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Biomedical subjects

S M Chen

Publications and source records attributed to S M Chen.

At least 55 records · Page 3Linked to original sources

Association of Sauropus androgynus and bronchiolitis obliterans syndrome: a hospital-based case-control study.

In late April 1995, an outbreak of a poorly defined respiratory illness related to the ingestion of leaves of Sauropus androgynus was observed in southern Taiwan. To further evaluate the association between S. androgynus and bronchiolitis obliterans syndrome, a hospital-based case-control study was conducted with one case group and three different control groups at Veterans General Hospital-Kaohsiung between April and September 1995. A total of 54 cases (50 females, 4 males), 54 age- and sex-matched neighborhood controls, 54 matched routine physical check-up controls, and 54 matched self-referred patron controls (who had ingested S. androgynus yet without obstructive physiology) were interviewed for clinical symptoms, history of S. androgynus consumption, and potential confounding factors. All 54 cases (100%) ingested S. androgynus compared with only five (9%) neighborhood controls (matched odds ratio (OR) incalculable, p < 0.001) and two (4%) physical check-up controls (matched OR incalculable, p < 0.001). In the univariate analysis of 54 cases and 54 self-referred patron controls, factors associated with an increased risk of bronchiolitis obliterans syndrome were methods of food preparation (uncooked juice vs. stir fried or boiled dishes, matched OR 10.3 (95% confidence interval (CI) 1.3-84.4)); preparer of the S. androgynus-containing food (vendor only vs. patient only or patient plus vendor, matched OR 2.8 (95% CI 1.1-7.1)); total S. androgynus consumption quantity (> 4,500 vs. 413-2,063 g, matched OR 10.0 (95% CI 1.9-53.0)); duration of consumption (> 45 vs. 6-24 days, matched OR 2.1 (95% CI 1.2-3.8)); and midterm interruption (< 2 vs. 2-5 days per week, matched OR 2.6 (95% CI 1.1-6.1)). Additionally, multiple conditional logistic regression analysis of cases and self-referred patron controls revealed that a larger total amount of S. androgynus consumption, preparation of S. androgynus food without cooking, and ingesting S. androgynus food prepared by a vendor were the significant risk factors associated with bronchiolitis obliterans syndrome.

Analysis of Variance↗

Prognostic factors in patients with bulky stage IB or IIA cervical carcinoma undergoing neoadjuvant chemotherapy and radical hysterectomy.

All patients with bulky (> or =4 cm) Stage Ib or IIa cervical carcinoma treated at Chang Gung Memorial Hospital between August 1988 and December 1991 using a strategy of neoadjuvant chemotherapy with cisplatin, vincristine, and bleomycin and radical hysterectomy were reviewed. Fifty-nine evaluable patients received 1 to 3 courses of chemotherapy, and 51 underwent subsequent hysterectomy. The remaining 8 patients, not completing planned surgery, were treated with definitive radiotherapy. The overall clinical response rate was 81.4% (48/59) with 18.6% complete response. Clinical response to chemotherapy was not different by stage, histologic type, tumor size, level of squamous cell carcinoma antigen, or DNA ploidy. However, tumors with DNA indices (DI) greater than 1.3 were associated with higher clinical response rates than tumors with DI < or = 1.3 (P = 0.043). Histologically proven pelvic node metastases was noted in 18.5% (10/54) who had laparotomy. Concomitant pregnancy and more than one node metastases had significant adverse influence on recurrence and death. The 5-year survival rate of those patients who received hysterectomy was 80.3%, while only 1 of the 8 patients without hysterectomy survived. Of the 7 patients received hysterectomy despite clinical poor response, only 2 had node metastases and 3 died, whereas all the 4 patients deterred hysterectomy for poor response died. This study demonstrates the value of DNA flow cytometry in predicting chemosensitivity. However, with a DI cutoff at 1.3, only 29.2% patients could be selected. Further studies are necessary to find additional indicators that predict histological response to select better candidates for this approach and to determine optimal adjunctive treatment in case that poor prognostic features are found.

Adult↗

Referred pain elicited by palpation and by needling of myofascial trigger points: a comparison.

