[FLT3-ITD mutation-positive acute myeloid leukemia undergoing clonal transition with PTPN11 mutation at relapse]

A 28-year-old man was diagnosed with acute myelomonocytic leukemia. He achieved complete remission (CR) after two cycles of induction therapy. However, after consolidation therapy, bone marrow aspiration performed to prepare for allogeneic hematopoietic stem cell transplantation revealed disease relapse. Companion diagnostics confirmed the presence of the FLT3-ITD mutation. The patient received gilteritinib monotherapy and achieved CR. Subsequently, he underwent unrelated allogeneic bone marrow transplantation. One year after transplantation, the patient relapsed, and gilteritinib was resumed. However, the leukemia progressed, and panel sequencing using a next-generation sequencer showed that the FLT3-ITD mutation disappeared. A mutation in PTPN11, which regulates the RAS/MAPK signaling pathway, was also detected. Gilteritinib was discontinued, and the patient achieved CR with salvage chemotherapy. He underwent related haploidentical peripheral blood stem cell transplantation but died of relapse. This was a case in which genetic analysis revealed clonal transition and acquisition of resistance to treatment.

Elevation of Urinary Liver-Type Fatty Acid-Binding Protein Is a Harbinger of Poor Patient Prognosis after Allogeneic Stem Cell Transplantation

Several recent studies have demonstrated that urinary levels of liver-type fatty acid-binding protein (L-FABP) can be used to stratify the prognosis of cardiac disease, cardiac intensive care unit admission, cirrhosis, and coronavirus disease 2019. Our initial prospective study revealed that urinary L-FABP (uL-FABP) was associated with a high probability of acute kidney injury after stem cell transplantation (SCT); however, the relevance of elevated uL-FABP to the prognosis of patients undergoing SCT remains to be determined. We aimed to investigate whether uL-FABP levels can be used to stratify patient prognosis after SCT. To achieve this aim, we conducted a new long-term follow-up study using data from patients enrolled in our preceding prospective cohort study. Patients were classified into high and low uL-FABP groups based on levels measured at baseline (ie, before initiating the conditioning regimen), using an uL-FABP cutoff of 8.4 μg/gCr, which was determined based on data from healthy adults. uL-FABP levels were also measured on days 0, 7, and 14 after SCT. Cox proportional hazard regression was used to examine the effects of each factor on survival outcomes, and Fine-Gray regression was used in the presence of competing risks. Multivariate analysis incorporating confounders was then performed for factors with P < .1 in univariate analysis. In total, 20 of 84 patients (23.8%), 57 of 84 patients (67.9%), 34 of 49 patients (69.4%), and 34 of 46 patients (73.9%) were classified into the high uL-FABP group at baseline and on days 0, 7, and 14, respectively. The 5-year overall survival (OS) rate was 23.9% in the high uL-FABP group and 68.9% in the low uL-FABP group. The multivariate analysis identified a high uL-FABP level at baseline as a significant prognostic factor for poor OS (hazard ratio [HR], 3.54; P = .002). The 5-year cumulative incidence rate for nonrelapse mortality (NRM) was 50.0% in the high uL-FABP group and 19.9% in the low uL-FABP group. In the multivariate analysis, high uL-FABP at baseline was a significant prognostic factor for NRM (HR, 3.37; P = .01). uL-FABP levels did not significantly stratify the cumulative incidence of relapse (HR, 2.13; P = .11). uL-FABP levels on days 0, 7, and 14 were not significant predictors of survival. High uL-FABP level before initiation of conditioning significantly influences OS and NRM following SCT, whereas a high uL-FABP level at any point after the conditioning regimen does not. Our results show that measuring uL-FABP level at baseline may be a simple way to predict survival in patients undergoing SCT.

Clinical entity of cytomegalovirus disease in patients with malignant lymphoma on bendamustine therapy: a single-institution experience

We investigated the incidence, risk factors, and clinical outcomes of cytomegalovirus (CMV) disease in patients with B-cell lymphoma treated with a bendamustine-containing regimen. The incidence of CMV disease was analyzed after starting treatment with 139 regimens in 126 patients. Clinically significant CMV disease was observed in seven patients. The median duration between bendamustine initiation and the diagnosis of CMV disease was 69 d (range, 40-233), and the median of cycles completed at onset was 2 (range, 1-6). Furthermore, the incidence of CMV disease was significantly higher in the elderly patients than that in the younger patients. The target organs of CMV disease were the liver, gastrointestinal tract, lungs, and retinas. Antiviral therapy was administered to all patients. However, the recurrence of CMV disease was observed in two patients. This study provides information that could contribute to clinicians' decision-making on lymphoma therapy using bendamustine.

