Biomedical subjects

H J Lin

Publications and source records attributed to H J Lin.

At least 91 records · Page 5Linked to original sources

PubMed1996

Occipital encephalocele and MURCS association: case report and review of central nervous system anomalies in MURCS patients.

The combination of MURCS association (Müllerian duct and renal agenesis, upper limb and rib anomalies) and occipital encephalocele occurred in a stillborn girl of 41 weeks gestation. The malformations are compatible with a defect in the organization of the paraxial mesoderm that gives rise to occipital, cervical, and thoracic somites and adjoining intermediate mesoderm. These structures contribute to the occipital bone, cervical spine, upper limbs, and urogenital system. Brain imaging may be useful in assessing MURCS patients, if cranial malformations prove to be clinically important in these individuals.

Abnormalities, Multiple↗

PubMed1996

Application of transcranial Doppler sonography in surgical aspects of hypertensive putaminal haemorrhage.

From May 1992 to February 1993, 22 cases of hypertensive putaminal haemorrhage (HPH) treated at our hospital were serially measured with transcranial Doppler (TCD) sonography. Among them, 13 patients underwent surgical intervention (3 stereotaxic surgery and 10 craniotomies), and 9 were conservatively treated. Most of the patients of the two operative groups had larger haematomas and developed clinical and/or neurological deterioration, which was the indication for subsequent surgery. Therefore the groups represent different clinical and physiological entities. On admission, the peak MCA velocities (Vs) in the surgical group (stereotaxic and craniotomy) were significantly lower than those in the conservative group (mean +/- S.E.M.: 38.33 +/- 4.26 and 42.00 +/- 2.62 cm/sec vs. 57.22 +/- 3.23 cm/sec; p < 0.005, respectively). The surgical group also had significantly lower diastolic (Vd) and mean (Vm) velocities than those of the conservative group (p < 0.001). Rather, the admission pulsatility indices (PI = (Vs-Vd)/Vm) in the surgical group were significantly higher than those of the conservative group (mean +/- S.E.M.: 1.42 +/- 0.04 and 1.31 +/- 0.09 vs. 0.95 +/- 0.01; p < 0.005, respectively). Time course velocity curves reached a peak around the 3rd hospital day in all the 3 groups. The Glasgow coma scale (GCS) scores positively correlated with the mean MCA velocities (n = 22; r = 0.63, p < 0.005; y = 2.04 x + 8.74), but negatively with PI values on admission (n = 22; r = -0.53, p < 0.05; y = 1.68-0.053 x). On the 7th hospital day, 2 patients with peak MCA velocities below 50 cm/sec had an unfavourable outcome. All the 3 patients in the stereotaxic group had higher peripheral resistance, as compared with those in conservative craniotomy groups (mean +/- S.E.M.: 1.28 +/- 0.13 vs. 0.99 +/- 0.07 and 0.87 +/- 0.06; p < 0.05, respectively). Our study supports TCD as a safe and valid monitoring method in patients with HPH. "Compromised cerebral haemodynamic status" (Vs < 50 cm/sec, Vd < 15 cm/sec, Vm < 25 cm/sec, PI > 1.15) may offer an aid in the decision for surgical intervention in HPH. Postoperatively, patients who made a favourable recovery had a significant increment in the MCA velocities in contrast to those severely disabled, whose MCA velocities remained low.

Adult↗

PubMed1996

Natural history of bleeding peptic ulcers with a tightly adherent blood clot: a prospective observation.

BACKGROUND: The natural history of a bleeding peptic ulcer with a tightly adherent blood clot remains uncertain. Controversy exists concerning removal of such blood clots at the bleeding ulcer base. This article presents the natural history of a bleeding peptic ulcer with a tightly adherent clot and defines the characteristics of those requiring aggressive management. METHODS: Clinical parameters were analyzed to determine the independent predictors of rebleeding in these patients. One hundred one patients with bleeding peptic ulcers and tightly adherent blood clots were enrolled during a period of 12 months. RESULTS: Twenty-five patients (25%) rebled within 1 month. With a multivariate analysis, we found comorbid illness (odds ratio, 3.41), shock (odds ratio, 3.65), and initial hemoglobin at or below 10 gm/dL (odds ratio, 2.99) to be independent predictors of rebleeding. CONCLUSIONS: Most patients with a tightly adherent clot in an ulcer have an uneventful course. However, endoscopic therapy may prove to be beneficial in the subset of patients with independent predictors of rebleeding.

