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Biomedical subjects

J W Young

Publications and source records attributed to J W Young.

At least 19 recordsLinked to original sources

Exogenous glucagon effects on health and reproductive performance of lactating dairy cows with mild fatty liver.

Severe fatty liver, a metabolic disease of dairy cows in early lactation, results in decreased health and reproductive performance, but can be alleviated by treatment with i.v. injections of glucagon. Mild fatty liver in cows effects on health and reproductive performance were determined by treatment with 14-day s.c. injections of glucagon at 7.5 or 15 mg/day. Multiparous Holstein cows (n=32) were grouped into Normal and Susceptible based on liver triacylglycerol concentrations (>1% liver tissue biopsy wet weight) at day 8 postpartum (day 0=day of parturition). Susceptible cows (n=24) were assigned randomly to three groups and s.c. injected with 0mg glucagon [60 ml 0.15M NaCl] [n=8] (same for Normal cows), 2.5 mg glucagon, or 5 mg glucagon every 8 h for 14 days, beginning day 8 postpartum. Mild fatty liver resulted in an increased number of days with elevated body temperature during the injection period, an increased incidence of mastitis after glucagon treatment, increased days to first estrus and insemination, increased days before conception occurred, and decreased conception rate. In cows with mild fatty liver, glucagon (15 mg/day) decreased the number of days with elevated body temperature and the incidence of mastitis after hormone treatment. From these results, we suggest that mild fatty liver is detrimental to health and reproduction of dairy cows and, furthermore, that exogenous glucagon decreases some of these detrimental effects.

Animals↗

In vitro expansion of Ag-specific T cells by HLA-A*0201-transfected K562 cells for immune monitoring.

BACKGROUND: Development of a practical and sensitive assay for evaluating immune responses against cancer Ag has been a challenge for immune monitoring of patients. We have established a reproducible method using peptide-pulsed K562-A*0201 cells as APC to expand Ag-specific T cells in vitro. This method may be applied for monitoring T-cell responses in cancer immunotherapy clinical trials. METHODS: Autologous PBMC from HLA-A*0201+ healthy donors and patients with melanoma were stimulated with peptide-pulsed K562-A*0201 cells under varying conditions. We investigated (1) different culture conditions, including the requirements for serum and cytokines for expansion of CD8+ T lymphocytes; (2) a range of peptide concentrations for Ag loading; (3) phenotypic characterization of responding T cells; and (4) APC:responder ratios and their effects on T-cell expansion. We validated these conditions by ELISPOT and intracellular cytokine staining (ICS) assays using peptides from influenza, Epslein-Barr Virus (EBV) and tyrosinase. RESULTS: Conditions for optimal T-cell expansion using K562-A*0201 APC included input of 2 x 10(6) PBMC, a 10 microg/mL peptide concentration to pulse K562-A*0201 cells, a 1:30 APC:responder T-cell ratio and culture in 10% autologous plasma supplemented with IL-2 and IL-15. In these conditions, Ag-specific T cells expanded >100-fold over a 10-day culture period (peak at day 12). DISCUSSION: This bulk culture method is simple and reliable for expanding human Ag-specific T cells using peptide-pulsed K562-A*0201 cells. This HLA-matched APC line can be adapted to other HLA haplotypes, and has advantages for monitoring clinical trials of immunotherapy with limited availability of autologous APC and PBMC from patients.

Antigen-Presenting Cells↗

Prevention of fatty liver in transition dairy cows by subcutaneous injections of glucagon.

The main objective of this study was to test the extent to which injecting glucagon subcutaneously for 14 d beginning at d 2 postpartum would prevent fatty liver development in transition dairy cows. Twenty-four multiparous Holstein cows were fed 6 kg of cracked corn in addition to their standard diet during the last 30 d of a dry period to induce postpartum development of fatty liver. Glucagon at either 7.5 or 15 mg/d or saline (control) was injected subcutaneously 3 times daily for 14 d beginning at d 2 postpartum. Glucagon at 15 mg/ d prevented liver triacylglycerol accumulation in postpartum dairy cows. Glucagon at 7.5 mg/d showed potential for fatty liver prevention. Glucagon increased concentration of plasma glucose and insulin and decreased plasma nonesterified fatty acid concentrations. No effects of glucagon were detected on plasma beta-hydroxybutyrate concentrations. Glucagon affected neither feed intake nor milk production. Moreover, milk composition was not altered by glucagon. Milk urea N concentrations decreased, and plasma urea N concentrations tended to decrease during glucagon administration, indicating that glucagon may improve protein use. Liver glycogen concentrations were not affected by glucagon. No significant differences in body condition scores were detected among treatments throughout the study. These results indicate that subcutaneous glucagon injections can prevent fatty liver in transition dairy cows without causing major production and metabolite disturbances.