Pulmonary Veno-Occlusive Disease after Autologous Stem Cell Transplantation

Pulmonary veno-occlusive disease (PVOD) is an extremely rare condition in oncology practice. Although PVOD is clinically similar to pulmonary arterial hypertension, the conditions differ in terms of pathophysiology, management, and prognosis. This report discusses the case of a 47-year-old woman who developed dyspnea and fatigue after high-dose cyclophosphamide chemotherapy and autologous hematopoietic stem cell transplantation for relapsed lymphoma. The patient exhibited tachycardia, tachypnea, and hypotension, but other findings in the physical examination were unremarkable. The imaging studies showed no evidence of pulmonary embolism, but multiple ground-glass opacities and bilateral pleural effusions were observed on chest high-resolution computed tomography scans. In the right heart catheterization study, the mean pulmonary artery pressure and pulmonary vascular resistance were 35 mm Hg and 5.93 Wood units, respectively, with a normal pulmonary capillary wedge pressure of 10 mm Hg. Pulmonary function tests revealed a remarkable reduction in the percentage predicted value of diffusing capacity of the lungs for carbon monoxide to 31%. Lymphoma progression, collagen diseases, infectious diseases such as human immunodeficiency virus or parasitic infections, portal hypertension, and congenital heart disease were carefully excluded as these are also capable of causing pulmonary arterial hypertension. Thereafter, we reached a final diagnosis of PVOD. The patient was treated with supplemental oxygen and a diuretic during 1 month of hospitalization, which relieved her right heart overload symptoms. Herein, we present the patient's clinical course and diagnostic workup because misdiagnosis or inappropriate treatment can lead to unfavorable outcomes in patients with PVOD.

[Thrombotic microangiopathy with gastrointestinal hemorrhage during carfilzomib therapy for multiple myeloma]

A 70-year-old woman was admitted to the hospital with loss of appetite and melena. She was diagnosed with multiple myeloma 7 years ago and had been on carfilzomib, lenalidomide, and dexamethasone (KRd) therapy for a month because her disease had a relapsed/refractory. On admission, her laboratory tests revealed hemolytic anemia with schizocytes, thrombocytopenia, and acute renal dysfunction. TMA (thrombotic microangiography) caused by carfilzomib was suspected. The possibility of thrombotic thrombocytopenia was considered, and steroid pulse therapy was initiated. Her condition improved significantly after she stopped taking carfilzomib, plasma exchange, hemodiafiltration, steroid pulse therapy, and abstaining from food. The previously reported cases of carfilzomib-induced TMA included fever, gastrointestinal symptoms (nausea/vomiting, diarrhea), and acute renal disorders (lower extremity edema, decreasing urine output). As far as we know, this is the first case of carfilzomib-induced TMA with bleeding as the first symptom.

Relationship between Carnitine Deficiency and Tyrosine Kinase Inhibitor Use in Patients with Chronic Myeloid Leukemia

BACKGROUND

Some chemotherapeutic agents cause carnitine deficiency, which causes general fatigue. However, there is no study on carnitine deficiency in patients with chronic myeloid leukemia (CML) during tyrosine kinase inhibitor (TKI) therapy.

OBJECTIVE

In this study, we investigated carnitine concentrations in patients with CML receiving TKI therapy.

METHOD

This study included patients with well-controlled CML. Total carnitine and free carnitine concentrations were evaluated using the enzyme cycling method. The brief fatigue inventory (BFI) and cancer fatigue scale (CFS) were used to assess general fatigue developed during TKI therapy.

RESULTS

Fifty-five patients on TKI therapy were included. Of these, 12 (21.8%) patients had low free carnitine concentrations. Free carnitine concentrations were higher in men than in women. Younger age was closely associated with lower free carnitine concentrations. TKI type, TKI dose, treatment response, or therapy duration were not associated with free carnitine concentrations. None of the scores (the global fatigue score with the BFI and CFS score) correlated with carnitine concentrations. Concentrations of free carnitine in patients in the treatment-free remission group were slightly higher than those in the TKI group, with only 9.1% having a low concentration of free carnitine.

CONCLUSION

Carnitine deficiency is probably not a major cause of general fatigue but may occur in patients with CML receiving TKI therapy.