Blood Coagulation↗

PubMed1996

Lack of association between the polyadenylation polymorphism in the NAT1 (acetyltransferase 1) gene and colorectal adenomas.

Smoking and a high intake of red meat are risk factors for colorectal tumors. These effects could be due to aromatic amine carcinogens. Individual susceptibility to aromatic amines has been related to acetylation phenotype, which plays a role in the bioactivation of arylamines. Polymorphisms in both N-acetyltransferase genes, NAT1 and NAT2, have been associated with an increased risk of colorectal tumors. We studied the NAT1*10 fast acetylator allele (1088 T-->A mutation) and distal adenomas in a sigmoidoscopy-based case-control study (441 cases, 484 controls). We found neither an increased adenoma prevalence in subjects homozygous or heterozygous for the NAT1*10 fast acetylator allele (odds ratio 1.04; 95% confidence interval 0.79-1.36), nor a gene-gene interaction between NA1 and NAT2 (P(interaction) = 0.59). Further NAT1 alleles must be considered for more conclusive results regarding the relevance of NAT1 activity to colorectal tumorigenesis.

Adenoma↗

PubMed1996

Early or delayed endoscopy for patients with peptic ulcer bleeding. A prospective randomized study.

The benefit of early endoscopy in the management of peptic ulcer bleeding remains controversial. In this study we looked at the role of early endoscopy in bleeding peptic ulcer patients with clear, "coffee grounds," or bloody nasogastric aspirate. A consecutive series of 325 patients with peptic ulcer bleeding were included (218 patients with clear aspirate, 77 patients with coffee-grounds aspirate, and 30 patients with bloody aspirate). They were randomized to receive early endoscopy (within 12 h of arrival at the emergency room) or delayed endoscopy (12 h after arrival at the emergency room). Early endoscopy did not benefit patients with clear or coffee-grounds aspirate. However, combined with endoscopic therapy, it did significantly benefit patients with bloody aspirate in reducing the need for blood transfusion (mean, 450 ml vs. 666 ml; p < 0.001) and hospital stay (mean, 4 vs. 14.5 days, p < 0.001). Early endoscopy and endoscopic therapy are not needed in bleeding peptic ulcer patients with clear or coffee-grounds nasogastric aspirate. However, early endoscopy and endoscopic therapy benefit patients with bloody nasogastric aspirate.

Aged↗

PubMed1996

Gastric secretion in Chinese patients with cirrhosis.

The role of gastric secretion has been controversial in patients with cirrhosis. Except for studies of gastric secretion in cirrhotic patients who underwent a shunt operation, there is no report correlating gastric secretion with portal pressure in patients with cirrhosis. In this study, we evaluated gastric secretion in cirrhotic patients and correlated it with hemodynamic parameters. Within 12 months, 20 normal volunteers and 16 cirrhotic patients were enrolled. Gastric secretion was assessed in all patients, but portal pressure hemodynamic studies were performed only in cirrhotic patients. We found that the median basal acid output, maximal acid output, and basal pepsin output in the controls (1.41 mmol/h, 9.2 mmol/h, and 0.02 mg/h, respectively) and in the cirrhotic patients (0.6 mmol/h, 7.84 mmol/h, and 1.5 mg/h, respectively) were not statistically different. However, maximal pepsin output was lower in the cirrhotic patients (1.5 mg/h) than in the normal subjects (5.14 mg/h) (p < 0.05). Gastric secretion correlated poorly with hepatic venous pressure gradient (HVPG) and the presence of congestive gastropathy in cirrhotic patients. The severity of congestive gastropathy correlated poorly with HVPG. Helicobacter pylori has difficulty replicating in the stomach when HVPG is > 14 mm Hg. We conclude that patients with cirrhosis have a lower maximal pepsin output than that of the healthy subjects. Gastric secretion correlates poorly with HVPG and the presence of congestive gastropathy in patients with cirrhosis.

Aged↗

PubMed1996

Evaluation of a quality assurance program for quantitation of human immunodeficiency virus type 1 RNA in plasma by the AIDS Clinical Trials Group virology laboratories.

