A randomized phase II study comparing capecitabine alone with capecitabine and oral cyclophosphamide in patients with advanced breast cancer-cyclox II

BACKGROUND

Capecitabine and cyclophosphamide are active in patients with advanced breast cancer, have non-overlapping toxic effects and synergy pre-clinically. We explored the efficacy and toxic effect of an all-oral combination of capecitabine with cyclophosphamide versus capecitabine alone in a multicentre, randomized, phase II study.

PATIENTS AND METHODS

Patients with locally advanced or metastatic breast cancer were randomized to treatment with capecitabine given continuously (666 mg/m(2) b.i.d. days 1-28) alone (C) or with oral cyclophosphamide (100 mg/m(2) days 1-14 of a 28-day cycle) (CCy) for up to six cycles.

RESULTS

Eighty-two patients were randomized. There was no complete response. The proportions with partial response were 36% on C and 44% on CCy, a difference of 7.9% [95% confidence interval (CI) -13.4 to 29.1]. Significant toxic effect was uncommon: grade ≥3 diarrhoea in 4 (10%) versus 1 (3%) patients; grade ≥3 fatigue in 2 (5%) versus 5 patients (13%) and grade ≥2 hand-foot syndrome in 7 (17%) versus 11 (28%) patients receiving C versus CCy, respectively. Median progression-free survival was 3.1 months on C and 6.9 months on CCy, not significantly different statistically. There was no difference in overall survival.

CONCLUSION

The difference in tumour response suggests a reasonable chance that CCy is superior to C alone.

Malaria therapy reinoculation data suggest individual variation of an innate immune response and independent acquisition of antiparasitic and antitoxic immunities

Malaria therapy reinoculation data were examined for the possible detection of effects attributable to stable individual host-specific factors, through correlation between descriptive variables of first and second infections. Such an effect was demonstrated with respect to the first local maximum of the asexual parasite density, i.e., the density at which a host controls parasite growth. The effect was seen between an individual host's first and second Plasmodium falciparum infection, as well as between an individual host's first malaria infection with P. ovale and second malaria infection with P. falciparum. We give reasons to believe that the main underlying mechanism is individual variation of an innate immune response. The data were also examined for systematic changes from first to second P. falciparum infection, as indicators of acquired immunity. In addition to the well-known reduction in parasite density, the data show the early development of apparent parasite tolerance. We give reasons to interpret the latter as antitoxic immunity.

Population dynamics of untreated Plasmodium falciparum malaria within the adult human host during the expansion phase of the infection

A retrospective analysis was performed of parasite count data recorded from the first 7 days of blood or mosquito transmitted Plasmodium falciparum infections given for the treatment of neurosyphilis in the USA before 1963. The objective of this study was to characterize initial growth dynamics before host defences have significant effects on the infecting parasite population. Of the 328 patients' data available for analysis, 83 were excluded because they had received anti-malarial treatment during the first 7 days of the patent infection. Nonlinear mixed effects modelling was performed to estimate the parameters of interest; 'parasite multiplication rate per 48 h' (PMR), and length of the parasite life-cycle (periodicity). The parasitaemia versus time profiles showed great variability between patients. The mean population estimate of 'PMR' was approximately 8, and was highly dependent on the P. falciparum 'strain'. PMR also varied significantly between patients with a 90% prediction interval varying from 5.5 to 12.3-fold. Both intrinsic parasite multiplication rate (an intrinsic virulence determinant), and host susceptibility and defence contribute to expansion of the parasite biomass and thus disease severity in falciparum malaria.

Follow-up strategies for patients treated for non-metastatic colorectal cancer

BACKGROUND

It is common clinical practise to follow patients with colorectal cancer (CRC) for several years following their definitive surgery and/or adjuvant therapy. Despite this widespread practice there is considerable controversy about how often patients should be seen, what tests should be performed and whether these varying strategies have any significant impact on patient outcomes.

OBJECTIVES

To review the available evidence concerning the benefits of intensive follow-up of colorectal cancer patients with respect to survival. Secondary endpoints include time to diagnosis of recurrence, quality of life and the harms and costs of surveillance and investigations.

SEARCH STRATEGY

Relevant trials were identified by electronic searches of MEDLINE, EMBASE, CINAHL, CANCERLIT, Cochrane Controlled Trials Register, Science Citation Index, conference proceedings, trial registers, reference lists and contact with experts in the field.

SELECTION CRITERIA

Only randomised controlled trials comparing different follow-up strategies for patients with non-metastatic CRC treated with curative intent were included.

DATA COLLECTION AND ANALYSIS

Trial eligibility and methodological quality were assessed independently by the three reviewers.

