogs: effects of aspirin and indomethacin

1. Angiotensin II was infused into the renal artery of unanaesthetized dogs at 0.4 and 2.0 ng/kg per min for 40 min each. 2. Indomethacin (3 mg/kg, and 1 mg/kg per h infusion i.v.) accentuated the angiotensin II-induced falls in glomerular filtration rate, renal blood flow and urine flow rate. Indomethacin did not alter the effects of angiotensin II on Na+ or K+ excretions. 3. Aspirin (35 mg/kg p.o. 2.5 h and 0.5 h prior to experiment) did not significantly change the renal effects of angiotensin II. 4. Both aspirin and indomethacin accentuated renal vasoconstriction during briefer (5 min) angiotensin II infusion. 5. Thus indomethacin and aspirin had markedly different effects on the actions of angiotensin II in the kidney. This suggests that at least one of these drugs has actions which affect angiotensin II-mediated vasoconstriction other than via cyclooxygenase inhibition.

Renal actions of angiotensin II in renovascular hypertension

In renal artery stenosis severe enough to cause hypertension, angiotensin II maintains glomerular filtration rate (GFR) both in the initial high renin phase of hypertension and later when plasma levels are normal. Angiotensin II also maintains GFR in less severe stenosis, which does not cause hypertension. This homeostatic action of angiotensin II to maintain GFr has minimal effects on blood flow. In renal-wrap hypertension, plasma renin levels are elevated for longer than after renal artery stenosis, but in other respects this initial phase of the hypertension is similar to that after renal artery stenosis. GFR is reduced, the rate of development of hypertension is accelerated by angiotensin II, and angiotensin II maintains the glomerular filtration fraction. Renal resistance is markedly increased owing to both compression of the kidney by the hypertrophying renal capsule and to angiotensin II. Thus angiotensin II apparently plays a primarily homeostatic role in renovascular hypertension to maintain glomerular ultrafiltration. It is suggested that the angiotensin II may be formed intrarenally and may act on sites other than resistance blood vessels.

Cardiac and arterial baroreceptor influences in release of vasopressin and renin during hemorrhage

We studied the role of arterial and cardiac baroreceptors on mean arterial pressure (MAP) and release of arginine vasopressin (AVP) and plasma renin activity (PRA) during hemorrhage in conscious rabbits. Each rabbit was bled at 2% of its blood volume (BV) per minute until 35% had been removed, after which the blood was reinfused. Each rabbit was studied on three occasions, 7 days apart, and in each experiment, BV-MAP and BV-hormone response curves were constructed. The response to hemorrhage was examined when the input from arterial and cardiac baroreceptors were both intact; arterial baroreceptors only were intact (cardiac receptors were blocked with intrapericardial procaine); cardiac receptors only were intact (after sinoaortic denervation); neither receptor was intact. Resting AVP and PRA levels were unaffected by the various deafferentation procedures. AVP steeply increased only after more than 25% BV had been removed; this response was entirely mediated by cardiac baroreceptors. Increases in PRA occurred at BV loss greater than 15% and were largely independent of baroreceptor input. Maintenance of MAP during hemorrhage was mostly due to drive from the arterial baroreceptors. Thus AVP secretion during hemorrhage contributes little to the maintenance of MAP, and the hypovolemic stimulus to AVP release comes entirely from the cardiac baroreceptors.

Randomised study of ticarcillin, cefamandole with or without tobramycin in febrile, neutropenic patients with solid tumors

A prospective randomised study was conducted comparing the efficacy and toxicity of the antibiotics ticarcillin and cefamandole (TC) with or without tobramycin (TCT) in 100 febrile neutropenic patients with solid tumours undergoing conventional chemotherapy. In this study, neutropenia less than 100/microliter was noted in 31% of 106 evaluable infectious episodes and neutrophil counts less than 1,000/microliter persisted for a median 4 days. Infection was microbiologically documented in 42% of episodes (bacteremia 24%) with gram-negative organisms responsible for 63% of bacterial isolates. Overall, 65% of episodes responded to TC and 76% to TCT (p greater than 0.05). Patients with initial shock bacteremia, pulmonary infection, or gram-negative sepsis responded relatively poorly. Neutrophil nadir and pathogen susceptibility did not influence outcome. Antibiotic toxicity was minimal with no tobramycin-related nephrotoxicity. These results are broadly comparable to those observed with leukemic patients, but the relatively short duration of neutropenia in the solid-tumour patients appears to minimize the need for additional antibiotics provided there is adequate antimicrobial coverage with the initial choice of antibiotics.

Superior vena caval obstruction: a 10-year experience

One hundred and fifty-nine patients with symptoms of superior vena caval obstruction who presented to two major hospitals over a 10-year period, from 1970 to 1979, were reviewed. Lung cancer was the most common histological diagnosis. The most common symptoms were dyspnoea and a feeling of fullness in the head. The most common physical findings were dilatation of the neck or chest wall veins, or oedema of the face and arms. Superior mediastinal widening was the most common radiological abnormality. No significant morbidity was associated with any diagnostic procedure. Only patients with lymphoma had a significantly longer survival period, both from the diagnosis of the disease, and from the onset of the symptoms of superior vena caval obstruction. There is no evidence that superior vena caval obstruction is an absolute medical emergency. Appropriate diagnostic steps should be undertaken to establish the histological diagnosis. The prognosis for some tumour types may be improved by combined modality therapy (chemotherapy plus radiotherapy).