A number of quantitative assays have been developed by using amplification techniques to measure human immunodeficiency virus type 1 RNA in the plasma of infected individuals. The Virology Committee of the AIDS Clinical Trials Group in the Division of AIDS, National Institute of Allergy and Infectious Diseases, has established a quality assurance program (QAP) for quantitative assays of HIV-1 RNA levels in plasma. The primary objective of the QAP was to ascertain that a laboratory could maintain the precision required to have a 90% power to detect a fivefold difference in RNA copy number between two samples in the same batch. To achieve this goal, the QAP required an intra-assay standard deviation of no greater than 0.15 log10 RNA copies per ml. Panels for proficiency testing consisted of coded replicate samples and a common set of standards. To date, 41 laboratories have participated in the program and have used both commercial and in-house assays. We demonstrated that 65% of the laboratories were capable of attaining the necessary level of intra-assay precision. The fitted regressions indicated that the differences among laboratories that used the same kit were generally greater than the differences among population-average regressions for the kits themselves. The use of an external QAP and a common set of standards reduced differences both among laboratories that used the same kit and among laboratories that used different kits. Thus, use of a common set of standards across clinical trial protocols would allow for cross-protocol comparisons.

Clinical Protocols↗

PubMed1996

Application of a commercial kit for detection of PCR products to quantification of human immunodeficiency virus type 1 RNA and proviral DNA.

Quantitative tests for human immunodeficiency virus type 1 (HIV-1) RNA in plasma and proviral DNA in peripheral blood mononuclear cells (PBMC) provide valuable information on the status of HIV-1 infection. This paper describes tests that were carried out with commercially available materials and an enzyme-linked immunosorbent assay reader for detecting spectrophotometric changes. Samples consisted of 100 microliters of plasma or 200,000 PBMC. The procedure involved sample preparation, PCR-based amplification with the primer pair SK39 (biotinylated at the 5' end) and SK38, hybridization of the cDNA PCR product to an RNA probe, capture of the RNA-DNA hybrid on a solid phase by means of strepavidin, binding to an alkaline phosphatase-conjugated antibody directed against RNA-DNA hybrids, and incubation with p-nitrophenylphosphate. Spectrophotometric changes were recorded at four intervals over a period of 20 h. The inclusion of HIV-1 RNA or proviral DNA standards in each run was an integral part of the procedure. The dynamic ranges afforded by these assays--500 to 1 million RNA copies per ml and 10 to 5,000 proviral DNA copies per 10(6) PBMC--were applicable to most plasma specimens and to all PBMC specimens from HIV-1-infected patients. Correlations of log-transformed HIV-1 RNA and proviral DNA concentrations with those found by reference methods were, respectively, 0.88 and 0.80. The between-run coefficients of variation for the detection method were < or = 25% (range, 9.1 to 24.7) and < or = 15% (range, 10.9 to 15.1), respectively, for HIV-1 RNA and proviral DNA. The reproducibility of the overall procedure for HIV-1 RNA in plasma (including sample preparation, amplification, and detection) was given by a duplicate standard deviation of log10 copies per ml of 0.11. Thus, the method was sufficiently precise to allow the detection of fourfold changes in plasma HIV-1 RNA concentrations, with a power of 0.95.

DNA, Viral↗

PubMed1996

Stroke severity in atrial fibrillation. The Framingham Study.

BACKGROUND AND PURPOSE: Stroke occurring with atrial fibrillation (AF) is more likely to be fatal or more severe than non-AF stroke based on clinical series, but data from prospective epidemiological studies are sparse and inconsistent. METHODS: Over 40-year follow-up of the original 5070 Framingham cohort, 501 initial ischemic strokes, including 103 with AF, were analyzed. Stroke severity was rated as none, mild, moderate, severe, or fatal. Since 1981, functional status indicated by the Barthel index has been evaluated acutely and at 3, 6, and 12 months. Severity and functional status of AF strokes were compared with non-AF strokes using chi 2 test and Student's t test. Thirty-day mortality was assessed by logistic regression analyses. RESULTS: AF was associated with increased stroke severity (P = .048). Thirty-day mortality was greater in AF strokes than in non-AF strokes (25% versus 14%). The multivariate-adjusted odds ratio for 30-day mortality for AF subjects was 1.84 (95% confidence interval, 1.04 to 3.27). Since 1981, follow-up was available for 150 initial ischemic strokes, including 30 with AF. Compared with the non-AF group, the AF group had poorer survival and more recurrences during 1 year of follow-up. The AF subjects had lower mean Barthel index scores acutely (29.6 versus 58.6, P < .001) and at 3 months (P = .005), 6 months (P = .003), and 12 months (P = .130) after stroke among survivors. CONCLUSIONS: Ischemic stroke associated with AF was nearly twice as likely to be fatal as non-AF stroke. Recurrence was more frequent, and functional deficits were more likely to be severe among survivors. Since stroke is usually the initial manifestation of embolism in AF, prevention is critical to reducing disability and mortality.