Acetoacetates↗

An investigation into the relationship between the severity of obstructive sleep apnoea/hypopnoea syndrome and the vertical position of the hyoid bone.

OBJECTIVE: This study aimed to identify a correlation of diagnostic clinical significance between the vertical position of the hyoid bone in relation to structures within the dentofacial skeleton and: (1) The severity of obstructive sleep apnoea hypopnoea syndrome, (OSAHS), (2) Decisions relating to the management of the condition. DESIGN AND SETTING: Randomised retrospective survey of cephalometric records of subjects having been diagnosed as suffering with OSAHS by in patient overnight polysomnographic testing at the Edinburgh Royal Infirmary Sleep Centre, 2001-2002. MATERIALS AND METHODS: Pre-polysomnograph orthoposition lateral cephalograms of 94 subjects tested, during the period from April 1996 to September 1997, were randomly selected and traced following strict adherence to standard protocol. Edentulous arches (one or both) formed the only exclusion criterion owing to obvious effects upon vertical dimensions of the cervico-pharyngeal region. Measurement of the vertical position of the hyoid bone was made relative to a number of planes validated by numerous previous cephalometric investigations, and these were recorded along with the apnoea/hypopnoea index (AHI), and subsequent management (mandibular repositioning appliances (MRA) / continuous positive airway pressure (CPAP)). Correlations between measurements and AHI were investigated using Spearman's Correlation Coefficients, and analysis of the relationship between hyoid bone position and management groups was undertaken using Wilcoxon Ranked Sum Testing. DISCUSSION AND RESULTS: Statistically significant correlations were found between all linear measurements locating the hyoid bone in the vertical plane and subject AHI. The linear relationships were less reliable for subjects with AHI > 100, possibly due to a breakdown in the body's ability to respond posturally in order to maintain airway patency in more extreme cases. When the treatment groups (MRA/CPAP) were considered independently there was found to be a clear delineation between the two groups at a length of 120 mm between the sella (S- a point upon the anterior cranial base) and the hyoid (H). This, in turn, may suggest that cephalometric radiographs may be used as a reproduciable diagnostic tool.

Cephalometry↗

Invited review: pathology, etiology, prevention, and treatment of fatty liver in dairy cows.

Fatty liver (i.e., hepatic lipidosis) is a major metabolic disorder of many dairy cows in early lactation and is associated with decreased health status and reproductive performance. In severe cases, milk production and feed intake are decreased. Therefore, a practical preventative or an efficacious treatment of fatty liver could save millions of dollars yearly in treatment, replacement, and production losses for dairy farmers. Fatty liver develops when the hepatic uptake of lipids exceeds the oxidation and secretion of lipids by the liver, which usually is preceded by high concentrations of plasma NEFA mobilized from adipose tissue. Excess lipids are stored as triacylglycerol in the liver and are associated with decreased metabolic functions of the liver. Liver can be categorized into normal liver or mild, moderate, or severe fatty liver; the latter can be subdivided further into nonencephalopathic severe fatty liver and hepatic encephalopathy. Insufficient or unbalanced dietary intake, obesity, and elevated estrogen concentrations are involved in the etiology of fatty liver, which is associated with greater incidence of dystocia, diseases, infections, and inflammations. Because even mild fatty liver is associated with decreased health status and reproductive performance of dairy cows, prevention of fatty liver by supplying cows with sufficient nutrients and a clean and health-promoting environment in the peripartal period would reduce production losses of cows more than would any treatment of fatty liver. This, however, might not be enough for cows that are obese or do not eat well, had calving difficulties or twins, have metabolic or infectious diseases, or are in severe negative energy balance because of high milk production immediately after calving. Potential and commonly used preventatives, as well as treatments, are discussed in the review. Currently, detection of fatty liver is possible only by minor surgery. Ultrasonic techniques offer a potential tool to noninvasively detect fatty liver. Future gene-array and proteomic studies may provide means to detect early molecular events in the etiology of fatty liver plus their connection with immune function and reproductive performance so that more effective treatments and preventatives of fatty liver can be developed. Such advances hopefully will make fatty liver a problem of the past.

