Repatriation of a historical North Atlantic right whale habitat during an era of rapid climate change.

Climate change is affecting species distributions in space and time. In the Gulf of Maine, one of the fastest-warming marine regions on Earth, rapid warming has caused prey-related changes in the distribution of the critically endangered North Atlantic right whale (Eubalaena glacialis). Concurrently, right whales have returned to historically important areas such as southern New England shelf waters, an area known to have been a whaling ground. We compared aerial survey data from two time periods (2013-2015; 2017-2019) to assess trends in right whale abundance in the region during winter and spring. Using distance sampling techniques, we chose a hazard rate key function to model right whale detections and used seasonal encounter rates to estimate abundance. The mean log of abundance increased by 1.40 annually between 2013 and 2019 (p = 0.004), and the mean number of individuals detected per year increased by 2.23 annually between 2013 and 2019 (R2 = 0.69, p = 0.001). These results demonstrate the current importance of this habitat and suggest that management options must continually evolve as right whales repatriate historical habitats and potentially expand to new habitats as they adapt to climate change.

Characterization of large basking shark Cetorhinus maximus aggregations in the western North Atlantic Ocean.

Cetorhinus maximus aggregations recorded during extensive aerial survey efforts off the north-eastern United States between 1980 and 2013 included aggregations centring on sightings with group sizes of at least 30 individuals. These aggregations occurred in summer and autumn months and included aggregation sizes of up to 1398 individuals, the largest aggregation ever reported for this species. The aggregations were associated with sea surface temperatures of 13-24° C and chlorophyll-a concentrations of 0·4-2·6 mg m-3 and during one aggregation, a high abundance of zooplankton prey was present. Photogrammetric tools allowed for the estimation of total body lengths ranging between 4 and 8 m. Characterization of these events provides new insight into the potential biological function of large aggregations in this species.

Safety and efficacy of outpatient parenteral antibiotic therapy in an academic infectious disease clinic.

WHAT IS KNOWN AND OBJECTIVE: Outpatient parenteral therapy (OPAT) has become a safe and effective modality for patients requiring intravenous or prolonged antimicrobial therapy since the 1970s. It is being increasingly utilized in various settings; however, studies evaluating the safety and efficacy of clinic-based OPAT are limited. Since 2012, patients being considered for OPAT have required an infectious disease (ID) consultation at our institution. Candidates receiving once-daily antimicrobials who were ineligible for home infusion or nursing home placement as determined by their insurance companies and those who preferred the clinic over nursing home or home infusion were referred to the ID clinic. This study assessed the safety and outcome of patients receiving OPAT in an academic inner-city ID clinic in Detroit, Michigan. METHODS: This was a retrospective cross-sectional study of electronic medical records of patients, identified through clinic records, who received at least 2 days of OPAT from December 2012 to December 2015. Demographics, types of infections, antimicrobial regimen used, adverse events and outcome were evaluated. RESULTS: A total of 122 cases were identified during the study period. Mean age was 62 years with 55% male; 102 (84%) of 122 patients had peripherally inserted central catheter (PICC). Fifty-five per cent of patients participated in the clinic-based OPAT programme for insurance reasons, and 43% preferred the clinic over nursing home or home infusion. The most common infections were bone and joint (36%), followed by skin and soft tissue (18%) and urinary tract infections (12%). Ertapenem (44%) and daptomycin (41%) alone or in combination were used most frequently with 40% of patients receiving at least 4 weeks of treatment. Thirteen patients (11%) experienced one or more adverse drug events on daptomycin and/or ertapenem; of these, nine (69%) patients were receiving daptomycin monotherapy. Gastrointestinal symptoms (29%), cramping and myalgias (29%) and asymptomatic creatine phosphokinase (CPK) elevation (24%) were the most common adverse events. Three (3%) of 102 patients had PICC-related complications. Fourteen (88%) of 16 patients with adverse events or PICC-related complications required changing or stopping antibiotics; two (2%) had infection-related readmission. Conversely, 113 (93%) of 122 patients who completed treatment were considered cured and none had treatment failure at the end of 30 days of treatment. No patients died as a result of treatment or infection-related complications. WHAT IS NEW AND CONCLUSION: Outpatient parenteral therapy in our academic ID clinic was a safe and effective alternative to home infusion or skilled nursing facilities for patients requiring long-term antibiotics with few adverse events and complications.