OBJECTIVE: To investigate the occurrence of referred pain (ReP) elicited by palpation (Pal-ReP) or by needle injection (Inj-ReP) of myofascial trigger point (MTrP), and to assess the correlated factors, including the pain intensity of an active MTrP and the occurrence of local twitch response (LTR). DESIGN: Correlational study. PATIENTS: Ninety-five patients who were treated with MTrP injections. INTERVENTION: MTrP injections. MAIN OUTCOME MEASURE: Pain intensity of MTrP and occurrence of Pal-ReP, Inj-ReP, and LTR. RESULTS: Both Pal-ReP and Inj-ReP were elicited in 53.9% of MTrPs, Inj-ReP, but not Pal-ReP, was elicited in 33.7% of MTrPs. Both Pal-ReP and Inj-ReP were unobtainable in 12.3% of MTrPs. The occurrence of ReP was significantly correlated to the pain intensity of active MTrP and the occurrence of LTR. CONCLUSION: ReP could be elicited more frequently by needling than by palpation. The frequency of occurrence in ReP mainly depends on pain intensity of an active MTrP.

Adult↗

Genetic and antigenic diversity of Ehrlichia chaffeensis: comparative analysis of a novel human strain from Oklahoma and previously isolated strains.

A new Ehrlichia strain, designated as Ehrlichia chaffeensis, Sapulpa strain, was isolated from a patient from Oklahoma with severe ehrlichiosis. Isolation of the ehrlichial pathogen was achieved by inoculating patient blood onto HEL cells and DH82 cells. Antigenic properties of the new isolate were characterized with monoclonal antibodies, homologous patient serum, and polyclonal rabbit serum by Western immunoblotting. The results showed antigenic differences and protein size variation of Sapulpa strain compared with the other 2 strains of E. chaffeensis. Sequencing of the 16S rRNA gene showed 100% identity to that of E. chaffeensis, strain 91HE17. Polymerase chain reaction and sequencing of DNA homologous to the 120-kDa protein gene of E. chaffeensis, Arkansas strain, showed that this gene of Sapulpa strain was smaller than that of Arkansas strain and contained a repeat region with three tandem repeat units.

Animals↗

Western immunoblotting analysis of the antibody responses of patients with human monocytotropic ehrlichiosis to different strains of Ehrlichia chaffeensis and Ehrlichia canis.

In order to evaluate the relative sensitivity of the detection of antibodies against various antigenic proteins of Ehrlichia chaffeensis for the diagnosis of the emerging infectious disease human monocytotropic ehrlichiosis, Western immunoblotting was performed with 27 serum samples from convalescent patients with antibodies, as demonstrated by indirect immunofluorescence assay. Among 22 patients with antibodies reactive with the 120-kDa protein, 15 showed reactivity with the 29/28-kDa protein(s) and the proteins in the 44- to 88-kDa range. Two of the serum samples with this pattern reacted with the 29/28-kDa protein(s) of only the 91HE17 strain, and one sample reacted with only that of the Arkansas strain, indicating that the antibodies were stimulated by strain-specific epitopes. Overall, antibodies to the 29/28-kDa protein(s) were detected in only 16 patients' sera, suggesting that this protein is less sensitive than the 120-kDa protein. Two of 12 serum samples from healthy blood donors had antibodies reactive with the 120-kDa protein; one of these samples reacted also with the 29/28-kDa protein(s) of Ehrlichia canis, suggesting that unrecognized ehrlichial infection might have occurred, including human infection with E. canis. A high correlation between reactivity with the 120-kDa protein by Western immunoblotting and the recombinant 120-kDa protein by dot blot supports the potential usefulness of this recombinant antigen in diagnostic serology.

Adult↗

The role of DNA flow cytometry in borderline malignant ovarian tumors.