MAIN RESULTS

Five trials were included. There was evidence that an overall survival benefit at 5 years exists for patients undergoing more intensive follow-up (OR = 0.67, 95% confidence interval 0.53 - 0.84; RD = -0.07, CI -0.12 - -0.02). The absolute number of recurrences was similar (OR = 0.91; 95% confidence interval 0.72 - 1.14; RD = 0.00, CI -0.07 - 0.07) and although the weighted mean difference for the time to recurrence was significantly reduced by 6.75 (95% confidence interval -11.06 - -2.44) there was significant heterogeneity between the studies. Analyses demonstrated a mortality benefit for performing more tests versus fewer tests (OR = 0.66; 95% confidence interval 0.46 - 0.95) and liver imaging versus no liver imaging (OR = 0.66; 95% confidence interval 0.46 - 0.95). However when both these results are expressed as a risk difference this significance is lost (RD = -0.06; CI -0.25 - 0.13). No useful data on quality of life, harms or cost-effectiveness were available for further analysis.

REVIEWER'S CONCLUSIONS

The results of our review suggest that there is an overall survival benefit for intensifying the follow-up of patients after curative surgery for colorectal cancer. Because of the wide variation in the follow-up programmes used in the included studies it is not possible to infer from the data the best combination and frequency of clinic (or family practice) visits, blood tests, endoscopic procedures and radiological investigations to maximise the outcomes for these patients. Nor is it possible to estimate the potential harms or costs of intensifying follow-up for these patients in order to adopt a cost-effective approach in this clinical area. Large clinical trials underway or about to commence are likely to contribute valuable further information to clarify these areas of clinical uncertainty.

Genesis, sequestration and survival of Plasmodium falciparum gametocytes: parameter estimates from fitting a model to malariatherapy data

Plasmodium falciparum malaria is one of mankind's main killers. Part of the parasite's life-cycle is spent in human blood, mainly as asexual stages. A fraction of the asexual parasites develops into gametocytes (gamete precursors) while sequestered in deep tissues. After re-entering the circulation, gametocytes can be picked up by a mosquito to continue the parasite's life-cycle. We present estimates of the conversion probability from asexual parasites to circulating gametocytes and of the gametocytes' sequestration and circulation times, obtained for the first time by fitting a dynamic model to individual patients' histories (daily records of 113 neurosyphilitic patients undergoing malariatherapy). The model assumes that the conversion probability can vary among the successive waves of asexual parasitaemia of a patient, and that gametocytes die at an age-dependent rate which increases under high asexual parasite densities. On average, 1 gametocyte per 156 asexual parasites (range 7.4-3700) is produced. The most remarkable findings are the large individual variation of conversion probabilities and circulation times, the average gametocyte circulation time of 6.4 days (range 1.3-22.2 days) which is more than twice the currently accepted value, and the large variation of conversion probabilities among successive waves of asexual parasitaemia without any particular time pattern. The latter finding could be explained by an association between conversion probability and variation of PfEMP1.

Plasmodium malariae blood-stage dynamics

We examine the dynamics of parasitemia, fever, and gametocytemia reflected in the preintervention charts of 180 malaria-naive U.S. neurosyphilis patients infected with the USPHS strain of Plasmodium malariae, for malariatherapy, focusing on the 84 charts for which more than 35 days of patency preceded intervention and daily records encompassed 92% or more of the duration of each infection. Inoculum size did not influence any outcome variable. Fevers (days with temperatures > or =101 F) followed patterns that fit recognized brood structures more often than did our approximations of merogony cycles (via local peaks in parasitemia), but neither closely fit textbook quartan patterns. There were no discernable patterns in gametocytemia. Successful transmission to mosquitoes increased following subcurative drug treatment but did not depend on detectable gametocytemia.

Plasmodium falciparum parasitaemia described by a new mathematical model

A new mathematical model of Plasmodium falciparum asexual parasitaemia is formulated and fitted to 35 malaria therapy cases making a spontaneous recovery after primary inoculation. Observed and simulated case-histories are compared with respect to 9 descriptive statistics. The simulated courses of parasitaemia are more realistic than any previously published. The model uses a discrete time-step of 2 days. Its realistic behaviour was achieved by the following combination of features (i) intra-clonal antigenic variation, (ii) large variations of the variants' baseline growth rate, depending on both variant and case, (iii) innate autoregulation of the asexual parasite density, variable among cases, (iv) acquired variant-specific immunity and (v) acquired variant-transcending immunity, variable among cases. Aspects of the model's internal behaviour, concerning variant dynamics, as well as the respective contributions of the three control mechanisms (iii) - (v), are displayed. Some implications for pathogenesis and control are discussed.

Successful high dose therapy for relapsed mediastinal large B cell lymphoma following surgical repair of anterior chest wall defect

We describe a man with relapsed large B cell mediastinal lymphoma and associated infected large anterior chest wall defect who required high dose salvage therapy for his underlying disease. An initial mediastinotomy wound, associated with recurrent sepsis, had developed into an abscess, then fistula and eventually a large anterior chest wall defect. Safe use of salvage chemotherapy required reconstructive surgery consisting of a pedicled muscle flap. The subsequent high dose chemotherapy was carried out without complications and 15 months later the patient is alive and well.

