Effect of Particle Formation Process on Characteristics and Aerosol Performance of Respirable Protein Powders.

Pulmonary delivery of biopharmaceuticals may enable targeted local therapeutic effect and noninvasive systemic administration. Dry powder inhaler (DPI) delivery is an established patient-friendly approach for delivering large molecules to the lungs; however, the complexities of balancing protein stability with aerosol performance require that the design space of biopharmaceutical DPI formulations is rigorously explored. Utilizing four rationally selected formulations obtained using identical atomization conditions, an extensive study of the effect of the particle formation process (spray drying or spray freeze-drying) on powder properties, aerosol performance, and protein stability was performed. Multiple linear regression analysis was used to understand the relationship between powder properties, device dispersion mechanism, and aerosol performance. Spray drying and spray freeze-drying, despite the same spraying conditions, produced powders with vastly different physical characteristics, though similar aerosol performance. The resulting regression model points to the significance of particle size, density, and surface properties on the resulting aerosol performance, with these factors weighing differently according to the device dispersion mechanism utilized (shear-based or impaction-based). The physical properties of the produced spray dried and spray freeze-dried powders have differing implications for long-term stability, which will be explored extensively in a future study.

Influence of Formulation Factors on the Aerosol Performance and Stability of Lysozyme Powders: a Systematic Approach.

With the growing interest in developing biologics for pulmonary delivery, systematic fast screening methods are needed for rapid development of formulations. Due to the labile nature of macromolecules, the development of stable, biologically active formulations with desired aerosol performance imposes several challenges both from a formulation and processing perspective. In this study, spray-freeze-drying was used to develop respirable protein powders. In order to systematically map the selected design space, lysozyme aqueous pre-formulations were prepared based on a constrained mixture design of experiment. The physicochemical properties of the resulting powders were characterized and the effects of formulation factors on aerosol performance and protein stability were systematically screened using a logic flow chart. Our results elucidated several relevant formulation attributes (density, total solid content, protein:sugars ratio) required to achieve a stable lysozyme powder with desirable characteristics for pulmonary delivery. A similar logical fast screening strategy could be used to delineate the appropriate design space for different types of proteins and guide the development of powders with pre-determined aerodynamic properties.

An overview on alcohol oxidases and their potential applications.

Alcohol oxidases (Alcohol: O2 Oxidoreductase; EC 1.1.3.x) are flavoenzymes that catalyze the oxidation of alcohols to the corresponding carbonyl compounds with a concomitant release of hydrogen peroxide. Based on substrate specificity, alcohol oxidases may be categorized broadly into four different groups namely, (a) short chain alcohol oxidase (SCAO), (b) long chain alcohol oxidase (LCAO), (c) aromatic alcohol oxidase (AAO), and (d) secondary alcohol oxidase (SAO). The sources reported for these enzymes are mostly limited to bacteria, yeast, fungi, plant, insect, and mollusks. However, the quantum of reports for each category of enzymes considerably varies across these sources. The enzymes belonging to SCAO and LCAO are intracellular in nature, whereas AAO and SAO are mostly secreted to the medium. SCAO and LCAO are invariably reported as multimeric proteins with very high holoenzyme molecular masses, but the molecular characteristics of these enzymes are yet to be clearly elucidated. One of the striking features of the alcohol oxidases that make them distinct from the widely known alcohol dehydrogenase is the avidly bound cofactor to the redox center of these enzymes that obviate the need to supplement cofactor during the catalytic reaction. These flavin-based redox enzymes have gained enormous importance in the development of various industrial processes and products primarily for developing biosensors and production of various industrially useful carbonyl compounds. The present review provides an overview on alcohol oxidases from different categories focusing research on these oxidases during the last decade along with their potential industrial applications.

Serum human telomerase reverse transcriptase: a novel biomarker for breast cancer diagnosis.