PROX1 is a novel pathway-specific prognostic biomarker for high-grade astrocytomas; results from independent glioblastoma cohorts stratified by age and IDH mutation status.

PROX1 is a transcription factor with an essential role in embryonic development and determination of cell fate. In addition, PROX1 has been ascribed suppressive as well as oncogenic roles in several human cancers, including brain tumors. In this study we explored the correlation between PROX1 expression and patient survival in high-grade astrocytomas. For this purpose, we analyzed protein expression in tissue microarrays of tumor samples stratified by patient age and IDH mutation status. We initially screened 86 unselected high-grade astrocytomas, followed by 174 IDH1-R132H1 immunonegative glioblastomas derived from patients aged 60 years and older enrolled in the Nordic phase III trial of elderly patients with newly diagnosed glioblastoma. Representing the younger population of glioblastomas, we studied 80 IDH-wildtype glioblastomas from patients aged 18-60 years. There was no correlation between PROX1 protein and survival for patients with primary glioblastomas included in these cohorts. In contrast, high expression of PROX1 protein predicted shorter survival in the group of patients with IDH-mutant anaplastic astrocytomas and secondary glioblastomas. The prognostic impact of PROX1 in IDH-mutant 1p19q non-codeleted high-grade astrocytomas, as well as the negative findings in primary glioblastomas, was corroborated by gene expression data extracted from the Cancer Genome Atlas. We conclude that PROX1 is a new prognostic biomarker for 1p19q non-codeleted high-grade astrocytomas that have progressed from pre-existing low-grade tumors and harbor IDH mutations.

Extension of diffuse low-grade gliomas beyond radiological borders as shown by the coregistration of histopathological and magnetic resonance imaging data.

OBJECTIVE Magnetic resonance imaging tends to underestimate the extent of diffuse low-grade gliomas (DLGGs). With the aim of studying the presence of tumor cells outside the radiological border, the authors developed a method of correlating MRI findings with histological data in patients with suspected DLGGs in whom en bloc resections were performed. METHODS Five patients with suspected DLGG suitable for en bloc resection were recruited from an ongoing prospective study. Sections of the entire tumor were immunostained with antibodies against mutated IDH1 protein (IDH1-R132H). Magnetic resonance images were coregistered with corresponding IDH1 images. The growth pattern of tumor cells in white and gray matter was assessed in comparison with signal changes on corresponding MRI slices. RESULTS Neuropathological assessment revealed DLGG in 4 patients and progression to WHO Grade III glioma in 1 patient. The tumor core consisted of a high density of IDH1-R132H-positive tumor cells and was located in both gray and white matter. Tumor cells infiltrated along the peripheral fibers of the white matter tracts. In all cases, tumor cells were found outside the radiological tumor border delineated on T2-FLAIR MRI sequences. CONCLUSIONS The authors present a new method for the coregistration of histological and radiological characteristics of en bloc-removed infiltrative brain tumors that discloses tumor invasion at the radiological tumor borders. This technique can be applied to evaluate the sensitivity of alternative imaging methods to detect scattered tumor cells at tumor borders. Accurate methods for detection of infiltrative tumor cells will improve the possibility of performing radical tumor resection. In future studies, the method could also be used for in vivo studies of tumor invasion.

An Open Access future? Report from the eurocancercoms project.

In March 2011, as part of the background research to the FP7 Eurocancercoms project, the European Association for Cancer Research (EACR) conducted an online survey of its members working in Europe to discover their experiences of and attitudes to the issues surrounding academic publishing and Open Access. This paper presents the results from this survey and compares them to the results from a much larger survey on the same topic from the Study of Open Access Publishing (SOAP). The responses from both surveys show very positive attitudes to the Open Access publishing route; perhaps the most challenging statistic from the EACR survey is that 88% of respondents believe that publicly funded research should be made available to be read and used without access barriersAs a conclusion and invitation to further discussion, this paper also contributes to the debate around subscription and Open Access publishing, supporting the case for accelerating the progress towards Open Access publishing of cancer research articles as a particularly supportive way of assisting all researchers to make unhindered progress with their work.

Mass vaccination: solutions in the skin.