Animal Nutritional Physiological Phenomena↗

Metabolic responses of lactating dairy cows to single and multiple subcutaneous injections of glucagon.

Continuous, intravenous infusions of glucagon improve carbohydrate status in lactating dairy cows without increasing concentrations of plasma NEFA. The objective was to test whether single subcutaneous injections and multiple subcutaneous injections of glucagon delivered at 8-h intervals over 14 d improve the carbohydrate status in lactating dairy cows without increasing concentrations of plasma BHBA and NEFA. In a single-injection experiment, four midlactation cows each were injected with 2.5 and 5 mg of glucagon 1 wk apart. In a multiple-injection experiment, nine cows, assigned randomly to three treatments, were injected subcutaneously with 0, 2.5, or 5 mg of glucagon every 8 h for 14 d, beginning at d 8 postpartum. Single subcutaneous injections of glucagon increased concentrations of plasma glucagon and single and multiple subcutaneous injections of glucagon increased concentrations of plasma glucose, with larger increases at the 5-mg dosage. Injections of 5 mg of glucagon increased concentrations of plasma insulin in both experiments, whereas the 2.5-mg dosage increased plasma insulin only in the multiple-injection experiment. The response of glucose and insulin to injections of 5 mg of glucagon persisted throughout the 14-d injection period. Concentrations of plasma NEFA decreased in the single-injection experiment, and concentrations of BHBA decreased after 5 mg of glucagon was injected in the multiple-injection experiment. These results document that both single and multiple injections of 5 mg of glucagon over 14 d consistently improve the carbohydrate status of dairy cows and decrease concentrations of plasma NEFA and BHBA.

3-Hydroxybutyric Acid↗

Effects of exogenous glucagon on lipids in lipoproteins and liver of lactating dairy cows.

Decreased concentrations of phospholipids, free cholesterol, and cholesteryl ester in plasma and liver are associated with fatty liver, a major metabolic disease of dairy cows in early lactation. The objective was to test whether daily subcutaneous injections of 7.5 and 15 mg of glucagon, which can decrease concentrations of liver triacylglycerol, affect concentrations of plasma lipoprotein components and liver lipids other than triacylglycerol. Multiparous Holstein cows (n = 32) were grouped on the basis of liver triacylglycerol concentrations at d 8 postpartum into "normal" (n = 8; triacylglycerol <1% liver wet wt) and "susceptible to fatty liver" (n = 24; triacylglycerol >1% liver wet wt) cows. Susceptible cows were assigned randomly to three groups and beginning at d 8 postpartum received 0 (same for Normal cows), 2.5, or 5 mg of glucagon by subcutaneous injections every 8 h for 14 d. In comparison to saline injections, subcutaneous injections of glucagon either increased or tended to increase concentrations of phospholipids and free cholesterol in liver, with greater increases of the latter during ambient temperatures below 35 degrees C. Glucagon injections decreased or tended to decrease concentrations of very low-density lipoprotein-triacylglycerol, high-density lipoprotein1-phospholipids, and high-density lipoprotein2-free cholesterol in plasma, with no changes of the latter two during ambient temperatures below 35 degrees C. The results indicate that subcutaneously administered glucagon has only minor effects on the lipid transport in plasma of dairy cows in early lactation with more beneficial effects occurring during ambient temperatures below 35 degrees C and, most importantly, no indications that glucagon has negative effects.

Animals↗

Potential treatment of fatty liver with 14-day subcutaneous injections of glucagon.