BACKGROUND: Telomerase is a ribonucleoprotein complex composed mainly of a reverse transcriptase catalytic subunit, telomerase reverse transcriptase (hTERT). Expression of hTERT confers telomerase activity, indicating that hTERT is the rate-limiting component of human telomerase. The aim of the present study was to investigate the diagnostic implications of hTERT in the serum of breast cancer patients. METHODS: The study was conducted on 159 breast cancer patients and 41 healthy volunteers as controls. The evaluation of hTERT, cancer antigen 15.3 and carcinoembryonic antigen were performed by enzyme-linked immunosorbent assay, and analysed for their correlation with the patient's clinicopathological features. RESULTS: 27 of 52 (51.9%) patients with stage I breast cancer, 31 of 40 (77.5%) with stage II and 30 of 34 (88.2%) patients with stage III exhibited elevated hTERT levels. Serum hTERT levels showed significantly higher mean values in patients with breast cancer than healthy individuals. The sensitivity and specificity of hTERT in cancer diagnosis was 68.9 and 83.3%, respectively, which is significantly higher than conventional markers. The expression of serum hTERT was significantly correlated with telomerase activity in breast cancer tissues. Pretreatment serum hTERT levels showed a significant correlation with clinical stage, while correlation with nodal status and tumor size were marginal and no correlation was found with family history and age. CONCLUSION: Serum hTERT is useful for diagnosing and assessing the clinical stage of breast cancer and is superior to conventional markers. Therefore, serum hTERT could have a potential application as a novel biomarker for breast cancer diagnosis.

Development, evaluation and validation of machine learning algorithms to detect atypical and asymptomatic presentations of Covid-19 in hospital practice.

BACKGROUND: Diagnostic methods for Covid-19 have improved, both in speed and availability. Because of atypical and asymptomatic carriage of the virus and nosocomial spread within institutions, timely diagnosis remains a challenge. Machine learning models trained on blood test results have shown promise in identifying cases of Covid-19. AIMS: To train and validate a machine learning model capable of differentiating Covid-19 positive from negative patients using routine blood tests and assess the model's accuracy against atypical and asymptomatic presentations. DESIGN AND METHODS: We conducted a retrospective analysis of medical admissions to our institution during March and April 2020. Participants were categorized into Covid-19 positive or negative groups based on clinical, radiological features or nasopharyngeal swab. A machine learning model was trained on laboratory parameters and validated for accuracy, sensitivity and specificity and externally validated at an unconnected establishment. RESULTS: An Ensemble Bagged Tree model was trained on data collected from 405 patients (212 Covid-19 positive) producing an accuracy of 81.79% (95% confidence interval (CI) 77.53-85.55%), the sensitivity of 85.85% (CI 80.42-90.24%) and specificity of 76.65% (CI 69.49-82.84%). Accuracy was preserved for atypical and asymptomatic subgroups. Using an external data set for 226 patients (141 Covid-19 positive) accuracy of 76.82% (CI 70.87-82.08%), sensitivity of 78.38% (CI 70.87-84.72%) and specificity of 74.12% (CI 63.48-83.01%) was achieved. CONCLUSION: A machine learning model using routine laboratory parameters can detect atypical and asymptomatic presentations of Covid-19 and might be an adjunct to existing screening measures.

A prospective study on COVID-19 convalescent plasma donor (CCP) recruitment strategies in a resource constrained blood centre.

Background and Objectives: The COVID-19 pandemic has spread across 87 million people with more than 1·8 million deaths in the world. As there is no definite treatment modality, the use of convalescent plasma has become increasingly popular worldwide. This study aimed to identify an appropriate strategy of donor recruitment and to evaluate the appropriateness of pre-set plasma donation guidelines. Material and Methods: In this prospective study conducted from May to September 2020, the donors were recruited under the following two circumstances: Group I, patients in the post-COVID-19 follow-up in the clinic, and Group II, patients recovered from COVID-19 recruited through mass and electronic media. A pre-set donor selection criteria and laboratory investigation was designed according to national and international guidelines. Approximately 500 ml of COVID-19 convalescent plasma (CCP) was collected from recovered individuals in each group by two different cell separators. The overall donor's attendance rate, deferral rate, adverse events and donor compliance was analysed and compared between the two groups. Results: There was a significant difference in attendance in relation to registration between the groups (P < 0·0001). Donor deferral was significantly higher in group II compared with group I. The single most frequent cause of donor deferral was low antibody index (P = 0·0001). The total donor adverse event rate in CCP donation was significantly lower compared with routine plateletpheresis procedures. The donor's compliance to blood centre's protocol was satisfactory in both the groups. Conclusion: Recruitment of patients in the post-COVID-19 follow-up in the clinic was more effective than the general recruitment through mass and electronic media for convalescence plasma donation in a resource-constrained blood centre.

Determination of glycemic index value of Naturo fruit bars.