BACKGROUND: The role of flow cytometric DNA analysis in predicting prognosis of patients with borderline malignant ovarian tumors has been controversial. METHODS: Fifty cases of patients with borderline malignant ovarian tumors were analyzed by histology and by flow cytometry on paraffin embedded tissue. Multiple tissue blocks and serial sections were analyzed for each tumor. The results of DNA analysis were correlated to clinicopathologic data. RESULTS: DNA aneuploidy was demonstrable in 4 cases (8%) when the most atypical section was analyzed. The overall rate of aneuploidy was 14% if additional blocks and serial sections were studied. Two patients died from tumor. One of the two patients had an initial diagnosis of Stage IIc mucinous borderline tumor with DNA indices (DI) of 1.12, 1.42, and 2.04. She had a recurrence in the contralateral ovary 1 year later (DI = 1.83), and a second frankly malignant recurrence diffusely in peritoneum (DI = 1.89). The other patient had an initial diagnosis of Stage IIIc mucinous borderline ovarian tumor with pseudomyxoma peritonei. DNA diploidy was obtained in all of the samples from the primary tumor. An aneuploid peak (DI = 1.28) was demonstrated in only one serial section of the peritoneal implants. Of the other 5 patients who had aneuploid histograms but were disease-free, the DNA indices were 1.35, 1.14/1.18, 1.15, 1.20, and 1.31 and were demonstrable only in either 1 or 2 of the blocks or unproven on serial sections. All patients with diploid-peridiploid tumors were alive and disease free. CONCLUSIONS: Reproducible DNA aneuploidy of high DI may be predicting a poor outcome, whereas the significance of inconsistently reproducible aneuploidy of low DI remains to be determined. Further studies of prospective DNA analysis with adequate sampling are necessary to define the role of flow cytometry in patients with borderline malignant ovarian tumors.

Adolescent↗

Ligand interactions with E-selectin. Identification of a new binding site for recognition of N-acyl aromatic glucosamine substituents of sialyl Lewis X.

Several N-acylglucosamine derivatives of sialyl Lewis X (1-3) were prepared using a combined chemical enzymatic approach and evaluated as an inhibitor of E-selectin-mediated cellular adhesion. Compounds with aromatic functionality, 1 and 2, were found to be 3-10 times more potent than the N-acetyl derivative (14) in an ELISA E-selectin cell adhesion assay. Conformational analysis with NMR indicated that the sialyl Lewis x domain of 1 retained the conformation of the N-acetyl derivative (14) despite the presence of the N-naphthamido group. The dramatic order of magnitude increase in potency of these monovalent structures can be utilized to design more potent selectin-based cell adhesion inhibitors.

Binding Sites↗

The impact of endoscopic variceal ligation on the pressure of the portal venous system.

BACKGROUND/AIMS: Endoscopic variceal ligation is a viable substitute for injection sclerotherapy. It is still not known how endoscopic variceal ligation may influence the portal venous system. To clarify this issue we investigated the impact of endoscopic variceal ligation on the pressure of the portal venous system. METHODS: Twenty-nine patients with a history of esophageal variceal bleeding but without ascites were enrolled. All had cirrhosis; 63% of them were post-hepatitic. Ligation was performed at intervals of 2-3 weeks until all the varices were obliterated. Portal venograms were performed before institution of ligation and after variceal obliteration to assess venographic findings and pressure changes. The pressures of the main portal vein, splenic vein and superior mesenteric vein were recorded. RESULTS: Twenty-five patients completed the study. A mean of 4.4 sessions (range: 2-7) of ligation over a period of 2 months was needed. Seventeen (68%) patients experienced elevated pressure and eight (32%) patients reduced pressure after ligation. Mean (median) pressure changes were as follows: portal venous pressure, 26.5 +/- 4.7 (25.0) mmHg vs. 28.2 +/- 7.2 (28.0) mmHg (p > 0.05); splenic venous pressure, 28.2 +/- 4.9 (26.0) mmHg vs. 29.0 +/- 6.8 (29.0) mmHg (p > 0.05); superior mesenteric venous pressure, 28.4 +/- 6.0 (27.0) mmHg vs. 29.5 +/- 7.0 (29.0) mmHg (p > 0.05). Five patients (20%) experienced rebleeding before variceal obliteration; all of them presented elevated portal pressures after variceal obliteration. Among the eight patients with decreased portal pressure, seven (87%) had other major collaterals apart from esophageal varices, compared to three out of the 17 (18%) patients with elevated portal pressure who had other major collaterals (p < 0.01). CONCLUSIONS: Among patients receiving endoscopic variceal ligation, 68% experienced elevated portal pressure, while 32% had decreased portal pressure. Elevation of portal pressure after variceal ligation may be an important factor in variceal rebleeding. The presence of other major collaterals apart from esophageal varices may be responsible for the decrease in portal pressure after obliteration of esophagel varices.

Adult↗

Effect of parathyroid hormone on antioxidant enzyme activity and lipid peroxidation of erythrocytes in five-sixths nephrectomized rats.