Analysis of a prospectively randomized comparison of doxorubicin versus 5-fluorouracil, doxorubicin, and BCNU in advanced gastric cancer: implications for future studies

A multi-institutional cooperative study of patients with locally advanced, recurrent, or metastatic gastric adenocarcinoma who had not previously received chemotherapy was conducted, prospectively randomizing patients to receive either doxorubicin or the three-drug combination, 5-fluorouracil (5-FU), doxorubicin (Adriamycin; Adria Laboratories, Columbus, Ohio), and BCNU (FAB). The 187 evaluable patients were initially stratified according to the presence of measurable or evaluable disease and performance status. There was a significantly higher response rate observed for FAB (40%) compared with doxorubicin (13%) among the 145 measurable-disease patients. Duration of response and survival were significantly longer for FAB in the measurable-disease group, but for the total patient population an early advantage for FAB in time to disease progression and survival was lost with continued follow-up. Median survival was 33 weeks for patients receiving FAB and 19 weeks for those receiving doxorubicin. Significant pretreatment factors adversely affecting survival included poor performance status, weight loss of greater than 10%, and more than two sites of metastases. Toxicity was not severe in either treatment arm, and only thrombocytopenia occurred significantly more often with FAB. It is contended that in the treatment of advanced gastric cancer, chemotherapy only exerts a relatively short-term and modest beneficial effect, most apparent in patients with intermediate tumor bulk. 5-FU remains the most active single agent, and combination chemotherapy has not yet proven its overall worth. Further studies are indicated comparing the most active combinations with 5-FU using optimal doses and schedules, and consideration must be given to the incorporation of no-treatment controls.

Renal and systemic effects of enalapril in chronic one-kidney hypertension

We have investigated the role of angiotensin II in the development of high blood pressure and in the maintenance of renal function during 2 weeks of one-kidney renal artery stenosis in conscious dogs. Responses to a fixed degree of inflation of a balloon cuff around the renal artery were compared in dogs with or without continuous enalapril (MK 421) treatment. In six untreated dogs, mean aortic pressure was increased by 17.1 +/- 2.0 mm Hg, due primarily to increases in total peripheral resistance with little change in cardiac output, while glomerular filtration rate, renal blood flow, renal artery pressure, and plasma renin activity were back to prestenosis levels. In seven enalapril-treated dogs mean aortic pressure was increased by 23.0 +/- 2.7 mm Hg and was not significantly different from that occurring in untreated dogs. This rise was due to increases in total peripheral resistance (10%) and cardiac output (12%). In the absence of angiotensin II, glomerular filtration rate remained low, at only 56 +/- 6% of prestenosis levels. Renal blood flow returned to normal, but the renal artery pressure remained 25% lower than control values. Thus, the main role of angiotensin II in chronic one-kidney Goldblatt hypertension does not appear to be through its pressor properties but rather through its actions in the kidney to preserve glomerular filtration. This effect on renal function persisted throughout the course of the hypertension, even when the plasma renin levels returned to normal.

Systemic and renal hemodynamic changes during acute unilateral renal arterial stenosis

The acute effects of unilateral renal arterial stenosis on systemic and renal hemodynamics were studied in chronically instrumented, conscious dogs. Graded stenosis of one renal artery for 90 min produced graded increases in arterial blood pressure and plasma renin activity and falls in contralateral renal blood flow and total peripheral conductance. There were no significant changes in cardiac output. The changes were transient after mild or moderate renal arterial stenosis but were sustained after severe stenosis. Pentolinium treatment did not significantly affect the hypertension or contralateral renal vasoconstriction caused by moderate or severe renal arterial stenosis. This indicates that the autonomic nervous system did not play a major role in the response to stenosis. In contrast, teprotide abolished the increases in arterial pressure, the contralateral renal vasoconstriction, and the fall in total peripheral conductance in response to stenosis. Thus the acute hypertension following unilateral renal arterial stenosis was due to a decrease in total peripheral conductance caused by decreased conductance of the stenotic kidney due to the stenosis itself (about 20%); vasoconstriction of the contralateral kidney (about 20%), and vasoconstriction of other systemic vasculature (about 60%). The results suggest that angiotensin II was responsible for the vasoconstriction of both the contralateral kidney and the other systemic vasculature.

Cisplatin, vinblastine, and bleomycin in inoperable non-small cell lung cancer

Forty two patients with inoperable non-small cell lung cancer were entered into a phase II study of the combination chemotherapy regimen PVB (cisplatin 60 mg/m2 by intravenous infusion over two hours on day 1, vinblastine 4 mg/m2 by intravenous bolus on days 1 and 2, and bleomycin 15 mg intramuscularly on days 1, 8, and 15), repeated at three weekly intervals. Twelve of 40 evaluable patients (30%) achieved partial responses; there were no complete responses. The median duration of response was 16 weeks (range greater than 8-73 weeks). The median survival of responding patients calculated from entry to the study until death (40 weeks) was superior to that of patients failing to respond (15 weeks). Treatment was accompanied by signs of moderate toxicity, particularly myelosuppression, nausea and vomiting, alopecia, and neuropathy. One patient died from a neutropenic infection. PVB is a moderately toxic regimen for non-small cell lung cancer and appears similar in efficacy and toxicity to high dose cisplatin and vindesine.