Absolute Lymphocyte Counts After Lenalidomide Initiation may Predict the Prognosis of Patients With Relapsed or Refractory Multiple Myeloma

BACKGROUND/AIM

We assessed the prognosis of patients with refractory or relapsed multiple myeloma (RRMM) by focusing on the change in absolute lymphocyte counts (ALCs) after lenalidomide and dexamethasone (Ld) initiation.

PATIENTS AND METHODS

In total, 72 patients with RRMM were treated with Ld. ALCs were evaluated before treatment and at 1, 2, and 3 months after Ld initiation. The median ALCs in the entire cohort before and at 1, 2, 3 months after Ld initiation were 1,131, 1,059, 1,222, and 1,162/μl, respectively.

RESULTS

ALCs before Ld initiation did not affect time to next treatment (TNT) or overall survival (OS). However, the patients with ALCs equal to or greater than the median at 3 months showed relatively better TNT than those with lower lymphocyte counts, with a significant difference. OS was also significantly longer in patients with higher ALCs.

CONCLUSION

Immunomodulation by lenalidomide may improve prognosis in patients with RRMM.

Maintenance Therapy With Bortezomib and Dexamethasone for Transplant-ineligible Patients With Multiple Myeloma

BACKGROUND/AIM

Here, we investigated whether bortezomib as a maintenance therapy affected outcomes in transplant-ineligible patients with multiple myeloma (MM).

PATIENTS AND METHODS

Following induction therapy with bortezomib, maintenance therapy with bortezomib (1.3 mg/m ² ) and dexamethasone (20 mg) was administered once or twice every 4 weeks until disease progression. The endpoints of this study were time to next treatment and overall survival.

RESULTS

Seventy-six newly diagnosed, transplant-ineligible patients were treated with a bortezomib-based regimen; 28 discontinued induction therapy, 27 did not receive maintenance therapy after induction therapy (the non-maintenance group), and 21 did (the maintenance group). In the three groups, the median times to the next required treatment were 3, 14, and 37 months, respectively. The 3-year overall survival rates were 55%, 69%, and 85%, respectively. There were no significant differences in patient characteristics between the non-maintenance and maintenance groups, except for poorer estimated glomerular filtration rates in the maintenance group.

CONCLUSION

Bortezomib maintenance therapy may be a useful option for transplant-ineligible patients with MM.

A bolus of saline injection leads to increase in coronary flow based on the viscosity reduction effect: the mechanism of saline induced Pd/Pa ratio

Background

In conjunction with fractional flow reserve (FFR), our previous study has shown the accuracy and utility of saline induced Pd/Pa ratio (SPR) for the assessment of myocardial ischemia. However, the potential mechanism how saline injection leads to increase in coronary flow remains speculative.

Purpose

This study aimed to clarify the underlying mechanism of SPR by using swine models.

Methods

The study was conducted in four swine models, and bolus of 25°C saline, 40°C saline, and 25°C dextran was injected at rates of 40mL/5sec through a catheter inserted into the superior mesenteric artery. Its peripheral arterioles were observed and recorded by a digital microscope, and transit time of each fluid and a luminal diameter of arterioles before and after injection were measured.

Results

The result from arterioles diameters of pre- and post-injection (0.049±0.016mm vs. 0.050±0.016mm; P=0.636) indicated that luminal diameters remained unchanged regardless of fluid administration. The transit time of 25°C saline was significantly shorter than 25°C dextran (3.19±0.68sec vs. 6.15±1.19sec; P&lt;0.0001). Although the result showed no significance, the transit time of 40°C saline with lower viscosity was shorten compared to 25°C saline (3.1±0.43sec vs. 3.65±0.46sec; P=0.088).

Conclusions

Compared to 25°C dextran (viscosity of 4.991mPa·s) having the same viscosity as 37°C whole blood, 25°C saline (viscosity of 1.012mPa·s) caused increasing to double the intravascular flow volume without dilating arterioles. The results strongly suggested that the potential mechanism of SPR was viscosity reduction effect. Combined with FFR which is based on vasodilation-mediated hyperemia, these findings may contribute to clarifying the pathophysiology and especially the microcirculation in coronary artery diseases.

Funding Acknowledgement

Type of funding source: None

The developing mechanism of atherosclerotic lesion in coronary side branch on the ventricular free wall differs by the location of lesion

Background

The effective treating method of coronary side branch lesions such as ostial stenosis or thin arteries has not been established. On the other hand, tortuous side branch rarely has stenotic lesions.