The purpose of the study was to investigate the effects of parathyroid hormone (PTH) infusion on antioxidant enzyme activity and lipid peroxidation of erythrocytes in five-sixths nephrectomized (Nx) rats. Five-sixths Nx rats had a higher osmotic fragility in red blood cells (RBC). Thyroparathyroidectomy (TPTX) effectively decreased the abnormality of osmotic fragility in RBC in Nx rats. PTH infusion in Nx-TPTX rats markedly increased the osmotic fragility in RBC. Total glutathione was measured by using the enzyme-recycling method. We found elevated glutathione levels in RBC of five-sixths Nx rats, but this elevation could be inhibited by TPTX and recovered by PTH infusion in Nx-TPTX rats. Five-sixths Nx rats had a lower glutathione peroxidase activity in RBC, but TPTX or PTH infusion was not found to alter the decrease of the glutathione peroxidase activity in RBC of five-sixths Nx rats. These rats had a higher activity in RBC superoxide dismutase as compared with sham-operated controls (p < 0.05), but the higher activity in RBC superoxide dismutase in Nx rats had been inhibited by TPTX. PTH infusion recovered the higher activity in RBC superoxide dismutase in five-sixths Nx-TPTX rats. Nx rats were not found to alter the activity of catalase in RBC. Neither could TPTX or PTH infusion in Nx rats influence the activity of catalase in RBC. A high lipid peroxidation in RBC was found in five-sixths Nx rats, namely, increased formation of malondialdehyde (MDA) in RBC had been induced to produce lipid peroxidation by H2O2, but neither TPTX nor PTH infusion could inhibit or enhance the increase of lipid peroxidation in RBC of Nx rats. These results indicate that PTH infusion did not increase the susceptibility to lipid peroxidation in RBC of five-sixths Nx rats. Thus, the increased osmotic fragility in RBC induced by PTH infusion may not result from the reduction in the RBC defense mechanism against free radical toxicity.

Animals↗

Gallbladder function and recurrent stones of the biliary tract in patients after endoscopic sphincterotomy.

BACKGROUND: Change in gallbladder function may occur in patients with an intact gallbladder after endoscopic sphincterotomy (EST). This study was designed to evaluate the factors influencing gallbladder filling after EST and the correlation between gallbladder function and stone recurrence. METHODS: Sixty Chinese patients with symptomatic choledocholithiasis and an intact gallbladder received EST to clear the bile ducts. They were further investigated with sphincter of Oddi manometry (SOM), quantitative cholescintigraphy (QC), and long-term clinical follow-up. RESULTS: Fifty-six of the 60 patients in the study group were confirmed to have a loss of sphincteric function by SOM. QC showed normal gallbladder filling in 35 of these patients and delayed or non-filling in 21 patients. A significantly higher incidence of normal gallbladder filling occurred in patients with juxtapapillary diverticulum than in those without (P < 0.02), but preexisting cholecystolithiasis had no effect on it. During the follow-up period (median, 32 months: range, 9-54 months) 10 of 56 patients developed recurrent choledocholithiasis. There was no correlation between the status of gallbladder filling, preexisting cholecystolithiasis, and recurrent stones, but 9 of the 10 patients with recurrent stones had a juxtapapillary diverticulum. Repeated endoscopic treatment was satisfactory in eight patients, and only two patients received cholecystectomy. CONCLUSIONS: EST does not alter gallbladder function in most patients. Juxtapapillary diverticulum may facilitate gallbladder filling after EST, but it is also a possible factor for recurrent choledocholithiasis.

Aged↗

Analysis and ultrastructural localization of Ehrlichia chaffeensis proteins with monoclonal antibodies.