The skin is populated with Langerhans cells, thought to be efficient, potent antigen-presenting cells, that are capable of inducing protective immunity by targeting antigen delivery to the skin. Delivery to the skin may be accomplished by active delivery such as intradermal injection, use of patches or a combination of a universal adjuvant patch with injections. The robust immunity induced by skin targeting can lead to dose sparing, novel vaccines and immune enhancement in populations with poorly responsive immune systems, such as the elderly. Vaccine delivery with patches (transcutaneous immunization), may allow self-administration, ambient temperature stabilization and ease of storage for stockpiling, leading to a new level of efficient vaccine distribution in times of crisis such as a bioterror event or pandemic influenza outbreak. The use of an adjuvant (immunostimulant) patch with injected vaccines has been shown in clinical studies to enhance the immune response to an injected vaccine. This can be used for dose sparing in pandemic influenza vaccines in critically short supply or immune enhancement for poor responders to flu vaccines such as the elderly. Transcutaneous immunization offers a unique safety profile, as adjuvants are sequestered in the skin and only delivered systemically by Langerhans cells. This results in an excellent safety profile and allows use of extremely potent adjuvants. The combination of the skin immune system, safe use of potent adjuvants and ease of delivery suggests that skin delivery of vaccines can address multiple unmet needs for mass vaccination scenarios.

Efficacies of vesicular and free sodium stibogluconate formulations against clinical isolates of Leishmania donovani.

In this study, the in vitro and in vivo efficacies of free sodium stibogluconate (SSG) and a nonionic surfactant vesicular formulation of SSG (SSG-NIV) against a laboratory strain of Leishmania donovani (MHOM/ET/67:LV82) and different clinical isolates of L. donovani were determined. Treatment with SSG-NIV was more effective against intramacrophage amastigotes than treatment with SSG. In vivo murine studies showed that there was interstrain variability in the infectivity of the different L. donovani strains, with two of the strains (20001 and 20003) giving low parasite burdens. In addition, interstrain variability in the antileishmanial efficacy of SSG in a single dose containing 300 mg of Sb(V)/kg of body weight was observed. This dose of free drug either caused a >97% reduction in liver parasite burdens or had no significant effect on parasite burdens compared with the result with the respective control. In some instances, treatment with this free SSG dose also caused a significant reduction in spleen (strain 20006) or bone marrow (strains 20001 and 20009) parasite burdens. Treatment with SSG-NIV was more effective than that with SSG against all of the strains tested. In SSG-responsive strains, the reduction in liver parasite burdens by SSG-NIV treatment was similar to that caused by free SSG. In SSG-nonresponsive strains, SSG-NIV treatment caused at least a 95% reduction in liver parasite burdens. Overall, these results indicate that the use of a vesicular formulation of SSG is likely to increase its clinical efficacy against visceral leishmaniasis.

Resistance to treatment in Kala-azar: speciation of isolates from northeast India.

Kala-azar in India is becoming increasingly difficult to treat, which may be due to the presence of species other than Leishmania donovani; Leishmania tropica was reported to cause the same clinical syndrome in the area. Over the past 3 years, we have collected samples from 241 patients with visceral leishmaniasis from across the region. Of the 189 isolates that grew on diphasic medium, 159 were successfully transferred to liquid medium for typing. Clinically, 80% of these were resistant to antimony. Lipophosphoglycan-specific monoclonal antibodies were used to distinguish the 2 species by agglutination of promastigotes; all 159 were shown to be L. donovani. Eighty-three isolates were confirmed to be L. donovani by isoenzyme analysis, by amplification of kinetoplast DNA, or both, in comparison with multiple reference strains; none were L. tropica. Thus, the rising incidence of clinical resistance to treatment is unlikely to be due to a different species causing kala-azar in north Bihar.

Immunogenicity of well-characterized synthetic Plasmodium falciparum multiple antigen peptide conjugates.

Given the emerging difficulties with malaria drug resistance and vector control, as well as the persistent lack of an effective vaccine, new malaria vaccine development strategies are needed. We used a novel methodology to synthesize and fully characterize multiple antigen peptide (MAP) conjugates containing protective epitopes from Plasmodium falciparum and evaluated their immunogenicity in four different strains of mice. A di-epitope MAP (T3-T1) containing two T-cell epitopes of liver stage antigen-1 (LSA-1), a di-epitope MAP containing T-cell epitopes from LSA-1 and from merozoite surface protein-1, and a tri-epitope MAP (T3-CS-T1) containing T3-T1 and a potent B-cell epitope from the circumsporozoite protein central repeat region were tested in this study. Mice of all four strains produced peptide-specific antibodies; however, the magnitude of the humoral response indicated strong genetic restriction between the different strains of mice. Anti-MAP antibodies recognized stage-specific proteins on the malaria parasites in an immunofluorescence assay. In addition, serum from hybrid BALB/cJ x A/J CAF1 mice that had been immunized with the tri-epitope MAP T3-CS-T1 successfully inhibited the malaria sporozoite invasion of hepatoma cells in vitro. Spleen cells from immunized mice also showed a genetically restricted cellular immune response when stimulated with the immunogen in vitro. This study indicates that well-characterized MAPs combining solid-phase synthesis and conjugation chemistries are potent immunogens and that this approach can be utilized for the development of subunit vaccines.