Purpose

We focused on coronary side branches on the ventricular free wall, and examined coronary risk factors and bending and stretching motion of branch which can contribute to the development of atherosclerotic lesion.

Methods

In elective and first-time coronary angiograms, we included side branches on the ventricular free wall (&gt;2mm in diameter) and excluded previously treated ones. Study A; we divided arteries into proximal, middle, and distal segment, and examined the presence of tortuosity and stenotic lesions exceeding 50% diameter stenosis (DS) for each segment. A score of 1 was assigned to tortuous segment, and 0 to non-tortuous one. Study B; we included stenotic lesion (&gt;50% DS) in side branch ostium and excluded those extended across main coronary arteries. Relation between lesions and patients' characteristics was examined.

Results

Study A; in 1,828 side branches from 472 patients, middle and distal segments had significantly higher tortuosity score than proximal (0.68, 0.78 vs. 0.34; p&lt;0.0001). On the contrary, proximal segments had more stenotic lesions except ostial stenosis (230 vs. 69, 5; p&lt;0.0001). Study B; in 1,740 side branches from 465 patients, 122 ostial stenotic lesions were found (7.0%). Multivariate logistic regression analysis revealed diabetes mellitus and age as independent contributors to development of ostial stenosis (Table).

Conclusions

Side branch stenosis developed less frequently in middle and distal segments, where stronger ventricular wall motion reinforces bending and stretching motion and tortuosity of arteries. This fact indicates that those characteristics may prevent developing atherosclerosis through increasing shear stress. On the other hand, diabetes mellitus strongly contributes to the development of ostial stenosis. Thus, the developing mechanism of atherosclerotic lesion in side branch on the ventricular free wall differs by the location of lesion.

Funding Acknowledgement

Type of funding source: None

Effectiveness of Preceding Solo Kidney Transplantation for Type 1 Diabetes With End-Stage Renal Failure

Preceding solo kidney transplantation for type 1 diabetes with end-stage renal failure is controversial because of less pancreatic graft survival in pancreas transplantation after kidney transplantation (PAK) than in simultaneous pancreas and kidney transplantation (SPK).

METHODS

To study the effectiveness of preceding solo kidney transplantation for type 1 diabetes with end-stage renal failure, comparative retrospective analysis was performed between SPK (n = 232) and PAK (n = 39) that were performed until December 2016.

RESULTS

At 1, 3, and 5 years, pancreatic graft survival in SPK was 87.5%, 86.4%, and 82.8%, respectively, and 87.1%, 65.0%, and 49.1%, respectively, in PAK, which showed lesser long-term graft survival than SPK. Because 10 cases out of 16 (62.5%) failed into pancreatic graft loss with rejection in PAK, which was about 3 times more than in SPK, control of rejection is very important; rejection episodes were decreased by rabbit antithymocyte globulin induction resulting in improved graft survival. Five-year patient survival was 88.0% in SPK and 96.6% in PAK.

CONCLUSION

Considering patient survival, preceding solo kidney transplantation for type 1 diabetes with end-stage renal failure should be performed if a donor is available.

[Achievement of a stringent complete response with low-dose pomalidomide monotherapy in a multiple myeloma patient]

An 80-year-old man presented to our hospital with a thoracic vertebrae compression fracture. He was diagnosed with IgG-λ myeloma (International Staging System stage II, Durie-Salmon stage IIIA). Since melphalan-prednisolone (MP) was not effective, we treated him with lenalidomide and low-dose dexamethasone (DEX) (Ld), achieving a partial response. As DEX provoked edema and psychiatric symptoms, the patient disagreed with its use, and pomalidomide (POM) monotherapy was initiated. Although the POM dosage was reduced to 1-2 mg/day due to somnolence, which was reported as an adverse event, stringent complete response (sCR) was achieved and sustained for 10 months following 11 cycles of low-dose POM monotherapy. It is assumed that sCR was achieved with low-dose POM monotherapy due to its early introduction as well as there being no high-risk chromosomal abnormalities. Even though adverse events develop with a standard dose, a continuation of low-dose POM is considered more important than discontinuation.

Laparoscopy-Assisted Spleen-Preserving Distal Pancreatectomy for Living-Donor Pancreas Transplantation

BACKGROUND

Living pancreas transplantation plays an important role in the treatment of patients with severe type 1 diabetes. However, pancreatectomy is very invasive for the donor, and less-invasive surgical procedures are needed. Although some reports have described hand-assisted laparoscopic surgery for distal pancreatectomy in living-donor operations, less-invasive laparoscopy-assisted (LA) procedures are expected to increase the donor pool. We herein report the outcomes of four cases of LA spleen-preserving distal pancreatectomy (Warshaw technique [WT]) in living pancreas donors.