Ehrlichia chaffeensis, an obligately intracellular bacterium with tropism for monocytes, is the etiologic agent of human monocytic ehrlichiosis. To determine the nature and ultrastructural location of E. chaffeensis antigens, monoclonal antibodies (MAbs) to E. chaffeensis were developed. The MAbs were used for immunofluorescence and Western immunoblotting analysis of the antigens of density gradient-purified ehrlichiae. Monoclonal antibody 6A1 recognized an epitope of a 30-kD protein. This antibody reacted with a strain-specific epitope of E. chaffeensis, Arkansas strain, and did not cross-react with any other ehrlichia tested. Monoclonal antibodies 3C7 and 7C1-B recognized Arkansas strain proteins of 30 and 29 kD and reacted with E. chaffeensis (strain 91HE17) proteins of 31 and 29 kD and an E. canis protein of 30 kD. Lack of reactivity of these two MAbs with E. sennetsu and E. risticii suggests that the epitope is group-specific. Monoclonal antibody 5D11 recognized a 58-kD protein of both strains of E. chaffeensis as well as E. canis, apparently a group-specific, conformation-independent epitope. Monoclonal antibody 7C1-C reacted with 58- and 88-kD proteins of both the Arkansas and 91HE17 strains. Trypsin treatment destroyed the reactivity of E. chaffeensis antigens with all the MAbs when tested by Western immunoblotting, indicating that these antigens are proteins with trypsin-sensitive epitopes. Immunoelectron microscopy of negatively stained intact E. chaffeensis organisms showed that the 30- and 29-kD proteins are present on the surface of the ehrlichial cell wall along with the previously localized 28-kD protein.

Animals↗

Study of isometric lifting strength in normal Chinese adults.

The purposes of this study were to describe norms of isometric lifting strength for healthy Chinese adults and to investigate the effects of age, gender, body weight, and body height on lifting strength. Three types of lifting (i.e., arm, back, and leg lifting) were measured in a sample of 350 Chinese adults (172 men and 178 women) aged between 20 and 81 years. A Force Evaluation and Testing System (FET 5000) was used for strength measurements with three standard lifting positions. The average of two trials for each lifting strength test was used as the subjects' test score. The results showed that the greatest strengths for both sexes exist aged between late 20's and early 30's, with a general decline following thereafter. The magnitude of strength decline with age was most prominent in leg lifting strength among all lifting patterns. Males were stronger than females in all lifting patterns among the different age groups. All of the lifting strengths studied correlated positively with gender, body weight, and body height, and negatively with age in the analyses of simple correlation coefficients. In addition, stepwise multiple regression analyses showed that sex, age and body weight were most predictive of all types of lifting strengths. Body height was an effective predictor of back lifting strength. These findings and the establishment of data base can provide therapists with an objective evaluation regarding lifting strength of individuals for clinical use.

Adult↗

Decreased tubular reabsorption of zinc in rats with chronic uremia.

Effect of chronic uremia on tubular reabsorption of zinc was studied in rats with different zinc nutritional status. Using inulin clearance to represent glomerular filtration rate and plasma ultrafiltrate to imitate glomerular filtrate in vivo, the glomerular filtered load of zinc was estimated in each rat. The amount of tubular reabsorption of zinc equals the amount of zinc filtered minus the amount of zinc excreted into the urine. Proportion of filtered zinc excreted was estimated to be 2.8-8.7% in control rats and 17.3-29.8% in uremic rats induced by five-sixths nephrectomy. Similarly, proportion of filtered zinc reabsorption decreased significantly from 91.3-97.3% in control rats to 70.1-82.7% in uremic rats. Zinc deficiency increased fractional reabsorption of zinc in uremic rats but not in control rats. Fractional excretion of zinc correlated with both urine flow rate and urinary excretion of protein. The results suggest that uremia toxins may influence tubular reabsorption of zinc even in the presence of renal adaptation to zinc deficiency.

Animals↗

Ultrastructural variation of cultured Ehrlichia chaffeensis.

The ultrastructure of Ehrlichia chaffeensis (Arkansas strain) was studied in non-irradiated and irradiated monolayers of mouse embryo, Vero, BGM and L929 cells, and in non-irradiated DH82 cells. Within the intracellular parasitophorous vacuoles (morulae), two types of ehrlichial cells were found regularly--those with uniformly dispersed nucleoid filaments and ribosomes (dense-cored cells), which represent the normal life cycle of ehrlichiae. In addition, large reticulate cells were observed, forming long projections of the cell wall, protrusions of cytoplasmic membrane into the periplasmic space, or budding of protoplast fragments (minute forms) into the periplasmic space. Ehrlichiae with abnormalities of protoplast fission were found, apparently leading to formation of giant, multilobular or elongated rod-like ehrlichiae. Morulae were usually surrounded by cisterns of granular endoplasmic reticulum and mitochondria and often contained vesicles, long tubules 25nm in diameter, probably originating from the ehrlichial cell wall, and fibrillar ehrlichial antigen apparently shed from the surface of the cell wall. Some cells contained, in addition to normal morulae, a whole morula that had become dense and contained degenerating ehrlichiae. These results indicate that as well as normal growth and reproduction, ehrlichiae exhibit pathological events: they can be remarkably damaged inside the host cell vacuoles, presumably phagolysosomes, or enter a process morphologically similar to bacterial L-transformation.