Severe nutritional deficiencies in toddlers resulting from health food milk alternatives.

It is widely appreciated that health food beverages are not appropriate for infants. Because of continued growth, children beyond infancy remain susceptible to nutritional disorders. We report on 2 cases of severe nutritional deficiency caused by consumption of health food beverages. In both cases, the parents were well-educated, appeared conscientious, and their children received regular medical care. Diagnoses were delayed by a low index of suspicion. In addition, nutritional deficiencies are uncommon in the United States and as a result, US physicians may be unfamiliar with their clinical features. Case 1, a 22-month-old male child, was admitted with severe kwashiorkor. He was breastfed until 13 months of age. Because of a history of chronic eczema and perceived milk intolerance, he was started on a rice beverage after weaning. On average, he consumed 1.5 L of this drink daily. Intake of solid foods was very poor. As this rice beverage, which was fallaciously referred to as rice milk, is extremely low in protein content, the resulting daily protein intake of 0.3 g/kg/day was only 25% of the recommended dietary allowance. In contrast, caloric intake was 72% of the recommended energy intake, so the dietary protein to energy ratio was very low. A photograph of the patient after admission illustrates the typical features of kwashiorkor: generalized edema, hyperpigmented and hypopigmented skin lesions, abdominal distention, irritability, and thin, sparse hair. Because of fluid retention, the weight was on the 10th percentile and he had a rotund sugar baby appearance. Laboratory evaluation was remarkable for a serum albumin of 1.0 g/dL (10 g/L), urea nitrogen <0.5 mg/dL (<0.2 mmol/L), and a normocytic anemia with marked anisocytosis. Evaluation for other causes of hypoalbuminemia was negative. Therapy for kwashiorkor was instituted, including gradual refeeding, initially via a nasogastric tube because of severe anorexia. Supplements of potassium, phosphorus, multivitamins, zinc, and folic acid were provided. The patient responded dramatically to refeeding with a rising serum albumin and total resolution of the edema within 3 weeks. At follow-up 1 year later he continued to do well on a regular diet supplemented with a milk-based pediatric nutritional supplement. The mortality of kwashiorkor remains high, because of complications such as infection (kwashiorkor impairs cellular immune defenses) and electrolyte imbalances with ongoing diarrhea. Children in industrialized countries have developed kwashiorkor resulting from the use of a nondairy creamer as a milk alternative, but we were unable to find previous reports of kwashiorkor caused by a health food milk alternative. We suspect that cases have been overlooked. Case 2, a 17-month-old black male, was diagnosed with rickets. He was full-term at birth and was breastfed until 10 months of age, when he was weaned to a soy health food beverage, which was not fortified with vitamin D or calcium. Intake of solid foods was good, but included no animal products. Total daily caloric intake was 114% of the recommended dietary allowance. Dietary vitamin D intake was essentially absent because of the lack of vitamin D-fortified milk. The patient lived in a sunny, warm climate, but because of parental career demands, he had limited sun exposure. His dark complexion further reduced ultraviolet light-induced endogenous skin synthesis of vitamin D. The patient grew and developed normally until after his 9-month check-up, when he had an almost complete growth arrest of both height and weight. The parents reported regression in gross motor milestones. On admission the patient was unable to crawl or roll over. He could maintain a sitting position precariously when so placed. Conversely, his language, fine motor-adaptive, and personal-social skills were well-preserved. Generalized hypotonia, weakness, and decreased muscle bulk were present. Clinical features of rickets present on examination included: frontal bossing, an obvious rachitic rosary (photographed), genu varus, flaring of the wrists, and lumbar kyphoscoliosis. The serum alkaline phosphatase was markedly elevated (1879 U/L), phosphorus was low (1.7 mg/dL), and calcium was low normal (8.9 mg/dL). The 25-hydroxy-vitamin D level was low (7.7 pg/mL) and the parathyroid hormone level was markedly elevated (114 pg/mL). The published radiographs are diagnostic of advanced rickets, showing diffuse osteopenia, frayed metaphyses, widened epiphyseal plates, and a pathologic fracture of the ulna. The patient was treated with ergocalciferol and calcium supplements. The published growth chart demonstrates the dramatic response to therapy. Gross motor milestones were fully regained within 6 months. The prominent neuromuscular manifestations shown by this patient serve as a reminder that rickets should be considered in the differential diagnosis of motor delay. (ABSTRACT TRUNCATED)

Evaluation of covert video surveillance in the diagnosis of munchausen syndrome by proxy: lessons from 41 cases.