Modelling the transition of asexual blood stages of Plasmodium falciparum to gametocytes

In this paper, we investigate the transition of asexual blood stages of P. falciparum to gametocytes. The study is based on daily data, collected from 262 individual courses of parasitaemia. We propose several mathematical models that follow biological reasoning. The models are fitted with maximum likelihood and are compared with each other. The models differ in the assumptions made about the mortality of circulating gametocytes and about the transition rate of the asexual parasites. Gametocyte mortality is modelled as being (i) constant over time, (ii) linearly increasing over time, (iii) linearly increasing over gametocyte age, and (iv) exponentially increasing over gametocyte age, respectively. The transition rate is either kept constant per patient or piecewise constant within intervals that correspond to waves of asexual parasitaemia which are assumed to be caused by different Pf(emp1)-variants. According to likelihood ratio tests, the models with age-dependent mortality rate and wave-dependent transition rates are superior to the models with constant transition rate and/or constant or time-dependent mortality rate. The best fits are reached for models with exponentially increasing (Gompertz-type) mortality. Furthermore, an impact of high asexual parasite densities on the survival of gametocytes, interpreted as a cytokine-mediated effect, is evident in some cases.

A retrospective examination of sporozoite- and trophozoite-induced infections with Plasmodium falciparum in patients previously infected with heterologous species of Plasmodium: effect on development of parasitologic and clinical immunity

A retrospective examination was made to determine parasitemia and episodes of fever in 97 patients, previously infected with Plasmodium malariae, P. ovale, and/or P. vivax, who were reinfected with P. falciparum for treatment of neurosyphilis, the standard treatment at the time. Data were collected at the National Institutes of Health laboratories in Columbia, South Carolina and Milledgeville, Georgia during the period 1940 to 1963. Results were compared with observations recorded for patients following primary infection with P. falciparum. The mean daily percentage of patients with fever > or = 101 degrees F during the first 20 days of primary infection with P. falciparum was 42.4; the percentage with fever > or = 104 degrees F was 19.9%. Those previously infected with P. ovale, P. vivax, and P. malariae had mean daily percentages of fever > or = 101 degrees F and > or = 104 degrees F of 39.1% and 14.8%, 39.1% and 19.4%, and 28.4%, and 11.3%, respectively. Previous infection with P. ovale or P. vivax had little, if any, effect on subsequent clinical malaria due to P. falciparum, whereas infection with P. malariae resulted in reduced frequencies of fever. A similar comparison was made for parasite counts > or = 1,000/microl and > 10,000/microl. The percentages for 268 patients during the first 20 days of primary infection with P. falciparum parasite counts > or = 1,000/microl and > or = 10,000/microl were 58.2% and 29.9%, respectively. Those previously infected with P. ovale, P. vivax, and P. malariae had mean daily percentages of parasitemia > or = 1,000/microl and > or = 10,000/microl of 58.0% and 24.3%, 57.3% and 31.1%, and 45.9% and 19.0%, respectively. Previous infection with P. malariae resulted in a reduction in the frequency of high-density parasitemia (> or = 10,000/microl) as well as an asexual parasite count > or = 1,000/microl. These results suggest that P. falciparum and P. malariae share common antigens that are able to induce parasitologic and clinical protection when infection with P. falciparum follows that with P. malariae. The results did not suggest that protection to P. falciparum is provided by previous infection with P. ovale or P. vivax.

A retrospective examination of the patterns of recrudescence in patients infected with Plasmodium falciparum

A retrospective examination was made to determine median intervals between recrudescences of Plasmodium falciparum in 343 neurosyphilitic patients who were given malariatherapy, which was routine care at that time. Data were collected at the National Institutes of Health laboratories in Columbia, South Carolina and Milledgeville, Georgia during the period 1940 to 1963. The geometric mean days of peak parasite count for the patients were 8, 26.5, 43.5, 62, 78.5, and 95.5 days, respectively. The intervals between these peaks of 18.5, 17, 18.5, 16.5, and 17 days suggest a fixed time frame for the appearance of different dominant parasite populations during the first 100 days of patent infection. When the data from these same patients were examined for mean peak parasite counts, the patterns indicated a consistent decrease in parasite count suggestive of increasing immunity, which was sufficient to reduce but not eliminate subsequent parasite populations. The geometric mean peak parasite counts for the 343 patients during the primary attack and the first 5 recrudescences were 40,350, 6,975, 5,090, 3,820, 3,455, and 2,375/microl, respectively.

A retrospective examination of sporozoite- and trophozoite-induced infections with Plasmodium falciparum: development of parasitologic and clinical immunity during primary infection