AIM AND OBJECTIVE: The glycemic response to Naturo fruit bar that is commercially available in India was determined against a glucose sta dard in a non-blind, repeated measure, crossover design trial. METHODS: Eleven healthy subjects (mean age 37.3 (SD 5.5) years and mean BMI 213 (SD 36) kg/m2) were recruited to the study. Subjects were given Naturo fruit bar and a standard food (glucose), on separate occasions, each containing 50 grams carbohydrate. Blood glucose was determined after overnight fasting (0 hours) and at 30, 60, 90 and 120 min after the consumption of each test food. For Naturo fruit bar, the glycemic index (GI) value was calculated geometrically by expressing the incremental area under the blood glucose curve (iAUC) as a percentage of each subject's average iAUC for the standard food. RESULTS: The GI value of Naturo fruit bar was found to be 38.50. As per the Food and Agriculture Organization, GI cut-off values are as follows: low <55; medium 56-69 inclusive, high >70. Therefore Naturo fruit bar could be classified under low glycemic food/nutrient. CONCLUSION: Considering the widespread consumption of fruits/bars in India, this information is valuable for people who prefer to use low glycemic food which offer many beneficial effects because their consumption significantly reduces the GI of the diets of the Indian population.

Craniofacial features in Goldenhar syndrome.

Goldenhar syndrome also known as oculo-auriculo-vertebral syndrome was first reported by Dr Maurice Goldenhar in 1952. It is a rare disease entity characterized by craniofacial anomalies such as hypoplasia of the mandible and malar bones, microtia, and vertebral anomalies. The etiology of this disease still remains unclear and occurs as sporadic. This report presents goldenhar syndrome in a 12-year-old male patient.

Clinical manifestations of Ellis-van Creveld syndrome.

Ellis-van Creveld syndrome (EVC) is a chondro-ectodermal dysplasia characterized by short ribs, polydactyly, growth retardation and ectodermal and heart defects. It is a rare disease complex and very few cases have been reported in dental literature. This condition is inherited as an autosomal recessive trait with variable expression. The present case report describes EVC in a 7-year-old girl, with all the tetrad of cardinal features. We found a rare dental aberration in form; appearance of single conical roots in primary molars. The management of children with EVC is multidisciplinary, with consideration for the high incidence of cardiac defects in these patients.

Dosing considerations for inhaled biologics.

The number of biologics in the therapeutic development pipeline is increasing including those delivered though inhalation (Morales, 2017; Fathe, 2016). Biologics comprise a broad variety of complex macromolecules with unique physicochemical characteristics. These distinctive characteristics control their pharmacological mechanisms of action, stability, and ultimately affect their processing, formulation, and delivery requirements. This review systematically covers crucial aspects of biologic powders formulations and dry powder inhalers which need to be taken into consideration to establish the drug loading and the payload to be delivered to reach the desired clinical dose.

Interplay of pregnancy, lactation, and hyperthyroidism leading to severe osteoporosis in a young woman.

OBJECTIVE: To describe the case of a young woman who had severe osteoporosis due to the compounding effects of pregnancy, lactation, and hyperthyroidism and who had a presumed metastatic lesion in the lumbar spine. METHODS: We present the clinical, pathologic, radiologic, and laboratory findings and describe the clinical course of our patient. RESULTS: A 31-year-old Arabic woman was referred to the M. D. Anderson Cancer Center because of a lytic lesion in her lumbar spine, presumed to be metastatic deposits. She had a history of two consecutive pregnancies and intermittently treated hyperthyroidism. Our initial evaluation revealed that the patient had clinical and biochemical thyrotoxicosis, and we treated her with thionamides, corticosteroids, and radioiodine ablation. Radiologic studies disclosed a complex renal cyst that had increased uptake on a bone scan, which was highly suggestive of a primary malignant lesion. Ultimately, however, it proved benign on pathologic analysis after a left nephrectomy. Bone mineral density measurements identified severe osteoporosis (T-scores: lumbar spine, -3.3; right hip, -2.2; and left hip, -2.0), which had led to vertebral collapse and was misinterpreted as malignant metastatic disease. The bone mineral densities improved (+5 to +11% at the various sites) within 4 months after definitive treatment and cure of the hyperthyroidism. CONCLUSION: The effect of pregnancies and prolonged lactation, in the milieu of other risk factors for bone depletion such as hyperthyroidism, may cause severe osteoporosis in a young patient. The resulting osteoporosis may manifest as a lesion suggestive of malignant metastatic involvement.