OBJECTIVE: In 1993, Children's Healthcare of Atlanta at Scottish Rite (formery Scottish Rite Children's Medical Center, Atlanta, GA) added facilities to perform inpatient covert video surveillance (CVS) of suspected cases of Munchausen syndrome by proxy (MSBP). Forty-one patients were monitored from 1993 to 1997. This study was performed to review our experience with these cases. How useful was video surveillance in making the diagnosis? What were the characteristics of families with children who were victims of MSBP? METHODOLOGY: Medical, social work, security, and administrative records of all children who underwent covert video monitoring at Children's Healthcare of Atlanta at Scottish Rite from 1993 through 1997 were reviewed retrospectively by a team of physicians, risk managers, and social workers. RESULTS: A diagnosis of MSBP was made in 23 of 41 patients monitored. CVS was required to make the diagnosis in 13 (56.1%) of these 23, and supportive of the diagnosis in 5 (21.7%) cases. In 4 patients, this surveillance was instrumental in establishing innocence of the parents. MSBP was more common in Caucasian patients than in other ethnic groups seen at our hospital. Fifty-five percent of mothers gave a history of health care work or study, and another 25% had previously worked in day care. Although many of caretakers fit the profile of MSBP, such as excessive familiarity with medical staff, eagerness for invasive medical testing, and history of health care work, these characteristics were not sensitive indicators of MSBP in our study. Even when present, they were not sufficiently compelling to make the diagnosis. CONCLUSIONS: CVS is required to make a definitive and timely diagnosis in most cases of MSBP. Without this medical diagnostic tool, many cases will go undetected, placing children at risk. All tertiary care children's hospitals should develop facilities to perform CVS in suspected cases.

Inhibition of interferon-gamma signaling by Leishmania donovani.

Leishmania infection causes marked down-regulation of interferon (IFN)-gamma-induced gene activity in macrophages, but the mechanism of the blockade has not been fully defined. The IFN-gamma signal transduction pathway was analyzed in Leishmania donovani-infected phorbol-differentiated U937 human promonocytic cells. IFN-gamma stimulation induced marked phosphorylation of its own receptor (IFN-gammaR)-alpha chain. Phosphorylation of the receptor subunit was significantly inhibited after 24 h of infection with the parasite, apparently because of decreased amounts of the receptor subunit. Formation of the IFN-gammaR complex, as assessed by tyrosine phosphorylation and association of Jak2, was strongly inhibited in cells infected for 24 h. Inhibition of the IFN-gammaR complex formation correlated with inhibition of STAT1alpha binding to the IFN-gamma response region. Pretreatment with purified parasite lipophosphoglycan before IFN-gamma stimulation had no effect on tyrosine phosphorylation. Thus, inhibition of tyrosine phosphorylation of the IFN-gammaR-alpha chain and subsequent signal transduction are most likely due to the decreased amount of IFN-gammaR-alpha protein after infection.

Possible role of autoimmunity to spermatozoa in idiopathic infertility of stallions.

Testicular degeneration is a major cause of subfertility in stallions, although an aetiological diagnosis cannot be made in most cases. In the present study, autoimmune testicular degeneration was induced and evaluated in stallions by immunizing stallions with their own spermatozoa mixed with an adjuvant. The factors evaluated included changes in semen quality and testicular histology. A large decrease in sperm number and quality was observed in response to sperm autoantigens. An ELISA test specific for antisperm antibodies was developed which enabled antibody titres in serum, seminal plasma and accessory sex organs to be measured. Serum antibodies were characterized as being specific for spermatozoa by absorption studies and western blotting. The data obtained and the tests developed in the present study provide a better understanding of the disease in subfertile breeding stallions and the ability to diagnose the disease using ELISA. The results of a clinical trial demonstrate that there is a higher incidence of antisperm antibodies in subfertile stallions compared with fertile stallions. The results of the present study indicate that autoimmunity to spermatozoa plays a role in idiopathic subfertility in stallions. A potentially useful method for tentative diagnosis of autoimmune testicular degeneration in subfertile stallions was also developed.