A retrospective analysis was made of the parasitologic and fever records of 318 patients who had been infected with the El Limon, Santee Cooper, or McLendon strains of Plasmodium falciparum for treatment of neurosyphilis between 1940 and 1963 to determine the development of parasitologic and clinical immunity during primary infection. The presence of fever > or = 101 degrees F and > or = 104 degrees F, asexual parasite counts > or = 1,000 and > or = 10,000/microl, and gametocyte counts > or = 100/microl and > or = 1,000/microl are presented. The frequency of fever (number of patients with fever/number of patients remaining in study) for the first 100 days of patent parasitemia, the frequency of parasite counts > or = 1,000 and > or = 10,000/microl during the first 100 days of patent parasitemia, and the frequency of gametocyte counts > or = 100 and > or = 1,000/microl during the first 100 days of patent parasitemia are presented for 4 groups of patients: 1) sporozoite-induced and 2) trophozoite-induced infections requiring treatment during their primary attack, and 3) sporozoite-induced and 4) trophozoite-induced infections not requiring treatment during the primary attack. For each sporozoite-induced infection, the route of inoculation (bites or syringe), the species of mosquito used, the number of mosquito glands or bites, the intensity of salivary gland infection, and the length of the prepatent period are recorded. Prepatent periods for 109 sporozoite-induced infections ranged from 6 to 28 days. Patients with parasitologic or clinical findings that required suppressive, but non-curative treatment, during the primary attack had higher frequency of fever, parasitemia, and gametocytemia than patients not so treated. Fever was concentrated in the first 2 weeks of patent parasitemia although instances of fever were reported >100 days after infection. High-density parasitemia was also concentrated early in the infection; instances of parasite counts > or = 10,000/microl occurred > 75 days after infection. In conclusion, immunity to infection with P. falciparum was shown to develop rapidly. Following primary infection, clinical and parasitologic immunity was evident within 2-3 weeks following the detection of parasites in the peripheral circulation.

A retrospective examination of secondary sporozoite- and trophozoite-induced infections with Plasmodium falciparum: development of parasitologic and clinical immunity following secondary infection

A retrospective study was made of clinical records to determine parasitemia and episodes of fever of 59 patients reinfected with Plasmodium falciparum for treatment of neurosyphilis, which was considered standard medical care at the time. Records were collected at the National Institutes of Health laboratories in Columbia, South Carolina and Milledgeville, Georgia during the period 1940 to 1963. Nineteen patients were infected via the bites of Anopheles albimanus, An. quadrimaculatus, or An. freeborni mosquitoes; the median prepatent period was 11.5 days. It was evident that clinical immunity, as measured by the frequency of fever, particularly high intensity fever (> or = 104 degrees F), was increased following reinfection. The parasitologic immunity, as measured by the frequency of asexual parasite counts and gametocyte counts, was also evident. In general, in secondary infections with homologous and/or heterologous strains of P. falciparum, fever episodes > or = 101 degrees F and > or = 104 degrees F were reduced in number, parasitemia was reduced, and gametocyte production was reduced. However, despite long courses of parasitemia during their primary infections, most patients developed fever and, in some cases, high-density parasitemia and gametocytemia following reinfection. The intensity of the secondary response did not appear to be associated with the length of the previous course of parasitemia. In addition, current infection with heterologous strain parasites did not prevent the development of fever or higher density parasite counts following imposition of the new strain of parasite.

A historical review of the F-1 strain of Anopheles freeborni as a host and vector for studies of malaria

A review was made of the use of a specific strain of Anopheles freeborni from California (F-1) that has been used extensively in experimental investigations of malaria for more than 50 years. The F-1 strain of An. freeborni has been shown to be a suitable experimental host and vector for different species of Plasmodium that cause malaria in humans and nonhuman primates for biologic, immunologic, and chemotherapeutic studies. Eleven species of Plasmodium fully completed sporogonic development; development of sporozoites within mature oocysts occurred in an additional 7 species. Transmission through An. freeborni from human to human, monkey to human, or monkey to monkey has been demonstrated for 9 species of Plasmodium.

Sister Joseph's nodule in non-Hodgkin's lymphoma

Sister Joseph's nodule is traditionally regarded as a sign of poor prognosis in untreatable malignancy. We describe a patient with a metastatic umbilical nodule in non-Hodgkin's lymphoma who had a good outcome. The possible mechanisms of tumour spread to the umbilicus and reasons for its rarity in lymphoma are discussed. The need for histological confirmation to exclude treatable disease is emphasized.

Endobronchial metastasis from rectal adenocarcinoma

A case of endobronchial metastasis 2 yr following treatment of rectal carcinoma is presented. Endobronchial metastases from extrathoracic primary malignancies are uncommon, the estimated frequency and possible mechanisms underlying this complication are discussed. The importance of recognizing possible endobronchial metastasis is in the approach to management and prognosis.

Primaquine resistance in Plasmodium vivax

Reports have appeared calling attention to what has been termed primaquine resistance in Plasmodium vivax in several geographic areas. The possibility exists that primaquine tolerant strains (often referred to as the tropical zone type from the South Pacific and Southeast Asian regions characterized by early and frequent relapses) may have become widely disseminated to areas where they had not previously existed through the widespread population mobility that has characterized the last 50 years. The appearance in the relatively recent past of strains of P. vivax, particularly from the South Pacific area, that are resistant to the 4-aminoquinolines has added a new dimension to the resistance problem. While there seems to be little evidence to date of the existence of acquired primaquine resistance in P. vivax, the possibility of its emergence in the future can certainly not be ruled out, and its timely detection and confirmation will be most important, albeit quite difficult because of the relatively covert sites of drug effect. The occurrence of relapses in P. vivax after primaquine therapy would be assumed to be the most reliable indication of resistance. Reports of the sporontocidal or gametocytocidal activity of primaquine when used alone (i.e., without concomitant administration of an effective suppressive) against a P. vivax infection have been few and inconclusive. The establishment of baselines of this activity in P. vivax might be useful in detecting and evaluating primaquine resistance in this species.