Diet induced thermogenesis with oral & intravenous feeding in chronically undernourished human subjects.

The parasympathetic nervous system (PNS) has been shown to be important in the mediation of diet induced thermogenesis (DIT). Chronically energy deficient (CED) subjects have a high resting parasympathetic tone, which could lead to a greater than expected DIT. DIT was studied in chronically energy deficient adult men and healthy age-matched volunteers (6 controls, 7 CED subjects) with an isocaloric (600 kcal) meal given by the oral and intravenous (i.v.) routes on two consecutive days, on a crossover basis. The resting metabolic rate (RMR) and the DIT were measured over 6 h, along with cardiovascular, biochemical and anthropometric parameters. Anthropometrically (height, weight, fat free mass, body mass index, mid upper arm circumference and sum of skinfolds), the CED group differed significantly from the well-nourished control group. There were no significant differences between the two groups in the basal state for metabolic (RMR, oxygen consumption, respiratory quotient), cardiovascular [blood pressure (BP), heart rate, cardiac output], and biochemical (plasma glucose, insulin and norepinephrine) parameters. The CED group had a significantly higher DIT response for both meal types when compared to the controls, when expressed as an absolute value and as a percentage response. However, the response was not significant when corrected for the meal size and body weight. There were also no significant differences between the two meal types in each group for the metabolic, cardiovascular and biochemical parameters during the DIT period, although, in general, the oral meal gave a larger DIT response compared to the i.v. meal. Both groups predominantly oxidised fat during the fasted stage and switched to carbohydrate oxidation when fed. It appears that, the previously demonstrated higher tone in the PNS, does not make a significant contribution to the thermic response of a meal in these subjects.

Impact of visual instruction on oral hygiene status of children with hearing impairment.

BACKGROUND: Children with hearing impairment (CHI) have poor oral health and extensive unmet treatment needs. This could be attributed to their inability to cooperate with dental treatment and lack of oral health awareness due to communication barriers. AIM: The aim of this study was to verify the impact of visual instruction on oral hygiene status of CHI. STUDY DESIGN: Prospective triple blind interventional study. MATERIALS AND METHODS: Oral hygiene status of 372 institutionalized CHI aged 6-16 years, divided into study (180) and control groups (192) was evaluated using Loe and Silness Gingival index and Silness and Loe Plaque index. Motivation in the form of visual instruction was done in the study group every weekend for 12 weeks and control group was followed without motivation. Oral hygiene status was re-assessed and analyzed. STATISTICAL ANALYSIS: Paired t-test was used to compare the scores before and after the instructions. Unpaired t-test was used for intergroup comparison between the study and control groups. RESULTS: There was a significant mean reduction of plaque (0.37) and gingival scores (0.39) in the study group, but only marginal reduction of plaque (0.08) and gingival scores (0.1) observed in the control group. Significant gender and age variations were observed. CONCLUSION: Visual instruction was found to be an effective oral health education tool in CHI.

Small-angle neutron scattering study of a monoclonal antibody using free-energy constraints.

Monoclonal antibodies (mAbs) contain hinge-like regions that enable structural flexibility of globular domains that have a direct effect on biological function. A subclass of mAbs, IgG2, have several interchain disulfide bonds in the hinge region that could potentially limit structural flexibility of the globular domains and affect the overall configuration space available to the mAb. We have characterized human IgG2 mAb in solution via small-angle neutron scattering (SANS) and interpreted the scattering data using atomistic models. Molecular Monte Carlo combined with molecular dynamics simulations of a model mAb indicate that a wide range of structural configurations are plausible, spanning radius of gyration values from ∼39 to ∼55 Å. Structural ensembles and representative single structure solutions were derived by comparison of theoretical SANS profiles of mAb models to experimental SANS data. Additionally, molecular mechanical and solvation free-energy calculations were carried out on the ensemble of best-fitting mAb structures. The results of this study indicate that low-resolution techniques like small-angle scattering combined with atomistic molecular simulations with free-energy analysis may be helpful to determine the types of intramolecular interactions that influence function and could lead to deleterious changes to mAb structure. This methodology will be useful to analyze small-angle scattering data of many macromolecular systems.

Clinical evaluation of Root ZX II electronic apex locator in primary teeth.

