CD8-positive T-cell lymphoproliferative disorder of the uterus: a new subtype of indolent extranodal T-cell neoplasm?

A 51-year-old female with menorrhagia was found to have a cervical polyp. Polypectomy and endometrial curettage showed an atypical lymphoid infiltrate. Hysterectomy was performed, showing extensive myometrial infiltration by small, cytologically bland CD3-positive αß T cells with a non-activated cytotoxic phenotype and a low proliferative rate. PCR showed clonal TCR-ß gene rearrangement. Lymph nodes were uninvolved. PET-CT was negative. A diagnosis of CD8-positive T-cell lymphoproliferative disorder (T-LPD) was made. At 6 months, the patient was asymptomatic with a negative repeat PET-CT. A critical recent advance in the classification of lymphoid neoplasms is the recognition of indolent extranodal T-LPDs, including those of the gastrointestinal tract (T-cell and NK-cell types) and skin (small/medium CD4-positive and acral CD8-positive). However, T-LPDs of the uterus are rare. Two indolent T-LPDs of the uterus have been reported, both showing a CD8-positive, nonactivated cytotoxic phenotype, low proliferative rate, and clonal TCR rearrangement. Neither developed systemic disease nor recurrence. The etiology of indolent T-LPDs and their relationship to overt T-cell lymphomas remain poorly understood. T-LPDs of the uterus may arise from effector memory T-cells that establish long-term, tissueresident immunologic memory following exposure to fetal extravillous trophoblastic cell alloantigens during a previous pregnancy. Neither our patient nor the 2 previously reported had a current pregnancy or a known recent infection or toxic exposure, and the event(s) triggering evolution into T-LPD are unknown. Indolent T-LPDs can be encountered at new and unusual extranodal sites; knowledge of their clinicopathological features will help avoid unnecessary cytotoxic chemotherapy and improve understanding of this group of disorders.

Relation between the epicardial fat thickness and the cardiac conduction system in children and adolescents with diabetes.

INTRODUCTION: Atherosclerosis in patients with type 1 diabetes starts early in childhood with subclinical abnormalities. The epicardial fat thickness (EFT) is a novel method for detecting these early changes. Furthermore, electrocardiographic markers may be altered in patients with diabetes owing to early cardiovascular changes. This study aimed to determine the relationship between EFT and electrocardiographic markers in children with type 1 diabetes mellitus. METHODS: Children with type 1 diabetes who were followed up at Alexandria University Children's Hospital Diabetes Clinic were enrolled in this study. The study recruited three groups of participants, including 20 patients with a diabetes duration of less than 5 years, 20 patients with a diabetes duration of 5 years or more, and 20 healthy controls. All participants were evaluated with emphasis on anthropometric measurements, fasting blood glucose levels, and lipid profile. HbA1c levels were measured in the cohort with diabetes. All participants underwent electrocardiography for measurement of P-wave dispersion, corrected QT interval and its dispersion, and Tp-e measurement. Echocardiography was performed to measure the EFT. RESULTS: Among all participants, EFT was significantly higher in children with a diabetes duration of ≥ 5 years (p= 0.009). Furthermore, P-wave dispersion was significantly prolonged in children with diabetes compared to that in non-diabetics (p= 0.041). There was a statistically significant correlation between EFT and P-wave dispersion in patients with diabetes aged  5 years (p = 0.021). CONCLUSIONS: Measurement of EFT by Echocardiography is a novel and easy way to predict early cardiovascular changes in children with diabetes, including conduction system disorders.

Antitumoral properties of the pomegranate peel and blueberry extracts against tongue carcinoma (in vitro study).