Is the Internet useful for clinical practice?

BACKGROUND: Internet use in dentistry is increasing. The authors surveyed dentists to determine how they are using the Internet to support patient care and how useful they perceive the Internet to be. MATERIALS AND METHODS: The authors sent a 25-question survey to 455 subscribers to the Internet Dental Forum, an Internet discussion list. Participants completed the survey through a Web page or by e-mail during an 18-day period in December 1998. The survey included questions about when they began using the Internet and their motivations for doing so, their positive and negative experiences, where they use the Internet and why, their use of information resources--including electronic information resources--and demographics. RESULTS: The authors received 314 surveys from 438 participants, a 72 percent response rate. Participants reported demographic characteristics similar to national averages and were highly computer-literate. Most considered the Internet essential for their practice and had increased their Internet use for professional reasons over time. Ninety-seven percent of respondents used the Internet at home, and 68 percent used it in the office. Only 5 percent used the Internet in the treatment area. The primary reason cited by participants for using the Internet was to keep up in general, followed by to answer patient-specific questions and to provide patient education. Reduction of professional isolation was one of the most frequently cited advantages of using the Internet. CONCLUSIONS: The authors found that some dentists use the Internet to support clinical practice and that it helped dentists adopt new techniques for patient treatment and obtain information on new materials or products. CLINICAL IMPLICATIONS: The Internet appears to support clinical practice mostly indirectly, by helping users keep up in general, rather than by answering specific clinical questions.

Protective immunity using recombinant human IL-12 and alum as adjuvants in a primate model of cutaneous leishmaniasis.

Protection from cutaneous leishmaniasis, a chronic ulcerating skin lesion affecting millions, has been achieved historically using live virulent preparations of the parasite. Killed or recombinant Ags that could be safer as vaccines generally require an adjuvant for induction of a strong Th1 response in murine models. Murine rIL-12 as an adjuvant with soluble Leishmania Ag has been shown to protect susceptible mice. We used 48 rhesus macaques to assess the safety, immunogenicity, and efficacy of a vaccine combining heat-killed Leishmania amazonensis with human rIL-12 (rhIL-12) and alum (aluminum hydroxide gel) as adjuvants. The single s.c. vaccination was found to be safe and immunogenic, although a small transient s.c. nodule developed at the site. Groups receiving rhIL-12 had an augmented in vitro Ag-specific IFN-gamma response after vaccination, as well as increased production of IgG. No increase in IL-4 or IL-10 was found in cell culture supernatants from either control or experimental groups. Delayed hypersensitivity reactions were not predictive of protection. Intradermal forehead challenge infection with 107 metacyclic L. amazonensis promastigotes at 4 wk demonstrated protective immunity in all 12 monkeys receiving 2 microgram rhIL-12 with alum and Ag. Partial efficacy was seen with lower doses of rhIL-12 and in groups lacking either adjuvant. Thus, a single dose vaccine with killed Ag using rhIL-12 and alum as adjuvants was safe and fully effective in this primate model of cutaneous leishmaniasis. This study extends the murine data to primates, and provides a basis for further human trials.

Evidence that the high incidence of treatment failures in Indian kala-azar is due to the emergence of antimony-resistant strains of Leishmania donovani.

The possibility that the high frequency of treatment failures in Indian kala-azar might be due to infection with antimony-resistant strains of Leishmania donovani has not been experimentally addressed. L. donovani isolates were obtained from splenic aspiration smears of 24 patients in Bihar, India, who either did not respond (15) or did respond (9) to 1 or more full courses of treatment with sodium antimony gluconate (SAG). A strong correlation (P<.001) between clinical response and SAG sensitivity in vitro was observed only when strains were assayed as intracellular amastigotes: responsive isolates ED50=2.4+/-2.6, ED90=6.4+/-7.8 microgram SAG/mL; unresponsive isolates ED50=7.4+/-3.7 microgram SAG/mL, ED90=29.1+/-11.1 SAG/mL. No correlation with clinical response was found by use of extracellular promastigotes (ED50=48+/-22 vs. 52+/-29 microgram/mL). The emergence of antimony-resistant L. donovani strains appears to be a cause of treatment failures in India.