AIM: To evaluate the accuracy of Root ZX II electronic apex locator (EAL) for root canal working length determination in primary teeth. METHODS: Forty primary maxillary incisor teeth were included in the study. Root ZX II EAL was used to determine the electronic working length (EL). The working length obtained with EAL was evaluated using digital radiography with the measuring file set to EL. The samples were categorised into three groups. Group 1 (acceptable): file tip 0-1mm short of the radiographic apex; Group 2 (short): file tip > 1mm short of the apex and Group 3 (long): file tip beyond the apex. Digital radiographic working length (RL) was derived by adjusting EL to the radiographic apex. The assigned calibrations were tabulated and statistically analysed. RESULTS: Group 1 included 28 out of 40 teeth indicating a clinical accuracy of 70%. Group 2 contained 10 (25%) teeth whereas group 3 had only 2 (5%) teeth. STATISTICS: Pearson correlation coefficient statistical analysis showed a high correlation (r = +0.82; p<0.001) among the groups. CONCLUSION: Root ZX II EAL can be used as a reliable device for obtaining root canal length in primary maxillary incisor teeth.

Evaluation of serum human telomerase reverse transcriptase as a novel marker for cervical cancer.

Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of human telomerase and its rate-limiting component. The purpose of the present study was to investigate the diagnostic value of hTERT in serum of cervical cancer patients. Preoperative values of hTERT, squamous cell carcinoma antigen (SCC-ag) and cancer antigen 125 (CA 125) were measured by enzyme-linked immunosorbent assay (ELISA) in 192 patients with squamous cell carcinoma or adenocarcinoma of the uterine cervix and 38 healthy controls. Elevated pretreatment levels of hTERT were identified in 80.2% of squamous cell carcinoma and 73.8% of adenocarcinoma patients. The expression of serum hTERT was correlated with telomerase activity in cancer tissues of both histological types. Pretreatment serum hTERT levels showed a significant correlation with clinical stage, tumor size and lymph node metastasis, but not with age. Serum hTERT measurement was found to be useful in the diagnosis and assessment of clinical stage of cervical cancer, and to be superior to the conventional tumor markers. Therefore, serum hTERT is a novel and readily available marker for cervical malignancies.

Viscoelastic characterization of high concentration antibody formulations using quartz crystal microbalance with dissipation monitoring.

With increasing protein concentrations, therapeutic protein formulations are increasingly demonstrating significant deviations from ideal dilute solution behavior due to protein-protein interactions. These interactions lead to unique biophysical challenges in the administration of biopharmaceuticals including high apparent viscosity and viscoelasticity as well as challenges in maintaining the physical stability of proteins in solution. Here, we describe a straightforward analytical method to calculate the complex modulus and viscosity of high concentration protein solutions from measurements made using quartz crystal microbalance with dissipation monitoring (QCM-D). Further, this methodology was used to investigate the dependence of the storage and loss moduli (G' and G'', respectively) of a humanized monoclonal antibody solution on solution pH. Unlike recent reports, the effect of protein deposition onto the surface of the quartz sensor crystal was measured and explicitly accounted for during analysis when determining the solution's complex modulus. It was found that the ratio G''/G' was significantly greater than unity for all solutions investigated, but demonstrated a distinct maximum at pH 5.5 indicating that the solution exhibited the greatest liquid-like behavior at this pH. In addition, measurements were made at higher frequencies, which were found to be more sensitive to the changes in pH than those made at lower frequencies. It was also found that the viscoelastic ratio was relatively insensitive to the frequency of measurement at lower pH, but showed greater dependence on frequency as pH increased. The characterization of the rheological properties of high concentration antibody solutions provides insight into protein-protein interactions, and the methodology presented here demonstrates a straightforward way to determine the viscoelastic properties using ultrasonic rheology without the drawbacks of numerical fitting.

A rare cause of an abdominal mass.

A 57-year-old male presented with right upper abdominal lump since 3 months. He was diagnosed to have a hepatic artery aneurysm. He was investigated thoroughly but no cause was found. He was subjected to endovascular embolisation of the aneurysm using endovascular coils. Subsequently the aneurysm was completely occluded. Hepatic artery aneurysms are very rare among all visceral aneurysms. We report this rare case of hepatic artery aneurysm presenting as an abdominal lump. This case highlights the importance of early diagnosis and management of this rare entity as a rupture may be catastrophic.