Background: Oral squamous cell carcinoma (OSCC) is one of the most common cancers globally. Considering the drawbacks of the traditional treatment phytochemicals have been introduced to the research field with consideration of their minimal, or no side effects and good efficacy against cancer cells. Pomegranate peel and blueberries are very well-known phytochemicals in this context. Material and methods: Methanolic extracts are prepared from both pomegranate peel (PPE) and blueberry (BE) dried powders. The antioxidant content was determined by ORAC assay for both extracts. The cytotoxic levels of the extracts and IC50 on the HNO-97 cell line were defined using the colorimetric SRB assay. Then flow cytometric apoptosis analysis of the IC50 of both extracts was performed. Finally, an investigation of the metastasis through the wound healing assay was performed for both extracts. Results: A significant difference in the antioxidant content was found between PPE and BE ethanolic extracts. The Ic50 for the PPE-treated cell line was 73.35 µg/ml while the BE showed it at 525.38 µg/ml with a significant difference between them. Both PPE and BE showed significant induction of cancer cell apoptosis with much better results with PPE treatment. The wound healing assay showed significant inhibition of cell migration when treated with PPE while there was not any significant effect on cell migration when treated with BE. Conclusion: With the consideration that, the Phytochemicals used are well-known fruits with no harm on normal tissues. Low doses of PPE exert incredibly significant alteration in the HNO-97 tongue cancer cell proliferation, inducing apoptosis and inhibition of cancer cell migration. Meanwhile, treatment with BE needs much higher doses for showing anti-proliferative properties of cancer cells and induce cancer cell apoptosis. This gives promising results for further investigations about using them as a treatment or adjunctive treatment for oral cancer cases.

Updates in the Classification of T-cell Lymphomas and Lymphoproliferative Disorders.

PURPOSE OF REVIEW: Mature T/NK-cell neoplasms comprise a heterogeneous group of diseases with diverse clinical, histopathologic, immunophenotypic, and molecular features. A clinically relevant, comprehensive, and reproducible classification system for T/NK-cell neoplasms is essential for optimal management, risk stratification, and advancing understanding of these diseases. Two classification systems for lymphoid neoplasms were recently introduced: the 5th edition of World Health Organization classification (WHO-HAEM5) and the 2022 International Consensus Classification (ICC). In this review, we summarize the basic framework and updates in the classification of mature T/NK-cell neoplasms. RECENT FINDINGS: WHO-HAEM5 and ICC share basic concepts in classification of T/NK-cell neoplasms, emphasizing integration of clinical presentation, pathology, immunophenotype, and genetics. Major updates in both classifications include unifying nodal T-follicular helper-cell lymphomas into a single entity and establishing EBV-positive nodal T/NK-cell lymphoma as a distinct entity. However, some differences exist in taxonomy, terminology, and disease definitions. The recent classifications of mature T/NK-cell neoplasms are largely similar and provide new insights into taxonomy based on integrated clinicopathologic features.

Prevalence and Associated Factors of Vitamin D Deficiency in High Altitude Region in Saudi Arabia: Three-Year Retrospective Study.

Background: Vitamin D has many functions in the human body, and its deficiency is associated with skeletal and non-skeletal diseases. Vitamin D deficiency (blood level of 25 (OH) vitamin D < 20 ng/mL) has been reported worldwide, including Kingdom of Saudi Arabia (KSA). Its prevalence and associated factors vary according to KSA region. Therefore, this study aimed to explore the prevalence and risk factors of vitamin D deficiency in the Taif region of KSA. Methods: This retrospective study included patients who attended outpatient clinics at the Alameen General Hospital from 2019 to 2021. Demographic, clinical, and laboratory data were collected using a hospital software system. Results: The study included 2153 patients and vitamin D deficiency was diagnosed in 900 (41.8%) of whom were diagnosed with vitamin D deficiency. It was more common in males (P=0.021), younger age (<0.001), and in patients without comorbidities. There was a positive correlation between 25 (OH) vitamin D levels and blood cholesterol, high-density lipoprotein, calcium, and vitamin B12 levels. In the binary logistic regression analysis, age was the most significant predictor (P<0.001), followed by the absence of thyroid disease (P=0.012) and asthma (P=0.030). Conclusion: Vitamin D deficiency is common in the Saudi population despite sunny weather in KSA. It is more prevalent among males, younger individuals, and those without comorbidities such as thyroid diseases and asthma.

Incidence and Determinants of Complications of Percutaneous Kidney Biopsy in a Large Cohort of Native Kidney and Kidney Transplant Recipients.