Animals↗

Cultivation of Ehrlichia chaffeensis in mouse embryo, Vero, BGM, and L929 cells and study of Ehrlichia-induced cytopathic effect and plaque formation.

We successfully propagated Ehrlichia chaffeensis in mouse embryo, Vero, BGM, and L929 cells inoculated with host cell-free ehrlichiae, indicating that E. chaffeensis is capable of entry, survival, and growth in a relatively wide range of cell types derived from different species. We demonstrated rapid adaptation of E. chaffeensis in these cell lines, so that typical morulae could be detected as early as 5 days after inoculation. E. chaffeensis-induced cytopathic effect with different morphological characteristics in mouse embryo, Vero, and L929 cells. The earliest cytopathic effect appeared in untreated and irradiated mouse embryo cells at 4 days postinoculation. As the infected foci gradually expanded, the center of the foci showed necrotic cells with pyknotic nuclei and degraded morulae. E. chaffeensis caused cell lysis in untreated and irradiated L929 cells, with formation of distinct, round macroscopic plaques at 18 days postinoculation. In untreated and irradiated Vero cells, E. chaffeensis produced infected foci composed of loosely interwoven necrotic cells, spaces of detached cells, cells filled with morulae, and uninfected cells, resulting in characteristic reticular foci. Irradiated cells generally contained many large morulae and presented larger cytopathic foci. DH82 and BGM cells did not develop obvious cytopathic foci under the conditions employed. The findings reported herein offer the opportunity to study the pathogenic mechanism of cell injury by E. chaffeensis, the basis for quantification of infectious E. chaffeensis, improved approaches for recovery of ehrlichiae from human patients and tick hosts, and additional methods for cultivation of E. chaffeensis for molecular analysis.

Animals↗

Isolation and characterization of a new strain of Ehrlichia chaffeensis from a patient with nearly fatal monocytic ehrlichiosis.

Ehrlichia chaffeensis is the causative agent of human monocytic ehrlichiosis, a disease that ranges in severity from asymptomatic infection to death. Only one isolate of E. chaffeensis has been made, the Arkansas strain, upon which all characterizations of the agent of human monocytic ehrlichiosis have been based. We report the isolation and characterization of a new strain of E. chaffeensis, the 91HE17 strain, which was cultivated from a patient with a nearly fatal illness. The new isolate grows best in culture with careful control of pH. The two isolates are nearly identical as determined by light and electron microscopy and have significant antigenic identity in fluorescent-antibody and immunoblot assays using polyclonal antisera and the E. chaffeensis-specific monoclonal antibody 1A9. Isolate 91HE17 had 99.9% nucleotide sequence identity with the Arkansas strain in the 16S rRNA gene. Parts of the Escherichia coli GroE operon homologs had identical restriction enzyme digestion patterns, and a 425-bp region of the GroEL gene had at least 99.8% sequence identity between the E. chaffeensis Arkansas and 91HE17 strains. Isolate 91HE17 lacked an epitope identified in E. chaffeensis Arkansas by the monoclonal antibody 6A1. This new E. chaffeensis isolate is very similar to the Arkansas strain and provides the opportunity to substantiate the existence of diversity among ehrlichiae which infect humans. Specific factors which differ among strains may then be compared to assess their potential contributions toward cellular pathogenicity and ultimately toward the development of disease in humans.

Aged↗

Ultrasonic detection of persistent small unilateral hematocolpos in two girls.

Two girls with unilateral hematocolpos are reported. In both cases, a small amount of blood which had accumulated in the partially obstructed hemivagina was detected by real-time high resolution ultrasonography, and was confirmed by magnetic resonance imaging. Both patients were asymptomatic, and were regularly followed up at an outpatient clinic. To date, the hematocolpos persists but continues to be small.

Adolescent↗