Infecting dose and severity of falciparum malaria

The causes of the wide spectrum of severity in malaria have only partly been elucidated. There are theoretical reasons for thinking that the infecting dose may influence the severity, but evidence is scare. We have analysed the records of 82 non-immune neurosyphilis patients bitten by a known number of mosquitoes infected with one of 3 strains of Plasmodium falciparum, whose treatment was delayed. After controlling for strain, the number of mosquitoes was not associated with the prepatent period nor with any of the outcome measures. For one of the main strains, patients with shorter prepatent periods were more likely to receive treatment during the acute phase of the infection, but no other association with measures of severity was found. This study suggest that infecting dose is unlikely to be an important determinant of severity.

CMV chemotherapy for advanced transitional cell carcinoma

Between May 1986 and September 1990 a total of 43 patients with metastatic transitional cell carcinoma (TCC) of the urinary tract have been treated at our institution with combination chemotherapy (CMV) consisting of cisplatin 100 mg m-2 i.v. day 2; methotrexate 30 mg m-2 i.v. days 1.8; and vinblastine 4 mg m-2 i.v. days 1.8. Chemotherapy was recycled on day 22 and continued for a maximum of six cycles in responding patients. Of 33 patients with measurable disease 8 (24%) achieved a complete remission (CR). The median survival for patients achieving a CR was 13 months (range 5-29+) whilst the median survival for all 43 patients was 7 months (range 1-29+). Only three patients are still alive--two are disease free. More effective and/or less toxic chemotherapy regimens are needed for the treatment of patients with metastatic TCC.

Involved field radiotherapy or chemotherapy in the management of stage I nodal intermediate grade non-Hodgkin's lymphoma

Early stage intermediate grade non-Hodgkin's lymphoma (NHL) is frequently treated with chemotherapy alone or in conjunction with radiotherapy. We have managed clinical Stage I nodal, intermediate grade NHL with involved field radiotherapy alone for non-bulky (less than 5 cm post-surgery) disease or combination chemotherapy alone for more bulky disease. Forty-three patients were treated between 1978 and 1989. Of the 30 patients with non-bulky disease treated with radiotherapy, 29 (97%) achieved complete remission (CR). Thirteen (42%) patients relapsed after radiotherapy and ten of these achieved a further CR (durable in eight) following salvage chemotherapy. Eleven patients with bulky disease received combination chemotherapy with nine (82%) attaining CR (durable in eight). Two patients with bulky disease received radiotherapy-both achieved CR, but have relapsed and died of lymphoma. Overall actuarial 5 year survival for the total group is 77% with a median follow-up of 30 months (range 3-119 months). The 5 year actuarial survival for the 30 patients with non-bulky disease treated with radiotherapy is 86% at a median follow-up of 39 months (range 8-119 months). The 4 year actuarial survival of the 11 patients treated with chemotherapy is 60% with a median follow-up of 25 months (range 3-55 months). We conclude that involved field radiotherapy alone is efficacious for clinical stage I patients with non-bulky nodal intermediate grade NHL and that patients relapsing after radiotherapy are adequately salvaged by chemotherapy. Patients with bulky disease have an inferior survival and should receive combination chemotherapy.

Non-Hodgkin's lymphoma arising in skeletal muscle

Four patients with non-Hodgkin's lymphoma who presented with clinical enlargement of muscle are reported. In three patients the only site of disease was muscle. Two patients with involvement of the paraspinal muscles demonstrated neurological complications due to spinal nerve root entrapment. A review of the literature emphasises the rarity of primary muscle lymphoma and suggests that disease arising at this site may confer a poor prognosis.

Intranasal amphotericin B reduces the frequency of invasive aspergillosis in neutropenic patients

PURPOSE

To retrospectively study the prophylaxis of invasive aspergillosis in neutropenic patients and to relate the frequency of this fungal disease to any causal or modifying factors that could be identified.

PATIENTS AND METHODS

Between 1977 and 1988, 130 patients underwent 158 intensive treatment episodes to control acute leukemia, lymphoma, and aplastic anemia, and the frequency of complicating aspergillus infection was determined.

RESULTS

Proven invasive aspergillus infections occurred in 22 cases, 12 of which were fatal. Invasive aspergillosis was suspected in a further 16 cases and all these patients recovered with amphotericin B treatment. Colonization by Aspergillus in the absence of clinically significant infection was seen in 31 treatment episodes. Invasive aspergillosis involved mainly the upper and lower respiratory tract and skin. Control of the infection was closely related to the control of the underlying disease, with subsequent return of normal marrow function and resolution of neutropenia. The incidence of aspergillus infection has decreased dramatically since 1985, most probably due to the introduction of intranasal amphotericin B. This occurred despite the persistence of aspergillus spores in the hematology ward air during the 1986 to 1988 period.

CONCLUSION

Intranasal aerosolized amphotericin B may protect against invasive aspergillosis, even when neutropenic patients are cared for in conventional wards without HEPA filtration.