Objectives: This study aimed to determine the incidence and factors associated with complications for kidney biopsy. Percutaneous kidney biopsy is a useful diagnostic procedure. Haemorrhagic complications may occur following the procedure. Methods: The present study retrospectively analysed the records of patients who had percutaneous renal biopsy between March 2013 and March 2018. The cohort included both native kidney and native transplant biopsies. We have included only the first biopsy for each patient; repeat biopsies were excluded from the analysis. Results: A total of 1,198 patients (332 transplant recipients and 886 native kidney patients) were included in this study. Major complications occurred in 1.5% (n = 18) of patients (1.4% in native kidney biopsies versus 1.6% in kidney transplant recipients). Adequate renal tissue (core of >6 glomeruli) was obtained in 91% of the patients. Data analysis revealed that the incidence of major complications in the native kidney biopsy increase with an age >65 years (odds ratio = 2.4; 95% Confidence interval [CI] = 1.5-5.6), estimated glomerular filtration rate (eGFR) <30 mL/min/m2 (odds ratio = 9.7; 95% CI = 3.4-18.2) and anaemia (odds ratio = 3.2; 95% CI = 1.7-5.2). In transplant recipients kidney biopsy, the incidence of complications was increased with age >65 years (odds ratio = 2.8; 95% CI = 1.7-7.3), eGFR <30 mL/min/m2 (odds ratio = 11.3; 95% CI = 3.5-16.8) and anaemia (odds ratio = 2.4; 95% CI = 1.4-4.7). Conclusion: The incidence of major complications following kidney biopsy was 1.5% for a cohort of native kidney biopsy and kidney transplant biopsies. Age >65 years, lower eGFR <30 mL/min/m2 and anaemia were independent risk predictors for the occurrence of major complications in both native and transplant kidney biopsies.

Dynamics of Mycobacterium tuberculosis Lineages in Oman, 2009 to 2018.

Study aim. Effective Tuberculosis (TB) control measures in Oman have reduced the annual incidence of tuberculosis cases by 92% between 1981 and 2016. However, the current incidence remains above the program control target of <1 TB case per 100,000 population. This has been partly attributed to a high influx of migrants from countries with high TB burdens. The present study aimed to elucidate Mycobacterium tuberculosis infection dynamics among nationals and foreigners over a period of 10 years. Methods. The study examined TB cases reported between 2009 and 2018 and examined the spatial heterogeneity of TB cases and the distribution of M. tuberculosis genotypes defined by spoligotypes and MIRU-VNTR among Omanis and foreigners. Results. A total of 484 spoligoprofiles were detected among the examined isolates (n = 1295). These include 943 (72.8%) clustered and 352 (27.2%) unique isolates. Diverse M. tuberculosis lineages exist in all provinces in Oman, with most lineages shared between Omanis and foreigners. The most frequent spoligotypes were found to belong to EAI (318, 30.9%), CAS (310, 30.1%), T (154, 14.9%), and Beijing (88, 8.5%) lineages. However, the frequencies of these lineages differed between Omanis and foreigners. Of the clustered strains, 192 MTB isolates were further analysed via MIRU-VNTR. Each isolate exhibited a unique MIRU-VNTR profile, indicative of absence of ongoing transmission. Conclusions. TB incidence exhibits spatial heterogeneity across Oman, with high levels of diversity of M. tuberculosis lineages among Omanis and foreigners and sub-lineages shared between the two groups. However, MIRU-VNTR analysis ruled out ongoing transmission.

Evaluation of urinary FOXP3 mRNA as a biomarker of lupus nephritis in Egyptian patients with systemic lupus erythematosus.

AIM: Lupus nephritis (LN) is one of the most serious complications of SLE. Tregs (Regulatory T lymphocytes) are thought to play a part in the pathogenesis of SLE. According to recent research, Foxp3, a Treg identification marker, plays a significant role in the pathogenesis of SLE. This study aimed to compare the urinary Foxp3 mRNA levels of patients with active and inactive forms of LN and healthy control subjects to see whether it played a role in disease activity. METHODS: We measured FOXP3 messenger RNA (mRNA) expression in the urine of 50 people with active LN, 50 people with inactive lupus, and 50 healthy people. RESULTS: We found that the expression level of FOXP3 was significantly higher in urine from patients with active LN than from subjects with inactive lupus and healthy controls (22.93 ± 4.13 vs 5.66 ± 0.47 vs 0.57 ± 0.15copy; P < 0.001).Urinary FOXP3 mRNA level significantly correlated with SLEDAI (0.000057) In the active group, urinary FOXP3 mRNA level also significantly correlated with histological activity index (< 0.00001). CONCLUSION: We concluded that urinary FOXP3 mRNA is elevated in patients with active LN and that it is linked to the SLEDAI and the severity of the disease. FOXP3 mRNA in urine sediment may be used as a non-invasive biomarker for evaluating the severity of LN and risk stratification.