Adult↗

PubMed1996

Characteristics of patients with benign gastric outlet obstruction requiring surgery after endoscopic balloon dilation.

OBJECTIVES: The aim of this study is to identify factors that will predict which patients with benign gastric outlet obstruction will not respond to endoscopic balloon dilation, in a long-term observation. METHODS: Over a 51-month period, 42 patients with benign gastric outlet obstruction received endoscopic balloon dilation. The "through-the-scope" technique with the aid of a guide wire was used for dilation. Fifteen factors were analyzed prospectively in 40 patients. Multivariate analysis was used to find the independent factors of the failure of treatment. RESULTS: The median follow-up period was 23 months (range 1-51 months). Twenty-eight (67%) patients achieved sustained improvement, and 14 (33%) patients underwent surgery. The overall symptom-free rates in 12, 24, 36, and 48 months were 85.3%, 78%, 68.8%, and 68.8%, respectively. The independent prognostic factor for failure of treatment was the need for more than two courses of endoscopic balloon dilation to relieve symptoms (odds ratio, 6.857; 95% confidence interval, 1,031-45,606). CONCLUSIONS: Endoscopic balloon dilation for the treatment of benign gastric outlet obstructions is an effective alternative to surgery. Patient who needs more than two courses of endoscopic balloon dilation to relieve symptoms should receive surgery.

Adult↗

PubMed1996

Intravenous omeprazole prevents rebleeding in peptic ulcer patients with a non-bleeding visible vessel: a preliminary report of a randomized controlled study.

BACKGROUND: In patients with peptic ulcer bleeding, acid can enhance platelet disaggregation and cause lysis of the clot. Omeprazole, a potent acid suppressor, may be helpful in reducing their rebleeding rate. METHODS: Between March and October 1994, 40 patients with a non-bleeding, visible vessel (NBVV) at ulcer bases were enrolled for study. They were randomized into four groups. Group 1 (n = 10) patients received cimetidine 300mg intravenously (i.v.) q6h; Group II (n = 10) patients received heater probe thermocoagulation therapy and cimetidine 300mg i.v. q6h; Group III (n = 10) patients received omeprazole 40mg intravenous bolus initially followed by 40mg i.v. qd and Group IV (n = 10) patients received omeprazole 40mg intravenous bolus initially followed by 40mg i.v. q12h. Endoscopic examination was done for follow-up, daily, for 1-3 days. RESULTS: Preliminary results showed that the age, initial hemoglobin, ulcer size as well as NBVV size in Groups I-IV were not significantly different (p < 0.05). The rebleeding rates were 40% in Group I, 20% in Group II, 20% in Group III and 0% in Group IV, (p < 0.05 when Group IV is compared with Group I). CONCLUSIONS: Intravenous omeprazole 40mg given q12h can reduce the rebleeding rate of patients with a NBVV.

Adult↗

PubMed1996

Immunohistochemical pattern of P53 protein in human astrocytic tumors.

P53 immunohistochemistry in astrocytic tumors has usually been evaluated by the percentage of positive cells. However, in this study we analyzed the P53 immunopositive cells by their patterns of distribution. Formalin-fixed and paraffin-embedded sections from 38 patients with astrocytic tumors were examined. The distribution pattern of P53 immunostaining cells was divided into 3 types: negative, locally scattered, and diffuse clustering. There were 2 positive stains in 5 astrocytomas (40%), 12 positive in 24 anaplastic astrocytomas (50%), and 7 positive in 9 glioblastoma multiformes (78%). In astrocytomas, the positive cells were locally scattered. In anaplastic astrocytoma and GBM, the positive cells appeared locally scattered or as diffuse clustering. For the variant immunoreactive expression, the mean ages for patients with negative, locally scattered and diffusely clustered P53 immunostaining were as follows: 51.4, 52.6, and 28.4 years (P < 0.01), respectively. In anaplastic astrocytoma and GBM, the diffusely clustered pattern was more common in younger patients, whereas elderly patients in same groups tended to have few or no P53 immunopositive cells. Thus, our results implicate that clonal expansion of P53 immunopositive cells is associated with brain tumor progression.