Fatty liver is a major metabolic disease of dairy cows in early lactation that can be treated with 14-d continuous, intravenous infusions of 10 mg/d of glucagon. The objective was to test whether similar effects can be obtained with 14-d subcutaneous 7.5- or 15-mg daily dosages of glucagon beginning at d 8 postpartum. Multiparous Holstein cows (n = 32) were grouped on the basis of their liver triacylglycerol concentration at d 8 postpartum into "normal" (n = 8; triacylglycerol < 1% liver wet wt) and "susceptible" (n = 24; triacylglycerol > 1% liver wet wt) cows. Susceptible cows were assigned randomly to three groups and beginning at d 8 postpartum received 0, 2.5, or 5 mg of glucagon in 60 ml of saline by subcutaneous injections every 8 h for 14 d. Beginning at d 8 postpartum, normal cows received 60 ml of saline by subcutaneous injections every 8 h for 14 d. Both dosages of glucagon increased concentrations of plasma glucose and insulin and decreased concentrations of plasma nonesterfied fatty acids. Glucagon injections of 15 mg/d decreased concentrations of liver triacylglycerol in cows older than 3.5 yr, but not in younger multiparous cows. Our results document that subcutaneous injections of glucagon have the potential to decrease the degree of fatty liver in older dairy cows in early lactation.

Animals↗

Breakthrough Scedosporium apiospermum (Pseudallescheria boydii) brain abscess during therapy for invasive pulmonary aspergillosis following high-risk allogeneic hematopoietic stem cell transplantation. Scedosporiasis and recent advances in antifungal therapy.

Systemic scedosporiasis due to the anamorph or asexual form Scedosporium apiospermum (Pseudallescheria boydii) has become an important cause of opportunistic mycosis, especially in patients undergoing high-risk hematopoietic stem cell transplantation. We report a case of rapidly progressive cerebellar hyalohyphomycosis due to Scedosporium apiospermum in an allogeneic marrow graft recipient receiving treatment for severe graft-versus-host disease. This fatal breakthrough intracranial abscess, due to amphotericin B-resistant (minimum inhibitory concentration > 16 micro g/ml) mold, developed during the course of systemic antifungal therapy given for multicentric pulmonary aspergillosis. Despite treatment with high-dose Abelcet (10 mg/kg daily), free amphotericin B was not detected in postmortem cerebellar tissue. A broad-spectrum triazole-based agent (voriconazole/UK-109, 496--Vfend), and a novel fungal cell wall inhibitor, an echinocandin/pneumocandin analog (caspofungin/MK-0991--Cancidas), which exhibit excellent in vitro activity against most clinical Pseudallescheria boydii-Scedosporium apiospermum isolates, have recently become available in the United States and may provide much needed treatment options for patients at risk.

Adult↗

Identification of poor prognostic features among patients requiring mechanical ventilation after hematopoietic stem cell transplantation.

Patients who develop respiratory failure requiring mechanical ventilation after hematopoietic stem cell transplantation (HSCT) have very high mortality. Several investigators have identified prognostic features that can be used to identify a subset of these patients who are virtually certain to die, yet these have never been prospectively assessed. The objectives of this study were to determine the accuracy of published prognostic features for mortality and to determine the survival of patients who recover from respiratory failure. A systematic review of the literature was undertaken to identify reported poor prognostic features and survival rates. The study validated the reported poor prognostic features on a prospective, multicenter inception cohort of 226 patients with respiratory failure requiring mechanical ventilation after HSCT. The main outcome measures were determination of a baseline probability of death, drawn from literature review; likelihood ratio of mortality for each prognostic feature determined from the validation cohort; conditional probability of death in the presence of each feature; and 6-month survival of those who recover. Patients requiring mechanical ventilation after HSCT have a baseline probability of death of 82% to 96%. In the setting of combined hepatic and renal dysfunction, the probability of death rises to 98% to 100%. Other previously reported prognostic features are less strongly associated with mortality. For patients who recover from respiratory failure, the proportion surviving 6 months or longer ranges from 27% to 88%. It was concluded that in patients requiring mechanical ventilation after HSCT, the presence of combined hepatic and renal dysfunction is highly predictive of death. The presence of this feature may justify the recommendation to withdraw life-sustaining measures.

Adult↗

Retrovirally transduced mouse dendritic cells require CD4+ T cell help to elicit antitumor immunity: implications for the clinical use of dendritic cells.