Clinical and Laboratory Findings of COVID-19 in High-Altitude Inhabitants of Saudi Arabia.

Background: SARS-CoV-2, the causative agent of COVID-19, continues to cause a worldwide pandemic, with more than 147 million being affected globally as of this writing. People's responses to COVID-19 range from asymptomatic to severe, and the disease is sometimes fatal. Its severity is affected by different factors and comorbidities of the infected patients. Living at a high altitude could be another factor that affects the severity of the disease in infected patients. Methods: In the present study, we have analyzed the clinical, laboratory, and radiological findings of COVID-19-infected patients in Taif, a high-altitude region of Saudi Arabia. In addition, we compared matched diseased subjects to those living at sea level. We hypothesized that people living in high-altitude locations are prone to develop a more severe form of COVID-19 than those living at sea level. Results: Age and a high Charlson comorbidity score were associated with increased numbers of intensive care unit (ICU) admissions and mortality among COVID-19 patients. These ICU admissions and fatalities were found mainly in patients with comorbidities. Rates of leukocytosis, neutrophilia, higher D-dimer, ferritin, and highly sensitive C-reactive protein (CRP) were significantly higher in ICU patients. CRP was the most independent of the laboratory biomarkers found to be potential predictors of death. COVID-19 patients who live at higher altitude developed a less severe form of the disease and had a lower mortality rate, in comparison to matched subjects living at sea level. Conclusion: CRP and Charlson comorbidity scores can be considered predictive of disease severity. People living at higher altitudes developed less severe forms of COVID-19 disease than those living at sea level, due to a not-yet-known mechanism.

Changes of Urinary Cytokines in Non-Diabetic Obese Patients After Laparoscopic Sleeve Gastrectomy.

INTRODUCTION: Adipose tissues synthesize and secrete various proinflammatory and anti-inflammatory mediators, termed cytokines. This work aims to assess different serum and urinary cytokine levels before and 12 months after laparoscopic sleeve gastrectomy (LSG). PATIENTS: This prospective study was performed on 61 obese non-diabetic patients who underwent LSG. All patients were followed up postoperatively at 12 months with the assessment of arterial blood pressure, microalbuminuria, urinary and serum levels of inflammatory cytokines (macrophage migration inhibitory factor "MIF," monocyte chemotactic protein "MCP"-1, chemokine (C-C motif) ligand 15 (CCL-15), and CCL-18), in addition to serum creatinine, total cholesterol, and C-reactive protein (CRP). RESULTS: Mean BMI showed decreased substantially from 44.78 ± 3.59 Kg/m2 to 34.56 ± 2.45. Systolic blood pressure decreased from 147.03 ± 16.89 mmHg to 128.82 ± 12.52 and diastolic blood pressure decreased from 90.51 ± 12.71 mmHg to 79.69 ± 10.39. At one-year of follow-up, there was statistically significant decrease of mean serum creatinine, total cholesterol, CRP, CCL-15, CCL-18, MIF/creatinine ratio, MCP-1/creatinine ratio, CCL-15/creatinine ratio, and CCL-18/creatinine ratio (P value <0.001). CONCLUSION: Improvement of systemic and renal inflammatory states after LSG may positively affect obesity-related renal disease by steering the adipokine levels towards anti-inflammatory profiles.

Impact of laparoscopic sleeve gastrectomy on fibrosis stage in patients with child-A NASH-related cirrhosis.