The growing teratoma syndrome

Thirteen patients with metastatic non-seminomatous germ cell tumours and enlarging metastases consisting of teratoma differentiated only were identified. Patients were managed with surgical resection soon after the growing lesions were documented. Surgical morbidity was minimal and 12 patients are alive (10 are disease-free) at a median follow-up of 28 months.

Life-threatening airway obstruction at the presentation of Hodgkin's disease

Mediastinal involvement from Hodgkin's disease is common. Significant symptoms resulting from disease at this site are less common and only rarely does severe airway obstruction occur. The authors report six cases of Hodgkin's disease in which life-threatening airway obstruction was a major feature of the clinical presentation and early clinical course. The literature describing this complication is reviewed. General anesthesia with endobronchial intubation should be avoided if at all possible in patients with airway obstruction and alternative methods of diagnosis and management are discussed.

Cerebrospinal fluid B2-microglobulin levels in meningeal involvement by malignancy

Cerebrospinal fluid (CSF) and serum B2-microglobulin (B2m) levels were measured prospectively in 63 patients with hematological malignancies and 14 patients with solid tumours to evaluate the correlation between elevated levels and malignant infiltration of meninges. Serial CSF B2-m levels were also measured in 18 patients who received prophylactic intrathecal cytotoxic treatment. CSF B2-m levels were significantly higher in patients with central nervous system (CNS) involvement than in those without (p less than 0.001). A CSF B2-m level greater than 1.80 mg/L was closely associated with CNS disease (specificity 96%, sensitivity 76%) and CNS infiltration was also likely when the CSF B2-m level exceeded a simultaneously drawn serum level (specificity 98%, sensitivity 46%). Intrathecal methotrexate prophylaxis resulted in a consistent and significant rise in CSF B2-m levels with an average increase of 96% during a course of intrathecal injections. These results suggest that CSF B2-m levels may not be helpful for predicting early CNS relapse in these patients. However the CSF B2-m level and the corresponding serum B2-m level is a useful adjunct to the cytological diagnosis of CNS involvement by malignancy at presentation. Its value in predicting early CNS relapse and documenting response to CNS treatment requires further clarification.

A risk factor for relapse in Hodgkin's disease: female gender?

A retrospective study of 163 patients with Hodgkin's disease treated between 1969 and 1987 was performed to identify adverse prognostic factors. One hundred and thirty-five patients (83 per cent) attained a complete remission and 42 (31 per cent) of these have relapsed (median follow-up--43 months). Using multivariate analysis, no independent factors predicted for the event of relapse. However, analysis of disease-free survival revealed that females fared significantly worse than males (p less than 0.05) and this was independent of other prognostic variables. Female sex has not been recognized as an independent prognostic factor predictive of inferior survival and inferior disease-free survival.

Individualised aminoglycoside dosage based on pharmacokinetic analysis is superior to dosage based on physician intuition at achieving target plasma drug concentrations

1. A prospective randomised trial was conducted to compare aminoglycoside dose prediction based on individually measured pharmacokinetic data, with dosage based on physician intuition. 2. After 2 days of therapy more patients in the pharmacokinetic group had achieved both peak (6-10 mg 1(-1] and trough (1-2 mg 1(-1] target plasma concentrations (P = 0.007), peaks alone (P = 0.01) and troughs alone (P = 0.01). Their mean (s.e. mean) peak concentration was 6.49 +/- 0.39 mg 1(-1) compared with 4.27 +/- 0.52 mg 1(-1) in the control group (P = 0.001), with trough concentrations of 1.44 +/- 0.22 mg 1(-1) and 0.94 +/- 0.21 mg 1(-1) respectively (P = 0.054). 3. After 5 days of therapy, peak and trough concentrations were still significantly higher in the pharmacokinetic group despite empirical dose adjustment (P = 0.01 and P = 0.013 respectively). 4. The mean (s.e. mean) daily dose of aminoglycoside was higher in the computer group (312 +/- 17 mg vs 203 +/- 13 mg, P = 0.001). 5. These findings suggest that dose estimation based on measured pharmacokinetic parameters is superior at achieving target plasma drug concentrations.

Circadian pharmacokinetics of methotrexate

Six patients with intermediate- and high-grade non-Hodgkin's lymphoma were treated with 400 mg/m2 i.v. methotrexate (MTX) at 0600 and 1800 hours. Despite evidence of circadian rhythms in renal function, the pharmacokinetics of total and free serum MTX showed no significant difference between these two times. The marked two-fold circadian variation in MTX pharmacokinetics previously reported in rats was not observed in these patients.

The role of chemotherapy in malaria control through primary health care: constraints and future prospects

In the context of the malaria situation in tropical Africa, there continues to be an urgent need to make available as widely as possible the treatment of malaria cases and malaria prophylaxis. The current effort to establish community-based primary health care facilities provides an opportunity for application of these measures in wide areas of this region. If successful, the contribution to reducing morbidity and mortality would be substantial. Despite the results of previous studies on the delivery of malaria chemotherapy through primary health care channels, much more information is needed, and careful evaluation of all such programmes is highly important.There is a continuing need for expert guidance to determine the most appropriate and most effective patterns of drug use under a variety of circumstances. The status of antimalarial drug efficacy is not in any way static, so that constant re-evaluation of drug response, drug acceptance, significant side-effects, and alternative compounds is needed.