Presentation of MHC class I-restricted peptides by dendritic cells (DCs) can elicit vigorous antigen-specific CTL responses in vivo. It is well established, however, that T cell help can augment CTL function, raising the question of how best to present tumor-associated MHC class I epitopes to induce effective tumor immunity. To this end, we have examined the role of MHC class II peptide-complexes present on the immunizing DCs in a murine melanoma model. To present MHC class I- and II-restricted Ags reliably on the same cell, we retrovirally transduced bone marrow-derived DCs with the model Ag OVA encoding well-defined class I- and II-restricted epitopes. The importance of CD4+ T cells activated by the immunizing DCs in this model is demonstrated by the following findings: 1) transduced DCs presenting class I and class II epitopes are more efficient than class I peptide-pulsed DCs; 2) MHC class II-deficient DCs fail to induce tumor protection; 3) CD4+ T cell depletion abolishes induction of tumor protection; and 4) DCs presenting bovine serum Ags are more effective in establishing tumor immunity than DCs cultured in syngeneic serum. When MHC class II-deficient DCs were directly activated via their CD40 receptor, we indeed observed a moderate elevation of OVA-specific CTL activity. However, this increase in CTL activity was not sufficient to induce in vivo tumor rejection. Thus, our results demonstrate the potency of genetically modified DCs that express both MHC class I and II epitopes, but caution against the use of DCs presenting only the former.

Animals↗

Circulating human B cells that express surrogate light chains and edited receptors.

Immunoglobulin gene recombination can result in the assembly of self-reactive antibodies. Deletion, anergy or receptor editing normally silence B cells that produce these autoantibodies. Receptor editing is highly efficient in mouse B cells that carry pre-recombined autoantibody transgenes or gene "knock-ins". However, it has been difficult to identify cells that have edited receptors in unmanipulated mice and humans. To try to identify such cells we isolated and characterized B cells that coexpress surrogate and conventional light chains (V-preB+L+) from the blood of normal human donors. V-preB+L+ B cells express RAG mRNA, display an unusual heavy and light chain antibody repertoire consistent with antiself reactivity, and show evidence of receptor editing. These cells accumulate in the joints of patients with rheumatoid arthritis, consistent with a role for V-preB+L+ B cells and receptor editing in autoimmune disease.

Agammaglobulinemia↗

Virtual endoscopy--comparison with colonoscopy in the detection of space-occupying lesions of the colon.

BACKGROUND AND STUDY AIMS: A new technique has been described which combines abdominal helical computed tomography (CT) scanning and virtual reality computer technology, known as virtual colonoscopy (VC); the reconstructed images provide a simulation of the interior of the colon as viewed by endoscopy. We compared VC with conventional colonoscopy in patients with suspected or known colonic neoplasia. PATIENTS AND METHODS: A total of 38 patients, in whom there was a high likelihood of colonic polyps or cancer, underwent a noncontrast helical CT scan of the abdomen and pelvis after regular colonoscopy bowel preparation. The images were reconstructed into a VC presentation and compared with the subsequent conventional colonoscopy in a blinded manner. RESULTS: Conventional colonoscopy identified a total of 24 polyps 5 mm or greater. VC correctly identified five of 13 polyps 5-9 mm in size, and ten of 11 lesions greater than or equal to 10 mm in diameter. The reasons for four missed lesions were identified as being secondary to a collapsed rectum in two patients and stool in the right colon in two patients. The sensitivity and specificity per patient of VC for lesions greater than or equal to 5 mm were 66.7% and 75.0% respectively, and for lesions greater than 1 cm were 90.0% and 82.1%, respectively. CONCLUSIONS: Virtual colonoscopy is feasible, well tolerated, and capable of detecting most lesions greater than 10 mm in diameter. This technique is continuing to be developed and warrants further evaluation as a diagnostic and screening tool in colorectal neoplasia.

Adult↗

Enzyme, bacterial inoculant, and formic acid effects on silage composition of orchardgrass and alfalfa.