PURPOSE: Bariatric surgery can improve non-alcoholic fatty liver disease (NAFLD). Yet data on the effect on fibrosis are insufficient and controversial. This work endeavored to evaluate the safety of laparoscopic sleeve gastrectomy (LSG) in cases that have compensated non-alcoholic steatohepatitis (NASH)-related cirrhosis and its impact on fibrosis stage. METHODS: The current prospective work involved 132 cases with Child-A NASH-related cirrhosis suffering from morbid obesity scheduled for LSG. They were subjected to preoperative assessment, wedge biopsy, and ultrasound-guided true-cut liver biopsy after 30 months. Patients were included if proved to have F4 fibrosis initially. The liver condition was assessed based on the NALFD Activity Score (NAS). The primary outcome measure was the impact of LSG on fibrosis stage and its relation to weight loss. RESULTS: The analysis included only 71 patients who completed the 30-month follow-up period. By the end of the follow-up interval, there was a substantial weight loss with a reasonable resolution of comorbidities. The median NAS decreased significantly from 6 (1-8) to 3 (0-6) after surgery. Fibrosis score regressed to F2 in 19 patients (26.8%) and F3 in 29 (40.8%). Patients with improved scores had a significantly higher amount of weight loss (p < 0.001). Improvement was more frequent in males (p = 0.007). By 30 months after treatment, 53.8% of cases with borderline NASH and 36.8% of those with probable NASH showed complete resolution, and 44.7% of patients with NASH showed improvement. Steatosis improved in 74.6% of patients (p < 0.001). CONCLUSION: In patients with NASH-related liver cirrhosis of Child class A, LSG may be a secure approach for the management of morbid obesity. It has a long-term benefit for both obesity and liver condition with significant improvement of steatosis, steatohepatitis, and fibrosis.

Effect of weight loss induced by laparoscopic sleeve gastrectomy on liver histology and serum adipokine levels.

BACKGROUND & AIM: Bariatric surgery is a valid treatment option for persons with non-alcoholic fatty liver disease. This study prospectively examined the impact of laparoscopic sleeve gastrectomy (LSG) on liver histopathology, and blood levels of adiponectin, leptin, resistin, and pre-B cell enhancing factor/Nampt/visfatin. PATIENTS & METHODS: In 81 patients with non-alcoholic fatty liver disease who underwent LSG, paired liver biopsies and blood specimens were obtained before and 18 months after LSG. Differences between preoperative and 18 months postoperative data were tested by paired Student's t-test or Wilcoxon rank test as appropriate. RESULTS: At follow up, there was a significant improvement in biochemical markers for glucose homeostasis, including fasting glucose, HbA1c, insulin levels, and homeostatic model assessment index. Postoperative liver function tests, namely serum alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transpeptidase level, showed a significant improvement compared to before weight loss. The number of patients who had definite, borderline, or no non-alcoholic steatohepatitis was 43 (53%), 27 (33%), and 11 (14%), respectively, at baseline, and 9 (11%), 32 (40%), and 40 (49%) at 18-month post-surgery follow up. A significant reduction in steatosis, liver fibrosis, lobular inflammation, and hepatocyte ballooning was observed in the postoperative biopsies (P < 0.001 each). In addition, at the follow-up assessment, there was a significant increase in serum adiponectin levels and significant decline in serum levels of leptin, resisitin, and pre-B cell enhancing factor/Nampt/visfatin. CONCLUSION: Weight loss after sleeve gastrectomy was associated with a significant improvement in several metabolic parameters, liver enzyme levels, liver histopathology, and changes in serum adipokine levels towards antidiabetic and anti-inflammatory profiles.

Acceleration of Gastric Emptying and Improvement of GERD Outcome After Laparoscopic Sleeve Gastrectomy in Non-diabetic Obese Patients.

PURPOSE: Obesity has become a pandemic nowadays. Bariatric surgery is increasingly performed to manage obesity. Currently, laparoscopic sleeve gastrectomy (LSG) is a widely accepted procedure given its feasibility and efficacy. Previous studies revealed conflicting results regarding the change of gastric emptying following sleeve gastrectomy. The primary aim of the present study is to assess gastric motor function by gastric emptying scintigraphy in a cohort of non-diabetic patients undergoing laparoscopic sleeve gastrectomy (LSG) for treatment of severe obesity. METHODS: This prospective observational study included 100 obese, non-diabetic patients attending the surgery clinic at Cairo University Hospitals and Al Azhar University Hospitals. LSG was performed following a standardized protocol, with no complications observed. All patients had gastric emptying scintigraphy done through a standard semisolid meal (250 kcal), marked with 0.5 mCiTc 99, pre-operatively and 3 months after LSG. RESULTS: The mean age was 38.71 years (9.2) and males comprised 57% of the cohort. The body mass index, low-density lipoproteins, and glycated hemoglobin declined significantly at 3-month postsurgery. The scintigraphy study revealed a significantly reduced percent retention at equivalent time points 3 months after LSG. In addition, the percent of patients suffering from GERD decreased significantly after LSG. CONCLUSION: Gastric emptying becomes faster after LSG in morbidly obese non-diabetic patients. GERD symptoms improve after surgery.