Adolescent↗

PubMed1996

Computed tomography, endoscopic ultrasonography and intraoperative assessment in TN staging of gastric carcinoma.

In a prospective study from November 1989 to December 1993, the accuracy of computed tomography (CT), endoscopic ultrasonography (EUS) and intraoperative surgical assessment were compared for the evaluation of the depth of invasion (T category) and involvement of lymph nodes (N category) in patients with gastric carcinoma. Sixty-nine consecutive patients who received preoperative CT and EUS underwent subsequent surgery. CT and EUS results were compared with histopathologic staging of tumor invasion depth and regional lymph node metastasis (pT and pN categories). T categories were staged correctly in 42% of the cases by CT, 71% by EUS and 55% by intraoperative surgical assessment. CT correctly staged 49% of N1 and N2 lymph nodes compared with 65% for EUS and 45% for intraoperative surgical assessment. CT was more accurate for advanced cancer but had a tendency to understage the T and N categories. EUS was more accurate for serosal cancer and displayed a tendency to overstage T categories and understage N categories. Intraoperative surgical assessment overstaged early T stages, understaged the T4 stage and had a tendency to overstage N categories. CT and intraoperative surgical assessment of T and N categories were of limited value in the staging of gastric carcinoma compared to EUS. EUS is a valuable form of assessment to evaluate gastric cancer staging before surgery.

Adenocarcinoma↗

PubMed1996

Omeprazole plus amoxicillin versus triple therapy eradicates Helicobacter pylori in the Chinese with peptic ulcer disease.

BACKGROUND: Omeprazole/amoxicillin regimen has proved elsewhere to be effective in the eradication of Helicobacter pylori (H. pylori). However, in the Chinese, its role in H. pylori is still unclear. METHODS: Between November 1993 and June 1994, 112 patients with active, H. pylori positive peptic ulcer were enrolled in this study. Five groups were arranged randomly to have 20 mg omeprazole q.d. for 28 days plus 750 mg amoxicillin b.i.d. for the first 10 days (omep-20-amox group, N = 22), 20 mg omeprazole b.i.d. for 28 days plus 750 mg amoxicillin b.i.d. for the first 10 days (omep-40-amox group, N = 22), 300 mg bismuth subsalicylate q.i.d. for 28 day, and 750 mg amoxicillin b.i.d., 500mg metronidazole t.i.d. for the first 7 days (triple therapy group, N = 25), 20 mg omeprazole q.d. for 28 days (omep-20 group, N = 22), or 150 mg ranitidine b.i.d. or 400 mg cimetidine b.i.d. for 28 days (H2-antagonist group, N = 21). RESULTS: The eradication rate of H. pylori eight weeks after the entry of study was 38.1% in the omep-20-amox group, 66.7% in the omep-40-amox group, 77.3% in the triple therapy group, 4.7% in the omep-20 group and 0% in the H2 antagonist group (p < 0.05 between the triple therapy and the omep-20-amox, the omep-20, and the H2 antagonist groups). Eleven patients in the triple therapy group suffered from adverse effects (45.8%) (p < 0.05 as compared with other groups). The ulcer healing rates four weeks after the entry of study for the omep-20-amox, the omep-40-amox, the triple therapy, and the omep-20 groups were 80.9%, 80.9%, 68.2%, and 85.7% respectively (p > 0.05). For the H2 antagonist group, the ulcer healing rate eight weeks after the entry of study was 70%. CONCLUSIONS: Both medium-dose omeprazole/amoxicillin and triple therapy can achieve good eradication rates. However, medium-dose omeprazole/amoxicillin had a much lower side effect. Therefore, we recommend medium-dose omeprazole/amoxicillin for the eradication of H. pylori.

Adult↗

PubMed1995

Microdontia with severe microcephaly and short stature in two brothers: osteodysplastic primordial dwarfism with dental findings.