We evaluated the effects of cellulase (from Trichoderma longibrachiatum) application rates on neutral detergent fiber (NDF) concentration and fermentation products of orchardgrass (Dactylis glomerata L.) and alfalfa (Medicago sativa L.) silages harvested with decreasing dry matter (DM) digestibility. Additionally, the impacts of inoculant (Lactobacillus plantarum and Pediococcus cerevisiae), pectinase (from Aspergillus niger), or formic acid on silage composition were studied. Forages wilted to a DM content of about 320 g/kg were ensiled in laboratory silos for 60 d. Cellulase, combined with inoculant, was applied at 2, 10, and 20 ml/kg of herbage (at least 2500 IU/ml). Cellulase at 10 ml/kg was also applied alone or in combination with pectinase and inoculant or formic acid. The NDF concentration of orchardgrass silage decreased with increasing cellulase up to 20 ml/kg, at which NDF content was decreased by 30%. The NDF concentration of alfalfa silage decreased with increasing cellulase application up to 10 ml/kg, at which NDF content was decreased by 13%. Immature plants were more responsive to cellulase treatment than mature plants. Cellulase at 2 ml/kg combined with inoculant improved fermentation characteristics of the silages but generally, there was no effect on silage fermentation by higher cellulase applications, resulting in an accumulation of sugar. The improved fermentation of orchardgrass treated with cellulase and inoculant was mostly related to the effect of inoculant, whereas cellulase alone improved fermentation characteristics of alfalfa silage and this effect was enhanced by addition of inoculant. Decreased NDF and increased sugar concentrations did not improve the in vitro DM digestibility of cellulase-treated silages.

Aspergillus niger↗

Paucity of functional T-cell memory to melanoma antigens in healthy donors and melanoma patients.

The functional characteristics of CD8+ T cells specific for melanoma antigens (MAs) have often been defined after in vitro culture using nonprofessional antigen-presenting cells. We have examined CD8+ T-cell immunity to MAs and a viral antigen (influenza) in uncultured T cells of healthy donors and melanoma patients using autologous, mature, monocyte-derived dendritic cells (DCs) pulsed with peptide antigens and viral vectors. Antigen-specific IFN-gamma-producing T cells reactive with HLA-A*0201-restricted peptides from four melanoma antigens (MelanA/MART-1, MAGE-3, tyrosinase, and gp100) were detected only at low frequencies (<30 per 2 x 10(5) peripheral blood mononuclear cells for each of the MAs) from HLA-A2.1-positive healthy donors (n = 12) and patients with stages III/IV melanoma (n = 8). Detection of MA-specific, but not influenza matrix peptide (Flu-MP)-specific, T cells required a high concentration (10 microg/ml) of the peptide in this assay. Furthermore, these T cells did not recognize endogenously processed antigen on tumor cell lines or cells infected with viral vectors capable of expressing MAs. The use of autologous, mature DCs led to a significant increase in the number of Flu-MP, but not MA-specific, T cells in 16-h ELISPOT assays for both melanoma patients and healthy donors. In 1-week cocultures with DCs pulsed with 10 microg/ml peptide, MelanA/MART-1-specific T cells did not readily proliferate or differentiate into lytic effectors, in contrast to strong influenza-specific lytic responses. Therefore, despite distinct memory responses to influenza antigens, melanoma patients and healthy controls have a paucity of MA-reactive memory T cells, failing to rapidly generate IFN-gamma-secreting lytic effectors in short-term assays, even when stimulated by DCs.

Antigens↗

Comparison of immune reconstitution after unrelated and related T-cell-depleted bone marrow transplantation: effect of patient age and donor leukocyte infusions.

Unrelated bone marrow transplantation (BMT) is often complicated by fatal opportunistic infections. To evaluate features unique to immune reconstitution after unrelated BMT, the lymphoid phenotype, in vitro function, and life-threatening opportunistic infections after unrelated and related T-cell-depleted (TCD) BMT were analyzed longitudinally and compared. The effects of posttransplant donor leukocyte infusions to treat or prevent cytomegalovirus (CMV) or Epstein-Barr virus (EBV) infections on immune reconstitution were also analyzed. This study demonstrates that adult recipients of TCD unrelated BMTs experience prolonged and profound deficiencies of CD3(+), CD4(+), and CD8(+) T-cell populations when compared with pediatric recipients of unrelated BMT and adults after related BMT (P <.01), that these adults have a significantly increased risk of life-threatening opportunistic infections, and that the rate of recovery of CD4 T cells correlates with the risk of developing these infections. Recovery of normal numbers of CD3(+), CD8(+), and CD4(+) T-cell populations is similar in children after related or unrelated BMT. This study also demonstrates that adoptive immunotherapy with small numbers of unirradiated donor leukocytes can be associated with rapid restoration of CD3(+), CD4(+), and CD8(+) T-cell numbers, antigen-specific T-cell responses, and resolution of CMV- and EBV-associated disease after unrelated TCD BMT.

Adolescent↗