Urinary podocalyxin: Is it a real index of disease activity in egyptian patients lupus nephritis?

Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease characterized by production of a number of antinuclear antibodies. Podocyte injury is an important feature and can be detected by several markers including podocalyxin. We aimed to evaluate the impact of SLE on urinary levels of podocalyxin and to determine its relationship to renal biopsy, proteinuria, and disease activity in lupus nephritis (LN) patients. Sixty individuals were recruited; 30 SLE patients with LN as well as 30 healthy volunteers and they were subjected to full history, clinical examination, kidney function, protein/creatinine ratio, urinary podocalyxin, and kidney biopsy. Patients with LN had higher level of urinary podocalyxin (3.96 ± 2.24) than the other group (0 ± 0), (P <0.001). Class IV LN was the most common class found among LN patients [18 cases (60%)]. There was a statistically significant positive correlation between SLE disease activity index score, protein/creatinine ratio, and urinary podocalyxin (P <0.001, r = 0.98) (P <0.001, r = 0.765). There was a statistically significant negative correlation between serum albumin, serum calcium, and urinary podocalyxin (P = 0.001, r = -0.589) (P = 0.025, r = -0.407). Urinary podocalyxin level significantly predicts the pathological impact of SLE on the kidney and could be used as a noninvasive marker for such effect and its progression.

Study of changes of obesity-related inflammatory cytokines after laparoscopic sleeve gastrectomy.

BACKGROUND: Chronic inflammation in adipose tissue may play a substantial role in the pathogenesis of obesity-related metabolic disorders. The present study aims to evaluate the changes in adipocytokines, bile acids, fibroblast growth factor 19 (FGF-19) and pro-inflammatory cytokines 6 months after laparoscopic sleeve gastrectomy (LSG). METHODS: This prospective study included 75 obese patients with body mass index >35 kg/m2 who underwent LSG. All patients were recruited preoperatively and followed up post-operatively at 6 months, with laboratory assessment of their cytokines including adiponectin, leptin, resistin, bile acid, interleukin (IL)-6, IL-8, tumour necrosis factor-α, monocyte chemotactic protein-1, high-sensitivity C-reactive protein, plasminogen activator inhibitor-1, serum amyloid-A and FGF-19. RESULTS: There were statistically highly significant changes regarding anthropometric parameters (weight, body mass index and waist-to-hip ratio), blood glucose and lipid profile as well as liver enzymes at 6 months post-sleeve gastrectomy. The present study showed that the levels of serum adiponectin and FGF-19 significantly increased at 6 months of follow-up after surgery (P < 0.001), while the levels of serum leptin, resistin, high-sensitivity C-reactive protein, plasminogen activator inhibitor-1 and serum amyloid-A significantly decreased at 6 months of follow-up after surgery (P < 0.001). There were no significant differences regarding serum bile acid, IL-6, IL-8, tumour necrosis factor-α and monocyte chemotactic protein-1. CONCLUSION: Weight loss after LSG is associated with significant improvement of the adipokine levels towards anti-diabetic and anti-inflammatory profiles. Future studies should use a larger sample size and longer follow-up periods.

Isolation of diverse members of the Aquificales from geothermal springs in Tengchong, China.

The order Aquificales (phylum Aquificae) consists of thermophilic and hyperthermophilic bacteria that are prominent in many geothermal systems, including those in Tengchong, Yunnan Province, China. However, Aquificales have not previously been isolated from Tengchong. We isolated five strains of Aquificales from diverse springs (temperature 45.2-83.3°C and pH 2.6-9.1) in the Rehai Geothermal Field from sites in which Aquificales were abundant. Phylogenetic analysis showed that four of the strains belong to the genera Hydrogenobacter, Hydrogenobaculum, and Sulfurihydrogenibium, including strains distant enough to likely justify new species of Hydrogenobacter and Hydrogenobaculum. The additional strain may represent a new genus in the Hydrogenothermaceae. All strains were capable of aerobic respiration under microaerophilic conditions; however, they had variable capacity for chemolithotrophic oxidation of hydrogen and sulfur compounds and nitrate reduction.