The seroepidemiology of malaria in Middle America. V. Antibody responses in an indicator population from an endemic area with attack phase antimalaria activities

Serologic assessment was carried out in a sample of the population living in an area endemic for malaria in which control measures were being applied. The study area was in El Salvador, Central America, and antimalarial activities consisted of the residual application of the pesticide, propoxur, and drug distribution through a combination of active and passive case detection. Indirect fluorescent antibody (IFA) responses to Plasmodium vivax and P. falciparum antigens were determined on four occasions, at approximately 6-month intervals. The study population consisted of one resident from each of 268 widely distributed houses. Each person was treated with a curative course of chloroquine and primaquine at the beginning of the investigation. An increase in the proportion of positive IFA responses (greater than or equal to 1:20) and an increasing number of serologic conversions (i.e., from negative to positive or a 2-fold increase in titer) during the course of the 18-month study confirmed continued transmission of malaria. The presence of parasites in some individuals without associated serologic changes is discussed.

Observations on two strains of plasmodium falciparum from Haiti in Aotus monkeys

Two strains of Plasmodium falciparum originating in Haiti were studied in the Aotus monkey. The Haitian I/CDC strain was first adapted to in vitro cultivation and subsequently inoculated into monkeys. The Haitian III/CDC strain was inoculated directly from a human patient into the Aotus monkey. The strains varied in their levels of pathogenicity to the animals. The Haitian I/CDC strain was highly virulent in six splenectomized animals; in one intact animal, the infection could be controlled but not eliminated with periodic doses of quinine and chloroquine. After subsequent splenectomy, the animal developed high parasitemias and died. No gametocytes developed in any of the Haitian I infections. The Haitian III strain was lethal to five of the 14 splenectomized monkeys inoculated, but some were able to control their infections without drug intervention. Gametocytes developed in all infections that persisted for an adequate length of time, and infections of mosquitoes were obtained both during the primary attack and the first recrudescence of the parasitemia. Of the mosquitoes tested, Anopheles freeborni was most susceptible to infection, followed by An. culicifacies, An. dirus, An. maculatus, and An. albimanus. The Haitian III strain was successfully transmitted to four other splenectomized Aotus monkeys via sporozoite inoculation using An. freeborni.

The enzyme-linked immunosorbent assay (ELISA) for malaria. III. Antibody response in documented Plasmodium falciparum infections

Serum specimens from patients in El Salvador, Central America, with slide-proven Plasmodium falciparum infections were examined for antibodies to P. falciparum using the enzyme-linked immunosorbent assay (ELISA) and the indirect fluorescent antibody (IFA) methods. Both serologic tests were positive in 78.1% of the 827 samples, both negative in 5.4%, the ELISA positive alone in 6.3%, and the IFA alone in 10.2%. Agreement between the serologic tests was better in the specimens with high positive titers (high IFA = high ELISA). Seropositivity rates and geometric mean titers were higher in the older (greater than or equal to 15 years) age groups for both ELISA and IFA; in such persons, the IFA was positive in 92% and the ELISA in 88%. The lowest seropositivity rates found by the ELISA were observed in children; 27.6% of 98 children less than or equal to 4 years of age were negative. A longer duration of infection as evidenced by the presence of gametocytes on the blood slide resulted in higher positivity rates by both ELISA and IFA. This phenomenon, particularly apparent in young children, supports the belief that the more important variable in determining the proportion of false negatives is previous malaria experience and not age. The results indicate that, while neither serologic test is appropriate as a diagnostic aid, both the ELISA and the IFA would be useful in epidemiologic investigations.

Anopheles pseudopunctipennis: laboratory maintenance and malaria susceptibility of a strain from El Salvador

The techniques involved in the establishment of a strain of Anopheles pseudopunctipennis pseudopunctipennis from El Salvador, Central America are presented. Results of experimental susceptibility studies using coindigenous strains of Plasmodium falciparum and P. vivax as well as P. vivax from Colombia indicated that this anopheline strain does not possess the biologic capability for malaria transmission. The usefulness of biological susceptibility data in establishing the vector status of anophelines, especially in areas with multiple species as potential vectors, is discussed.

Field evaluation of primaquine in the control of Plasmodium vivax

Two regimens of primaquine in combination with amodiaquine have been compared with amodiaquine alone in known cases of Plasmodium vivax in an endemic area of El Salvador, C.A. A 5-day regimen of primaquine, with dosages based on an adult dose of 15 mg per day, produced a substantial reduction in the numbers of patients experiencing renewed parasite activity and in the number of parasitemias experienced by the group during 9 mo of posttreatment observation, when compared with patients treated only with amodiaquine. A single dose regimen, based on an adult dose of 45 mg, similarly reduced the number of patients with renewed parasite activity and the number of parasitemias in the group. Those patients who experienced malaria attacks subsequent to treatment with either primaquine regimen experienced fewer such attacks than did those receiving amodiaquine alone. It is concluded that such primaquine regimens, which are more practicable for field use than the full 14-days curative regimen, are of value to both the patient and the community through the reduction of parasite episodes and the reduction of the source of mosquito infection for continuation of transmission.