PATIENTS AND METHODS

Four living pancreas donors underwent LA-WT at our institution from September 2010 to January 2013. All donors fulfilled the donor criteria established by the Japan Society for Pancreas and Islet Transplantation.

RESULTS

The median donor age was 54 years. Two donors underwent left nephrectomy in addition to LA-WT for simultaneous pancreas-kidney transplantation. The median donor operation time for pancreatectomy was 340.5 minutes. The median pancreas warm ischemic time was 3 minutes. The median donor blood loss was 246 g. All recipients immediately achieved insulin independence. One donor required reoperation because of obstructive ileus resulting from a port-site hernia. Another donor developed a pancreatic fistula (International Study Group of Pancreatic Fistula grade B), which was controlled with conservative management. After a maximum follow-up of 73 months, no clinically relevant adverse events had occurred. These results were comparable with those of previous studies concerning living-donor pancreas transplantation.

CONCLUSION

The LA-WT is a safe and acceptable operation for living-donor pancreas transplantation.

Outcome of renal transplantation in patients with type 2 diabetic nephropathy: a single-center experience

BACKGROUND

Renal transplantation has been established as a treatment for end-stage renal disease (ESRD) due to diabetic nephropathy. However, few studies have focused on the outcome after renal transplantation in patients with ESRD and type 2 diabetic nephropathy. To investigate the effect of renal transplantation on ESRD with type 2 diabetic nephropathy, we retrospectively analyzed patients who received renal transplantation at our facility. This study aimed to compare the outcome of renal transplantation for type 2 diabetic nephropathy with that for nondiabetic nephropathy.

METHODS

We studied 290 adult patients, including 65 with type 2 diabetic nephropathy (DM group) and 225 with nondiabetic nephropathy (NDM group), who underwent living-donor renal transplantation at our facility from February 2008 to March 2013. We compared the 2 groups retrospectively.

RESULTS

In the DM and NDM groups, the 5-year patient survival rates were 96.6% and 98.7%, and the 5-year graft survival rates were 96.8% and 98.0%, respectively, with no significant differences between the groups. There were no significant differences in the rates of surgical complications, rejection, and infection. The cumulative incidence of postoperative cardiovascular events was higher in the DM group than in the NDM group (8.5% vs 0.49% at 5 years; P = .002).

CONCLUSIONS

Patient and graft survival rates after renal transplantation for type 2 diabetic nephropathy are not inferior to those for recipients without diabetic nephropathy. Considering the poor prognosis of patients with diabetic nephropathy on dialysis, renal transplantation can provide significant benefits for these patients.

Impact of flow cytometry crossmatch B-cell positivity on living renal transplantation

BACKGROUND

Various studies have reported poorer graft survival among individuals displaying T-cell-positive flow cytometry crossmatches (FCXM). Good outcomes have been observed in immunologically high-risk patients with the use of rituximab, plasmapheresis, and γ-globulin. Because the relevance of FCXM B-cell-positivity (BCXM (+)) alone remains controversial, we examined its impact on living donor renal transplantations.

PATIENTS AND METHODS

We retrospectively studied 146 adult renal transplantation recipients from April 2007 to June 2012, dividing the patients into BCXM (+) (n = 31) versus BCXM (-) recipients (n = 115). We examined patient and graft survivals as well as rejection rates at 0 to 3, 3 to 12, and 12 to 24 months. We also determined the incidence of infectious diseases. We performed stepwise multivariate regression to identify risk factors contributing rejection episodes.

RESULTS

One-year patient and graft survivals were 100% in both groups. The BCXM (-) group have a 16.8% rejection probability whereas the BCXM (+) group, 33.2% (P = .201). There were no significantly differences in the incidence of infectious diseases. Only the rate of a sensitizing history was an independent risk factor for a rejection episode.

CONCLUSION

BCXM (+) showed only a tendency but not a significant impact on rejection episodes compared with BCXM (-); short-term graft survivals were similar.