Relationship between rate of administration of electroconvulsive shocks and rate of learning in rats: implications for the practice of ECT.

Number of electroconvulsive therapy (ECT) treatments administered and severity of psychopathology confound the interpretation of clinical studies that address the relationship between the rate of administration of ECT and cognitive morbidity occasioned by the treatment. A preclinical study was therefore conducted to address the issue. Three groups (n = 8/group) of adult male Sprague-Dawley rats received six electroconvulsive shocks (ECS) in daily ECS, 3 ECS/week, and 2 ECS/week schedules; a fourth group (control; n = 8) received only sham ECS. From days 2 to 7 after the conclusion of the ECS/sham ECS course, the rats were monitored for learning on the Hebb-Williams complex maze. The control, 2 ECS/week, and 3 ECS/week groups showed significant learning by days 3, 5, and 7, respectively, while the daily ECS group showed no significant learning during the assessment period. This indicates that even when the cumulative effect of ECS on learning is controlled for, more frequent ECS is associated with slower learning. Extrapolating to clinical settings, it is suggested that wider spacing of ECT may lessen ECT-induced cognitive morbidity.

Severe osteopenia in a young boy with Kostmann's congenital neutropenia treated with granulocyte colony-stimulating factor: suggested therapeutic approach.

Kostmann's syndrome is a congenital disorder that causes an impairment of myeloid differentiation in the bone marrow characterized by severe neutropenia, which can be treated with recombinant human granulocyte colony-stimulating factor (G-CSF). We present the case of a 13-year-old boy with Kostmann's syndrome who was treated with recombinant human G-CSF from age 3.5 years. His growth and development was normal, although complicated by intermittent infections. Bone mineral density (BMD) measurement revealed severe osteopenia at the spine and hips (lumbar spine BMD 0.486 g/cm(2); Z score -3.6), and he was referred to the Endocrine Service. Relevant laboratory evaluation showed a pretreatment ionized calcium level at the upper limit of normal (1.28 mmol/L; range: 1.13-1.32 mmol/L), suppressed intact parathyroid hormone (iPTH) level (12 pg/mL; range: 10-65 pg/mL), and a low 1,25-dihydroxy vitamin D level (21 pg/mL; range: 24-65 pg/mL). He had evidence of increased bone turnover evidenced by elevated urinary deoxypyridinoline (DPD) cross-links (46.9 nmol/mmol creatinine; range: 2-34 nmol/mmol creatinine) and a simultaneous increase in markers of bone formation with elevated osteocalcin level (200 ng/mL; normal: 20-80 ng/mL) and alkaline phosphatase level (236 IU/mL; normal: 38-126 IU/mL). Because of clinical concern for his skeletal health, bisphosphonate therapy with intravenous pamidronate was initiated. One month after treatment, the iPTH and DPD cross-links were in the normal range (54 pg/mL and 17.7 nmol/mmol creatinine, respectively) and the 1,25-dihydroxy vitamin D level was elevated (111 pg/mL). Four months after treatment, there was a striking increase in BMD at the lumbar spine (+30.86%), femoral necks (left, +20.02%; right, +17.98%), and total hips (left, +18.40%; right, +15.94%). Seven months after bisphosphonate therapy, his biochemical parameters showed a return toward pretreatment levels with increasing urinary DPD cross-links (28.7 nmol/mmol creatinine) and decreasing iPTH (26 pg/mL). However, the BMD continued to increase (8 months posttreatment), but the magnitude of the increment was attenuated (lumbar-spine, +4.8%; left total hip, +1.2% and right total hip +2.4%), relative to BMD at 4 months. Eight months after the initial treatment, his iPTH was suppressed at 14 pg/mL and he again received pamidronate (at a lower dose); 3 months later, he had an additional increase in BMD (lumbar spine +7.4%, left total hip +3.9%, right total hip +2.7%), relative to the previous study. We hypothesize that prolonged administration of G-CSF as treatment for Kostmann's syndrome is associated with increased bone resorption, mediated by osteoclast activation and leading to bone loss. In children, the resulting osteopenia can be successfully managed with antisreorptive bisphosphonate therapy with significant improvement in bone density. Measurements of biochemical parameters of bone turnover can be used to monitor the magnitude and duration of the therapeutic response and the need for BMD reassessment and, perhaps, retreatment.