The seroepidemiology of malaria in Middle America. III. Serologic assessment of localized Plasmodium falciparum epidemics

Epidemiologic studies were done in two localities, one in Panama and one in El Salvador, where outbreaks of Plasmodium falciparum malaria occurred. The indirect fluorescent antibody (IFA) method was helpful in defining the intensity of the outbreaks, the species of parasite involved, and, through parallel surveys of adjacent localities, the localized character of outbreaks. In Escobal, Panama 71 (34%) of 211 persons examined were IFA-positive for P. falciparum, although only 1 positive blood film was seen in this survey. In Jocomontique, El Salvador, 15 (28%) of 53 persons examined were IFA-positive for P. falciparum; 6 persons were parasite-positive. In the Panama study a number of children with positive IFA titers at the time of the epidemic had reverted to negative 6 months later. This lability of titers, in children, probably resulting from very early treatment of their first infection and, thus, a very brief exposure to the parasite antigen, suggests the need for caution in interpreting such negative serologic findings. Serologic studies provide valuable information in malaria epidemics, but must be interpreted in association with other known epidemiologic factors in the area concerned.

The seroepidemiology of malaria in Middle America. II. Studies on the Pacific coast of Costa Rica

Serologic studies for malaria using the indirect fluorescent antibody technique suggest that active transmission is either absent or very low in 6 villages on the Pacific side of Costa Rica. Positive titers (1:20 or higher) were seen in the under-15-year age group in three of the study localities, but only 5 such responses were encountered among 249 people examined in this age range. In the adults (15 years and over) from the same 3 villages there were 68 positive titers among 161 examined. There were 43 positive responses in 189 adults from the remaining 3 villages where none of 307 persons under 15 years of age showed a titer of 1:20 or higher to any of the 3 malaria antigens tested (Plasmodium falciparum, P. vivax and P. malariae). These data suggest that the positive responses in the latter villages are more likely to be associated with old or imported cases than with current local transmission. Serologic responses of 1:80 or higher to the P. falciparum antigen suggested the continued presence of this parasite in the population in spite of the paucity of positive blood smears with this species in recent years. Positive titers with the P. malariae antigen suggest that this parasite is probably still present in the area. Such serologic studies help to indicate areas where malaria transmission is active and provide information on parasite reservoirs in particular populations.

Application of the indirect fluorescent antibody method in a study of malaria endemicity in Mato Grosso, Brazil

Four surveys of malaria endemicity were conducted in the Cuiabá Sector of Mato Grosso State, Brazil, at 6-month intervals during the period April 1970 to September 1971; during April 1970 a survey was also conducted in the Campo Grande Sector. Over 4,000 dual specimens--blood films for parasite diagnosis and filter paper blood spots for determination of fluorescent antibody (IFA) response--were collected from the general population, including school populations whenever possible. Parasitologic examinations yielded positivity rates ranging from 0.8 to 2.3%. In the Cuiabá Sector, sero-positives (larger than or equal to 1:20) ranged from 9.3 to 13.6%; in the survey in the Campo Grande Sector only 4.3% of the specimens were positive. There was an expected increase in IFA response with age in both the proportion of positives and mean maximum titers. In the Cuiabá surveys 75 to 91% of the maximum positive responses were to the Plasmodium falciparum antigen, while in Campo Grande only 46% of the maximum titers were for P. falciparum. The wide differences in malaria endemicity observed within the Cuiabá Secctor were attributed to differences in climate, geography, and degree of development of the several regions. A study of surveillance reports from 1966 through the survey dates revealed that the high rates of infection seen often resulted from detection activities in the larger cities and probably represented cases imported from endemic areas to the north and west. In order to interpret accurately the endemicity of malaria in an area and, thus, determine the necessity for introduction or continuation of control measures, thorough epidemiologic studies are necessary. The addition of a serologic method to normal surveillance can increase the accuracy of interpretation.

Epidemiological significance of repeated infections with homologous and heterologous strains and species of Plasmodium

During many years of experience with the use of induced malaria for the therapy of neurosyphilis, it has been possible to observe the course of malarial infections in patients with known previous history of infection by the same and different strains and species of Plasmodium. This report presents the effect of prior infection on subsequent infection in regard to immune response of the host, clinical symptoms, parasitaemia, transmissibility and chemotherapeutic measures. These studies have shown that in no case was it impossible to induce additional infections in patients. However, in all homologous-species reinoculations, there were significant modifications of the infections, which were enhanced if both exposures were to the same strain. Variable results (ranging from no apparent effect to a fairly substantial modification) were seen after reinoculation of patients with a heterologous species of Plasmodium.The use of immunofluorescent methods may provide a clearer understanding of the mechanism of partial immunity as it affects reinfection. The relationship of this partial immunity to the epidemiology and chemotherapy of the disease in endemic areas is of importance, in that these infections in semi-immune persons provide a continuing and unapparent source of reinfection of the community.