Decontamination of outdoor school swimming pools in Fukushima after the nuclear accident in March 2011

Because of radioactive fallout resulting from the Fukushima Daiichi Nuclear Power Plant (NPP) accident, water discharge from many outdoor swimming pools in Fukushima was suspended out of concern that radiocesium in the pool water would flow into farmlands. The Japan Atomic Energy Agency has reviewed the existing flocculation method for decontaminating pool water and established a practical decontamination method by demonstrating the process at eight pools in Fukushima. In this method, zeolite powder and a flocculant are used for capturing radiocesium present in pool water. The supernatant is discharged if the radiocesium concentration is less than the targeted level. The radioactive residue is collected and stored in a temporary storage space. Radioactivity concentration in water is measured with a NaI(Tl) or Ge detector installed near the pool. The demonstration results showed that the pool water in which the radiocesium concentration was more than a few hundred Bq L was readily purified by the method, and the radiocesium concentration was reduced to less than 100 Bq L. The ambient dose rates around the temporary storage space were slightly elevated; however, the total increase was up to 30% of the background dose rates when the residue was shielded with sandbags.

Laparoscopic splenectomy using pneumoperitoneum or gasless abdominal wall lifting: a 15-year single institution experience

INTRODUCTION

Laparoscopic splenectomy using pneumoperitoneum has been performed since 1992. The gasless abdominal wall-lifting method for laparoscopic splenectomy was introduced as an alternative. This retrospective study was undertaken to compare results using the two techniques.

METHODS

Between 1995 and 2010, 54 patients underwent laparoscopic splenectomy at a single institution; 30 underwent the procedure using the gasless technique and 24 using pneumoperitoneum. There were no significant differences between the two groups regarding age, sex or BMI, but more patients underwent concurrent operations in the pneumoperitoneum group. The abdominal wall-lift system with subcutaneous K-wires was used for the gasless method.

RESULTS

Intraoperative blood loss was similar in the two groups (193.0 ± 196.7 mL gasless, 217.3 ± 296.6 mL pneumoperitoneum; P > 0.05), but operative time (182.1 ± 92.1 min, 135.1 ± 46.1 min; P < 0.05), and resected spleen weight (306.1 ± 297.7 g, 138 ± 81.0 g; P < 0.05) were significantly different. In the gasless group, additional procedures included conversion (n = 1), mini-laparotomy (n = 2), and CO(2) insufflation (n = 2). Excluding the concurrent living-related kidney donor patients, hospital stay was similar (6.9 ± 2.5 days, 6.3 ± 2.0 days, P > 0.05).

CONCLUSION

Although gasless laparoscopic splenectomy is feasible, there are disadvantages, particularly the restricted operative working space in some patients. These results suggest that either technique may be used on an individual basis in patients undergoing laparoscopic splenectomy.

Effects of O2 Gas Addition on Diamond-Like Carbon Film Deposition

The role of 02 gas addition on the deposition of Diamond-like Carbon (DLC) film was studied for hard disk drive (HDD) media application. The influence of 02 gas mixing ratio on DLC film quality was investigated using the dc magnetron sputtering method with a solid graphite target and Ar, CH4 and 02 mixing gases. The 02 mixing ratio was varied between 0% and 50%. Film quality was evaluated using Raman spectroscopy and XPS. When 02 gas mixing ratio increased the peak in Raman spectra shifted gradually to higher wavenumbers and its bandwidth became narrower. This indicates graphite component increased in the DLC film. In addition, the lubricant coverage on oxygen-containing DLC was improved. Because adding oxygen increases the terminations of carbonyl group on DLC surface, this result suggests that the polar surface causes higher affinity for the lubricant

High resolution neutron protein crystallography. Hydrogen and hydration in proteins

Neutron diffraction provides an experimental method of directly locating hydrogen atoms in proteins, and the development of the neutron imaging plate (NIP) became a breakthrough event in neutron protein crystallography. The general features of the NIP are reviewed. A high resolution neutron diffractometer dedicated to biological macromolecules (BIX-3) with the NIP has been constructed at Japan Atomic Energy Research Institute and this has enabled 1.5 Å resolution structural analyses of several proteins to be carried out. The specifications of BIX-3 and LADI (a quasi-Laue type diffractometer installed in the Institut Laue-Langevin) are compared. The crystal structures of myoglobin, wild type rubredoxin and a mutant of rubredoxin have been carried out using BIX-3. From these studies, several topics, such as the location of hydrogen bonds and certain acidic hydrogen atoms, the identification of methyl hydrogen atoms, details of H/D exchange and dynamical behavior of hydration structures have been investigated, and important information has been extracted from the structural results. Finally, a systematic procedure to grow large single crystals of proteins or nucleic acids is described.