Two brothers from a black family had microcephaly, short stature, and generalized microdontia. Endocrine and chromosome studies were normal, and mild skeletal manifestations were present. The patients may represent a distinct dental-skeletal dysplasia, possibly osteodysplastic primordial dwarfism type II. Attention to dental manifestations in similar cases may be useful for classification.

Adolescent↗

PubMed1995

Glutathione transferase (GSTM1) null genotype, smoking, and prevalence of colorectal adenomas.

Colorectal cancer is caused by environmental exposures and genetic predisposition. However, little is known of hereditary factors that influence development of common, non-Mendelian forms of this cancer. Interactions among carcinogen exposure, hereditary variants of enzymes involved in carcinogen metabolism, and other host factors may play a role. Genetic polymorphisms of carcinogen metabolism, such as the glutathione transferase M1 (GSTM1) null genotype, are thus possibly related to cancer risk. The GSTM1 enzyme detoxifies mutagens formed from polycyclic aromatic hydrocarbons which are found in tobacco smoke. We analyzed GSTM1 genotypes and smoking among 488 controls and 446 individuals with a first time diagnosis of colorectal adenomas which are precursors to cancer. Subjects were from two Kaiser Permanente sigmoidoscopy clinics in southern California. We observed no overall effect of the GSTM1 null genotype on the risk for colorectal adenomas (odds ratio, 0.85; 95% confidence interval = 0.65-1.10). The odds ratio for smokers with the null genotype was 2.07 (95% confidence interval = 1.14-3.77) when compared to "never smokers" without the null genotype. Using this same reference group, the odds ratio for smokers without the null genotype was 1.73 (95% confidence interval = 1.03-2.90). These two odds ratios were not significantly different (P = 0.30).

Adenoma↗

PubMed1995

Molecular evolution of the hepatitis B virus genome.

The hepatitis B virus (HBV) has a circular DNA genome of about 3,200 base pairs. Economical use of the genome with overlapping reading frames may have led to severe constraints on nucleotide substitutions along the genome and to highly variable rates of substitution among nucleotide sites. Nucleotide sequences from 13 complete HBV genomes were compared to examine such variability of substitution rates among sites and to examine the phylogenetic relationships among the HBV variants. The maximum likelihood method was employed to fit models of DNA sequence evolution that can account for the complexity of the pattern of nucleotide substitution. Comparison of the models suggests that the rates of substitution are different in different genes and codon positions; for example, the third codon position changes at a rate over ten times higher than the second position. Furthermore, substantial variation of substitution rates was detected even after the effects of genes and codon positions were corrected; that is, rates are different at different sites of the same gene or at the same codon position. Such rates after the correction were also found to be positively correlated at adjacent sites, which indicated the existence of conserved and variable domains in the proteins encoded by the viral genome. A multiparameter model validates the earlier finding that the variation in nucleotide conservation is not random around the HBV genome. The test for the existence of a molecular clock suggests that substitution rates are more or less constant among lineages. The phylogenetic relationships among the viral variants were examined. Although the data do not seem to contain sufficient information to resolve the details of the phylogeny, it appears quite certain that the serotypes of the viral variants do not reflect their genetic relatedness.

Codon↗

PubMed1995

Single-strand conformation polymorphism study of human immunodeficiency virus type 1 RNA and DNA in plasma, peripheral blood mononuclear cells, and their virologic cultures.

Single-strand conformation polymorphism (SSCP) analysis was applied to human immunodeficiency virus type 1 (HIV-1) nucleic acids in plasma and peripheral blood mononuclear cells (PBMC) from 16 patients and to 15 PBMC cocultures and 6 plasma cultures prepared from the specimens. Two hypervariable regions were analyzed: in the gag gene and part of the V3 loop. Random paired matching of SSCP patterns between HIV-1 RNA and provirus DNA was tested, from plasma and PBMC from the same blood specimen, supernatant and PBMC from the same PBMC coculture, supernatant and PBMC from the same plasma culture, provirus DNA in cocultured PBMC and the PBMC inoculum, and HIV-1 RNA in a plasma culture supernatant and in the plasma inoculum. Paired matching was nonrandom for both regions in the first three situations and for gag in the fourth, with P < or = .01; matching was random for gag in the last situation. The HIV-1 env target region produced in culture diverged from that in the inoculum in 18 of 21 instances.

Base Sequence↗